Abstract: Rapid and reliable exclusion of acute myocardial infarction during emergency department triage is an important clinical need. The purpose of this study was to evaluate the potential role of copeptin, a marker of acute endogenous stress, together with high sensitive troponin-I for a rapid and early rule-out of acute myocardial infarction.
Abstract: Abstract Laboratory diagnostics (i.e., the total testing process) develops conventionally through a virtual loop, originally referred to as "the brain to brain cycle" by George Lundberg. Throughout this complex cycle, there is an inherent possibility that a mistake might occur. According to reliable data, preanalytical errors still account for nearly 60%-70% of all problems occurring in laboratory diagnostics, most of them attributable to mishandling procedures during collection, handling, preparing or storing the specimens. Although most of these would be "intercepted" before inappropriate reactions are taken, in nearly one fifth of the cases they can produce inappropriate investigations and unjustifiable increase in costs, while generating inappropriate clinical decisions and causing some unfortunate circumstances. Several steps have already been undertaken to increase awareness and establish a governance of this frequently overlooked aspect of the total testing process. Standardization and monitoring preanalytical variables is of foremost importance and is associated with the most efficient and well-organized laboratories, resulting in reduced operational costs and increased revenues. As such, this article is aimed at providing readers with significant updates on the total quality management of the preanalytical phase to endeavour further improvement for patient safety throughout this phase of the total testing process.
Abstract: 1,25-Dihydroxyvitamin D displays immunoregulatory and anti-inflammatory properties, and the cells involved in innate and adaptive immune response express the vitamin D receptor and can both produce and respond to this hormone. This article aims at describing the complex immune regulatory role of vitamin D and depicting whether a correlation exists between atrophic type A gastritis and hypovitaminosis. We studied 62 autoimmune gastritis (AIG) patients and compared them to 54 lymphocytic gastritis patients, 21 Helicobacter pylori gastritis patients and 212 healthy subjects. We also statistically analyzed vitamin D concentration in 36,384 outpatients referred to our clinical laboratories. 25-Hydroxyvitamin D levels, the measurable metabolite used to determine vitamin D status in plasma, were measured by a chemiluminescent method. Average level of 25-OHD in AIG subjects was 9.8 ± 5.6 ng/mL (95% confidence interval (CI) 8.4-11.2), 11.1 ± 8.4 (CI 7.5-14.7) in H. pylori gastritis patients, 22.2 ± 13.5 (CI 18.6-25.8) in nonspecific lymphocytic gastritis patients, 21.3 ± 12.2 (CI 19.7-22.9) in healthy subjects, and 21.8 ± 13.1 (CI 21.7-21.9) in the 36,384 outpatients. Vitamin D levels in AIG patients were significantly lower than in patients with nonspecific gastritis or in the general population, supporting the hypothesis that hypovitaminosis D might be a risk factor for the development of autoimmune diseases. The low vitamin D concentration in H. pylori gastritis patients might act as predisposing factor for a more severe Th1-type aggression to the stomach epithelium.
Abstract: We examined association of inducible myocardial perfusion defects with cardiorenal biomarkers, and of diminished left ventricular ejection fraction (LVEF) with kidney injury marker plasma neutrophil gelatinase-associated lipocalin (NGAL). Patients undergoing nuclear myocardial perfusion stress imaging were divided into 2 groups. Biomarkers were analyzed pre- and poststress testing. Compared to the patients in the low ischemia group (n = 16), the patients in the high ischemia group (n = 18) demonstrated a significantly greater rise in cardiac biomarkers plasma BNP, NT-proBNP and cTnI. Subjects were also categorized based on pre- or poststress test detectable plasma NGAL. With stress, the group with no detectable NGAL had a segmental defect score 4.2 compared to 8.2 (P = .06) in the detectable NGAL group, and 0.9 vs. 3.8 (P = .03) at rest. BNP rose with stress to a greater degree in patients with detectable NGAL (10.2 vs. 3.5 pg/mL, P = .03). LVEF at rest and with stress was significantly lower in the detectable NGAL group; 55.8 versus 65.0 (P = .03) and 55.1 vs. 63.8 (P = .04), respectively. Myocardial perfusion defects associate with biomarkers of cardiac stress, and detectable plasma NGAL with significantly lower LVEF, suggesting a specific heart-kidney link.
Abstract: BackgROUND/AIMS: recently, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) proposed a new equation for estimating glomerular filtration rate (eGFR), which could potentially replace the Modified Diet for Renal Disease Study (MDRD) equation in routine clinical use. Our aim was to evaluate the correlation between them and to compare the prevalence of each CKD stage using these two equations.
Abstract: Part of this document has been endorsed as a Position Statement on Point of Care testing (in-hospital setting) of the Italian Society of Laboratory Medicine (Società Italiana di Medicina di Laboratorio, SIMeL) and also refers to official documents and International standards to for generalities (ISO 15189/2003) and specific items (ISO 22870/2006). As such, this article is based on to professional standards, guidelines and peer reviews documents, and it is aimed to improve the pre-analytical, analytical and post-analytical phase of point of care testing (POCT), by providing insights into definitions, key aspects in developing a diagnostic system for POCT, benefits and risks of POCT and leading sources of errors.
Abstract: Lipoproteins reporting is inhomogeneous between laboratories and could be a challenge for clinical pathologists both because the clinical question is not unique and because there are many different lipids and lipoproteins that could be measured with variable performances. Moreover, comparison systems cannot be based on the reference intervals theory, but proper decision levels have to be chosen for the evaluation and interpretation of the results. In the cardiovascular disease (CVD) risk evaluation, the risk assessment is a global evaluation and the same lipid concentration could have more or less importance, associated with the other risk factors. The National Cholesterol Education Program-Adult Treatment Panel III suggests reporting different decision levels as desirable, border line-high abnormal and high abnormal. However, it would be better to integrate information derived by lipid concentration with the other risk factor, as age, diabetes, high blood pressure, smoke, reporting the global risk. In the drug monitoring defined decision levels are recommended by authoritative guidelines, with more than one decision limit per test, according to the patient risk. Some problems are given by the continuous update of these limits towards lower levels, more efficient in the CVD prevention, but inducing more aggressive drug therapies. Finally, new lipids or lipoproteins are proposed to substitute total and fractioned cholesterol and triglycerides. Lipoproteins ratios reporting, as total Cholesterol/HDL Cholesterol, seems to be more predictive in the populations with elevated CVD risk and having good performances also in the secondary prevention. The number of atherogenic particles is stronger correlated with CVD than the concentration level of cholesterol contained in the same particles. So, measurement of Apolipoproteins B and A-I seems to be more accurate than the measure of HDL and LDL-Cholesterol concentrations. ApoB/ApoA-I ratio has a higher positive predictive value that every other lipid, lipoproteins or combined panel. Lp(a) has a proved but lower utility, while other tests have less evidence, as l’Apo A-II, Apo B48, Apo C, Apo D e Apo E o Small- LDL Cholesterol. Conclusions. Lipoproteins reporting, particularly in the risk assessment, is a decision making action that could decide for a drug therapy. This decision could be very efficient in patients with elevated CVD risk or inappropriate in subjects with low risk, also if with high lipoproteins levels.
Abstract: Laboratory turnaround times (TATs) for urgent (Stat) tests are indicators of efficiency, and many clinicians consider prolonged TAT one of the most important causes for delay in transferring patients from emergency departments. Here, we present a review of the main proposed solutions, dependent on size, organization models and mission of the hospital. Although there is no clear evidence that laboratory TAT could be directly related to patient care, we need to continuously evaluate each laboratories performance by comparing them to patient outcomes.
Abstract: Background. Previous papers showed and increased percentage of haemolysed samples by using intravenous catheters, compared to venipuncture, and vice versa. Nevertheless, intravenous catheters are preferred by emergency departments and intensive care units, since they reduce the number of punctures needed, with an increment of sample rejection for haemolysis. There are no studies on the catheter materials and the possible differences in the haemolysis percentages. Aim of this study is to verify the correlation between the percentage of not suitable samples for haemolysis and different catheters materials, in an emergency hospital department. Methods. We compared the rejection percentages for haemolysis of samples come from the Emergency Department, during a period of 78 consecutive days. 91 specimens were obtained by BD Insyte™ Autoguard ™ (group A), 92 by intravenous catheter B Vasofix ® Safety (group B), 90 by Terumo Surflo-w (group C) and 90 by Neo Delta Ven T (group D). All catheters had a needle of 18 gauge. 100 consecutive samples drawn by a needle 21 gauge directly connected to the holder, coming from the Intensive Care Deparment, were used as control group. Results. Enrolled patients were 463 in all. In group A, 19/83 samples (22.9%) were hemolysed; in group B, 14/77 (18.2%); in group C 17/74 (23%); and in group D, 14/87 (16.1%). In the control group there was a 3% of rejected samples. Conclusions. All the catheters for venipuncture show higher percentages of haemolysis compared to direct venipuncture. Some differences are registered between different materials, without however statistical significance. These data confirm that intravenous catheters are not suitable for a correct venous blood sample collection.
Abstract: BACKGROUND: In vitro hemolysis, the prevailing cause of preanalytical error in routine laboratory diagnostics, might influence the reliability of several tests, affect the quality of the total testing process and jeopardize patient safety. Although laboratory instrumentation is now routinely equipped with systems capable of automatically testing and eventually correcting for hemolysis interference, to our knowledge there are no reports that have compared the efficiency of different analytical platforms for identifying and classifying specimens with hemolysis. METHODS: Serum from a healthy volunteer was spiked with varying amounts of hemolyzed blood from the same volunteer, providing a serum free hemoglobin concentration ranging from 0.0 g/L to 2.0 g/L as measured by the reference cyanmethemoglobin assay. The spiked serum samples were shipped to seven separate laboratories and the hemolysis index (HI) was tested in triplicate on the following analytical platforms: Roche Modular System P (n=4) and Integra 400 Plus (n=1), Siemens Dimension RxL (n=3), ADVIA 2400 (n=1) and ADVIA 1800 (n=1), Olympus AU 680 (n=1) and Coulter DXC 800 (n=1). RESULTS: Satisfactory agreement of HI results was observed among the various analytical platforms, despite a trend toward overestimation by the ADVIA 2400 and 1800. After normalizing results according to the instrument-specific alert value, discrepancies were considerably reduced. All instruments except for the Dimension RxL gave values normalized to the instrument-specific alert value, <1.0 for the sample with 0.048 g/L free hemoglobin, and >1.0 for the sample with 0.075 g/L free hemoglobin. The results of the four Modular System P tests were also highly reproducible among the different facilities. When evaluating instruments that provided quantitative HI results, the mean intra-assay coefficient of variation (CV) calculated for the triplicate determinations was always between 0.1% and 2.7%. CONCLUSIONS: The results of this multicenter evaluation confirm that efficiency of different analytical platforms to correctly identify and classify unsuitable samples is satisfactory. However, more effort should be placed on the standardization of reporting HI. All the instruments that we tested provide either quantitative or qualitative results that are essentially comparable, but which should always be compared with the instrument-specific alert values to harmonize their efficiency.
Abstract: The adoption of Evidence Based Laboratory Medicine (EBLM) has been hampered until today by the lack of effective tools. The SIMeL EBLM e-Thesaurus (on-line Repertoire of the diagnostic effectiveness of the laboratory, radiology and cardiology test) provides a useful support to clinical laboratory professionals and to clinicians for the interpretation of the diagnostic tests. The e-Thesaurus is an application developed using Microsoft Active Server Pages technology and carried out with Web Server Microsoft Internet Information Server and is available at the SIMeL website using a browser running JavaScript scripts (Internet Explorer is recommended). It contains a database (in Italian, English and Spanish) of the sensitivity and specificity (including the 95% confidence interval), the positive and negative likelihood ratios, the Diagnostic Odds Ratio and the Number Needed to Diagnose of more than 2000 diagnostic (most laboratory but also cardiology and radiology) tests. The e-Thesaurus improves the previous SIMeL paper and CD Thesaurus; its main features are a three languages search and a continuous and an easy updating capability.
Abstract: The self-monitoring of blood glucose (SMBG), traditionally performed by "point-of-care" (POC) devices called portable glucose monitors (PGM) is now considered an integral part of managed care of diabetic patients, especially type 1 diabetics and those on insulin therapy. In patients with type 2 diabetes, SMBG can help to achieve a better glycaemic control, although there is not sufficient evidence to attest that strict monitoring in these patients is associated with an improved outcome. The outcome of several clinical studies, especially in diabetics on insulin therapy, has shown that SMBG plays a key role in preventing complications in the short, medium and long term. According to the current recommendations, SMBG is aimed to achieve and maintain glycaemic control, prevent and identify hypoglycaemia, prevent severe hyperglycaemia, adjust lifestyle changes and establish the need to begin treatment with insulin in gestational diabetes mellitus. However, as clearly highlighted by the American Diabetes Association (ADA) and the National Academy of Clinical Biochemistry (NACB), patients and healthcare personnel should be trained on the appropriate use of the device, as well as on the correct interpretation of data. Moreover, definite analytical targets and appropriate acceptance criteria for performance should be fulfilled before a new device is introduced in the hospital environment, or recommended to the patients. Performance limitations such as hematocrit extremes and analytical interferences should be clearly acknowledged by the operators, before taking test results for granted. The current article aims to review the current indications for SMGB and highlight the most important criteria for the appropriate use of PGMs.
Abstract: Recommendations for detection and management
of critical values in clinical laboratories
Critical values (also known as panic or alarm values)
highlight a laboratory test result associated with a serious
risk for the patient’s health, requiring immediate
communication to the physician to establish appropriate
and punctual therapeutic interventions. Although critical
values are universally recognized as essential standards
for the good laboratory practice, their implementation
and management still represent matter of
debate worldwide. Since the implementation of standardized and universally accepted procedures appears
as yet an essential policy to provide rational and efficient
solutions to this issue, the present document is
aimed to provide consensus recommendations for
detection and management of critical values in clinical
laboratories.
The document is issued by the Italian Society of Clinical
Biochemistry and Clinical Molecular Biology
(SIBioC), the Italian Society of Laboratory Medicine
(SIMeL), with the Italian Committee for Standardization
of Laboratory and Haematological Methods
(CISMEL), through the Intersocietary Study Group
(GdS) on “Standardization of extra-analytical variability
of laboratory resultsâ€.
Key words: critical values, panic values, alert values, laboratory
testing.
Abstract: Background. Under the pressure of growing technologies
and the contraction of the staffs, most of the clinical
laboratories must reorganize their work and the
shift models. Aims of this survey is to compare the
workshift in the Veneto Region, regarding the emergency,
night and holiday work, to verify the homogeneity
of the used shifts and to derive helping models.
Methods. We pooled the biomedical scientists (BSs)
managers of all the 40 public clinical laboratories in
Veneto, about the number of the BSs employed (full
or part-time), managers, BSs involved in the workshift,
number of people in shift at the same time, schedule
and shift type (time, period, time off).
Results. Respondents rate was 95%; 11 laboratories have
a BSs staff under 10 units, 13 between 11 and 20, 6
between 31 and 40 and the last 2 over 40 units. There
are many differences among the adopted shift models:
BSs on call for labs with less personnel, shift or
double shift for the larger ones, but with wide differences
in time, period and time off.
Conclusions. The workshift model for BSs are related to
the number of BSs employed and consequently to the
workload of the laboratories. However there are wide
differences between each other, especially for the bigger
ones. Many laboratories with night workshift use
to add one day time off after the shift, but someone
keeps the morning/night schedule, coming for nursing
models: this shift avoids the 11 hours time off
between two shifts, as provided for by D. Lgs 66/
2003.
Abstract: The difference between an ‘Information’ and a ‘notice’ lies in the former’s ability to remove or significantly reduce someone’s uncertainty about something. In Laboratory Medicine, you have to know exactly how to ask a clinical question, i.e. what are you looking for, in order to get a plausible answer. A test result, the same test result, is going to get completely different information depending on the clinical context where you decided to order it, namely for screening or diagnosis rather than for monitoring or follow up. The first step in Evidence Based Laboratory Medicine is asking an answerable clinical question, e.g. using a popular tool as the Fagan’s nomogram you have to get some clinical (pre-test) information in order to evaluate the post-test probability. As a laboratory physician you must understand the clinical question; the other way round, clinicians must be aware of the more relevant pre-analytical, analytical and post-analytical issues. How the laboratory reports its results is paramount for clinicians to understand their real meaning. A typical Laboratory report is made of a list of figures sided by reference intervals, set to dimension the biological signal. Common practice and professional standards such as ISO 15189 and CPA UK both ...
Abstract: We evaluated the analytical performance of the new commercial HemosIL D-Dimer HS, a latex-enhanced turbidimetric immunoassay, from Instrumentation Laboratory for D-dimer measurement on the ACL TOP automated analyzer. The recommended cut-off for this immunoassay is 243 ng/ml. The within-run and between-run coefficients of variations of D-Dimer HS for low, intermediate and high D-dimer concentrations were: 3.3-6.6%, 2.3-2.6%, 2.4-3.2%, respectively. The assay was proven linear in a range of D-dimer concentrations comprised between 319 and 2274 ng/ml. Results of 171 citrated plasma samples were compared with those of the reference commercial immunoassay VIDAS D-Dimer. Although the nonparametric regression according to the method of Passing and Bablok and the relative Spearman's correlation coefficient were excellent (HemosIL D-Dimer HS = 1.30 x VIDAS - 384; r = 0.964, P < 0.001), some discrepancies could be observed in Bland-Altman plots analysis. On the basis of the present evaluation, we conclude that the analytical performance and the main technical features of new HemosIL D-Dimer HS assay make it a suitable method for the rapid quantification of D-dimer in clinical laboratories. Further studies are however needed to confirm the safety of the assay and to determine the most optimal cutoff level in patients with venous thromboembolism.
Abstract: CONTEXT: The reference limits for thyroid antibodies are generally made by measuring thyroid peroxidase and thyroglobulin antibody values in a group of healthy subjects (direct method), as proposed by the National Academy of Clinical Biochemistry. OBJECTIVE: To define the upper reference limits of thyroid peroxidase and thyroglobulin, by using an indirect method to analyze data from a large number of outpatients that were stored in the information system of a general hospital laboratory. DESIGN: Thyroid peroxidase and thyroglobulin values from 21 492 patients, who had undergone antithyroid antibody measurements, were retrieved from the laboratory information system; the upper reference limits (in the top 97.5 percentile) were calculated using the indirect Kairisto method, after exclusion of outliers. RESULTS: The mean upper reference limits for females and males were 15 kIU/L and 9 kIU/L for thyroid peroxidase, and 21 kIU/L and 19 kIU/L for thyroglobulin, respectively. The upper limits showed minimal or no differences in the different age classes in either females or males. CONCLUSIONS: Using a vast population of patients, we demonstrated that the upper limits for thyroid antibodies are much lower than the values obtained with classic, direct methods and that they do not vary in relation to age and sex.
Abstract: A large body of evidence attests that quality programs developed around the analytical phase of the total testing process would only produce limited improvements, since the large majority of errors encountered in clinical laboratories still prevails within extra-analytical areas of testing, especially in manually intensive preanalytical processes. Most preanalytical errors result from system flaws and insufficient audit of the operators involved in specimen collection and handling responsibilities, leading to an unacceptable number of unsuitable specimens due to misidentification, in vitro hemolysis, clotting, inappropriate volume, wrong container or contamination from infusive routes. Detection and management of unsuitable samples are necessary to overcome this variability. The present document, issued by the Italian Inter-society SIBioC-SIMeL-CISMEL (Society of Clinical Biochemistry and Clinical Molecular Biology-Italian Society of Laboratory Medicine-Italian Committee for Standardization of Hematological and Laboratory Methods) Study Group on Extra-analytical Variability, reviews the major causes of unsuitable specimens in clinical laboratories, providing consensus recommendations for detection and management.
Abstract: The variation between different PSA assays seems to influence the interpretation of individual PSA values and the clinical decisions about prostate cancer. One reason for this variability could be the different reactivity of antibodies for the various molecular forms of serum PSA; as a result, samples containing the same amount of tPSA but different proportions of fPSA can produce very different values. In this study, serum samples were collected prospectively from 152 consecutive patients referred to 2 institutions (Regional Hospital, Venice, 90 subjects; San Bortolo Hospital, Vicenza, 62 subjects) for PSA elevation and/or symptoms. Serum samples were assessed according to the manufacturers' instructions on the following 2 analyzers: the Immulite 2000 assay (Diagnostic Products Corporation, Los Angeles, USA), which measures tPSA and fPSA, and the ADVIA Centaur (Bayer Diagnostics, Tarrytown, USA), which assays tPSA and cPSA. cPSA values were transformed into fPSA by the equation fPSA=tPSA-cPSA. When taking Immulite tPSA and f/tPSA values as 100%, ADVIA Centaur values were 92.6% and 122%, respectively, which means that 20% of patients would be classified differently according to the traditional biopsy cutoff. In conclusion, there are considerable differences between the 2 methods, which could affect clinical decisions.
Abstract: OBJECTIVES: To determine pediatric reference values for thyrotropin using Advia Centaur analyzer. DESIGN AND METHODS: The study was conducted in a large regional hospital on TSH results obtained from 5741 females and 4332 males aged 0-17 years. After the exclusion of the results outside 4 standard deviations, we calculated the Health Related Limits (HRLs) following the indirect Kairisto's procedure and using the software GraphROC. RESULTS: The lower HRL of TSH concentration was 0.70 mU/L in the years 0-11 and 0.50 mU/L in the following years. The upper TSH HRL was 6.9 mU/L in males vs. 5.7 mU/L in females in the first year and 6.7 mU/L vs. 5.3 in the period 1-2 years. The upper HRLs in females and males were similar in the following years and the upper HRL in the 13-17 years class was 3.8 mU/L. CONCLUSIONS: The indirect methods appear reliable for calculating the pediatric HRLs for TSH.
Abstract: BACKGROUND: Critical values' reporting is an essential requisite for clinical laboratories. Local policies were investigated within an indicative cohort of Italian laboratories to monitor the situation and establish a performance benchmark. METHODS: A five-point questionnaire was administered to 150 laboratory specialists attending the SIMEL (Italian Society of Laboratory Medicine) National Meeting in June 2006. RESULTS: A total of 107 questionnaires (71.3%) were returned with a 100% individual question response rate. Only 55% of the participants acknowledge critical values reporting as an essential practice, 80% admit that a comprehensive list of critical values is unavailable in the laboratory and 4% do not promptly communicate critical values. The list of critical values is variable among laboratories, ranging from none to 20 analytes included. The requesting physician or his/her office staff receives the great majority (97%) of notifications by telephone for outpatients. Critical values for inpatients are notified directly by telephone (81%) and in a minority of cases by either fax or computer (19%). In the inpatient setting, the information is notified to physicians (77%), nurses (15%) or other healthcare staff in the clinic (8%). It was found that 49% of the participants adopt a standard (digital or written) policy for routine recording of notifications; in 32% of the cases the registration is left to individual attitudes, whereas in 20% of the cases the notification is not recorded. No laboratory has yet adopted a read-back verification of the complete test result by the person receiving the information. CONCLUSIONS: The importance of critical value reporting is still poorly recognized in Italy and uniform or internationally accredited practices for communication and recording are not currently implemented.
Abstract: BACKGROUND AND AIMS: Guidelines for the primary prevention of cardiovascular disease recommend the use of risk-assessment methods to identify high risk patients who can benefit from lifestyle changes and/or drug treatment. Although all these risk-prediction methods are based on the same principle, they produce different risk estimates. The aim of this study was to compare the most recent and widely used cardiovascular risk-prediction methods and the respective guidelines when applied to Italian cohorts. METHODS AND RESULTS: Seven different risk-assessment methods were applied to two groups of subjects, 536 healthy individuals and 426 diabetic patients. Sensitivity and specificity of Framingham-based risk-assessment methods were calculated using the Framingham full equation as the reference standard. The extent of concordance among the different risk-assessment methods was determined by kappa test. By using NCEP-ATPIII risk calculator, modified Sheffield tables, Joint European Societies charts, Joint British Societies charts, Italian CUORE Project charts, European SCORE charts and New Zealand National Heart Foundation charts in the group of 536 healthy subjects, lipid-lowering treatment would be recommended in 17.5%, 12.7%, 12.1%, 8.6%, 5.0%, 4.7%, and 1.1% subjects, respectively. By using the same risk-assessment methods in the group of 426 diabetic patients, treatment would be recommended for 100%, 82.9%, 66.9%, 77.7%, 43.0%, 74.9%, and 47.4% patients, respectively. The Joint British charts and the modified Sheffield tables showed the closest agreement with the reference standard. CONCLUSIONS: Our study confirms that the use of different risk-assessment methods in clinical practice can substantially change risk estimation and consequently statin prescription rate. The Framingham-based risk-assessment methods and particularly the NCEP-ATPIII guidelines select for lipid-lowering treatment a higher number of subjects than those identified according to European and Italian recommendations.
Abstract: BACKGROUND: Owing to remarkable advances in automation, laboratory technology and informatics, the pre-analytical phase has become the major source of variability in laboratory testing. The present survey investigated the development of several pre-analytical processes within a representative cohort of Italian clinical laboratories. METHODS: A seven-point questionnaire was designed to investigate the following issues: 1a) the mean outpatient waiting time before check-in and 1b) the mean time from check-in to sample collection; 2) the mean time from sample collection to analysis; 3) the type of specimen collected for clinical chemistry testing; 4) the degree of pre-analytical automation; 5a) the number of samples shipped to other laboratories and 5b) the availability of standardised protocols for transportation; 6) the conditions for specimen storage; and 7) the availability and type of guidelines for management of unsuitable specimens. The questionnaire was administered to 150 laboratory specialists attending the SIMEL (Italian Society of Laboratory Medicine) National Meeting in June 2006. RESULTS: 107 questionnaires (71.3%) were returned. Data analysis revealed a high degree of variability among laboratories for the time required for check-in, outpatient sampling, sample transportation to the referral laboratory and analysis upon the arrival. Only 31% of laboratories have automated some pre-analytical steps. Of the 87% of laboratories that ship specimens to other facilities without sample preparation, 19% have no standardised protocol for transportation. For conventional clinical chemistry testing, 74% of the laboratories use serum evacuated tubes (59% with and 15% without serum separator), whereas the remaining 26% use lithium-heparin evacuated tubes (11% with and 15% without plasma separator). The storage period and conditions for rerun/retest vary widely. Only 63% of laboratories have a codified procedure for the management of unsuitable specimens, which are recognised by visual inspection (69%) or automatic detection (29%). Only 56% of the laboratories have standardised procedures for the management of unsuitable specimens, which vary widely on a local basis. CONCLUSIONS: The survey highlights broad heterogeneity in several pre-analytical processes among Italian laboratories. The lack of reliable guidelines encompassing evidence-based practice is a major problem for the standardisation of this crucial part of the testing process and represents a major challenge for laboratory medicine in the 2000s.
Abstract: It is known that the erythrocyte sedimentation rate is related to the erythrocyte concentration in blood. Recently, some authors have proposed a method for estimating the relation between the Westergren erythrocyte sedimentation rate and the erythrocyte sedimentation rate adjusted on an hematocrit of 0.35 L/L. In this study we firstly evaluated in 236 samples the relation between the erythrocyte sedimentation rate measured by the TEST 1 analyzer in samples corrected to 0.35 L/L of hematocrit and the erythrocyte sedimentation rate measured in undiluted samples, and the hematocrit and the hemoglobin concentration, obtaining a multiple correlation coefficient of 0.956; (p < 0.001). Comparison between the corrected for HCT erythrocyte sedimentation rate, measured vs estimated, showed a bias of 0.0 (0.95 CI: -0.98 to 0.98 mm/h) with an agreement limit +/- 14.5 mm/h. Then, the reference intervals for the estimated erythrocyte sedimentation rate at 0.35 L/L of hematocrit were calculated by means of an indirect method (Kairisto), using the one-year stored data (47810 results) in our laboratory database. Our data showed that the erythrocyte sedimentation rate corrected to 0.35 L/L of hematocrit could be estimated by a simple formula using the TEST 1 results; the reference ranges were higher than the reference ranges for uncorrected samples. New reference intervals were needed for an improved evaluation of the patients, and a table of reference intervals for age and sex is presented.
Abstract: Recent guidelines have defined that the decisional cut-off of cardiac troponin (cTn) would recognize "the normal" subjects, and in theory they do not have "measurable" values of cTn. The 99th percentile of this population is chosen as cut-off but using an assay with an analytical CV < 10% at this value. Objectives of this study were to set the decisional limits for cTroponin I (cTnI) measured by the ADVIA:Centaur, and to evaluate the analytical precision around these limits. 120 normal plasma samples were tested for cTnI levels. The 99th percentile defined the decisional level, according to the recent guidelines. The precision was estimated by 10 replicates for 21 samples. The 99th percentile was 0.17 microg/L, with an analytical CV <10%. Since this analytical method achieves the recommended analytical precision, the cTnI decision level for myocardial damage by the ADVIA:Centaur is 0.17 microg/L.
Abstract: The correct monitoring of heparin therapy and its reversal determines the successful conduct of cardiovascular surgery with extracorporeal circulation (ECC). The activated coagulation time (ACT) and the heparin management test (HMT) are the most frequently used tests in the operating room. Three compact monitors for ACT or HMT are here evaluated. Forty samples were obtained, at 10-min intervals, from eight patients during ECC. The ACT or HMT was immediately performed using: Hemochron juniors ACT, CoaguCeck Pro (ACT) and Rapid Point Coag (HMT). Data were compared between them and with the heparin levels, measured as anti-Xa. The simple least squares linear regression among, respectively, Hemochron Junior ACT, CoaguCeck Pro ACT, Rapid Point Coag HMT and anti-Xa activity were i=452.3, s=15.2, Sy/x=37.5, r=0.18; i=411.9, s=22.1, Sy/x=48.7, r=0.21 and i=479.4, s=9.0, Sy/x=9.3; r=0.41. CoaguCeck Pro ACT results were above the upper detection limit (500 s) in 37 of 40 determinations. The comparison between ACT Hemocron and HMT Rapid Point Coag shows i=35.7, s=0.9, Sy/x=35.4, r=0.68, with a bias of 29.0 s (CI: 17.9-40.1), 95% of agreement between -41.5 s (CI: -60.7 to -22.3) and 99.5 s (CI: 80.4-118.7). Taking a concentration of 2.0 U/ml of heparin to discriminate between high- and low-risk conditions, receiver-operator characteristic (ROC) curve was used to rank the performance of the methods. Areas under the ROC curve+/-SE for Hemochron Junior ACT and Rapid Point Coag HMT were 0.629+/-0.097 and 0.543+/-0.096. The results obtained by HMT appear similar to those obtained by the ACT for monitoring high-dose heparin therapy in patients undergoing ECC. HMT appeared to perform better than ACT in measuring the heparin effect, while the ROC analysis gives a little more accuracy for ACT. Neither of the two methods is able to achieve enough evidence of diagnostic accuracy. Since these tests are widely used, and there are no laboratory alternatives, a real comparison with the outcome of the patients should be helpful for an evidence-based evaluation of these point-of-care tests.
Abstract: The TEST 1 is a fully automated analyzer for measurement of the erythrocyte sedimentation rate. This system employs a particular capillary where blood is moved by a special hydrodynamic system. This original method is not able to measure stabilized samples for quality control, probably because stabilized erythrocytes offer a higher resistance to movement into the capillary, giving a distorted sedimentation curve. We evaluated whether the stability of collected EDTA samples, as declared by the producer company, was sufficient to use samples measured the day before as internal quality control samples. We also evaluated whether different tubes could modify the test results between stored and fresh samples. The difference between ESRs measured in fresh and stored samples are non-relevant after 24h and 48h, using both the tubes considered. The agreement between fresh and stored samples was better than that obtained by comparison with the Westergren method and can be used for the internal quality control procedure.
Abstract: We describe procedures, results and prospects of a pilot program in External Quality Assessment (EQA) of the stat test intralaboratory turnaround times. Our goals are to promote quality by systematic monitoring and comparison of performances by laboratories, continuous investigation into the state of the art of the processes from receipt of sample to transmission of results and creation of a data base for standardization of measures and definition of consensus values for turnaround time. Of 30 laboratories invited to participate, 25 took part, agreeing to record times of arrival and transmission for all determinations of three analytes (blood hemoglobin, serum/plasma potassium and plasma prothrombin time) for seven consecutive days and to continue for one or more further periods of seven days as necessary if there were less than 300 determinations for each analyte. Within a preset time limit, data were sent by e-mail on an Excel file and we sent back two reports per analyte, showing: i) the graph for time vs. percentage of tests completed and several measures of turnaround time; ii) results of all laboratories in graph form, allowing each laboratory to identify only its own data. The high proportion of participating laboratories among those invited (83%) encourages us to implement the EQA program systematically, on a half-yearly basis, extending it to all laboratories wishing to participate in Italy or elsewhere in Europe.
Abstract: OBJECTIVES: We sought to obtain a noninvasive estimation of mean pulmonary wedge pressure (MPWP) in patients with chronic atrial fibrillation (AF). BACKGROUND: It has previously been demonstrated that MPWP can be reliably estimated from Doppler indexes of mitral and pulmonary venous flow (PVF) in patients with sinus rhythm. Doppler estimation of MPWP has not been validated in patients with AF. METHODS: MPWP was correlated with variables of mitral and pulmonary venous flow velocity as assessed by Doppler transthoracic echocardiography in 35 consecutive patients. The derived algorithm was prospectively tested in 23 additional patients. RESULTS: In all patients the mitral flow pattern showed only a diastolic forward component. A significant but relatively weak correlation (r = -0.50) was observed between MPWP and mitral deceleration time. In 12 (34%) of 35 patients, the pulmonary vein flow tracing demonstrated only a diastolic forward component; a diastolic and late systolic forward flow was noted in the remaining 23 patients (66%). A strong negative correlation was observed between MPWP and the normalized duration of the diastolic flow (r = -0.80) and its initial deceleration slope time (r = -0.91). Deceleration time > 220 ms predicted MPWP < or = 12 mm Hg with 100% sensitivity and 100% specificity. When estimating MPWP by using the equation MPWP = -94.261 PVF deceleration time -9.831 Interval QRS to onset of diastolic PVF -16.337 Duration of PVF + 44.261, the measured and predicted MPWP closely agreed with a mean difference of -0.85 mm Hg. The 95% confidence limits were 4.8 and -6.1 mm Hg. CONCLUSIONS: In patients with chronic AF, MPWP can be estimated from transthoracic Doppler study of PVF velocity signals.
Abstract: Patients with end-stage renal disease (ESRD) who undergo hemodialysis manifest pronounced oxidative stress (OS), for the antioxidant system is inadequate to correct the imbalance between generation and scavenging of reactive oxygen species (ROS). To clarify the role of two different membranes on the OS, we measured plasma lipid peroxidation (LPO) and erythrocyte concentration of several antioxidant enzymes on 20 controls and 6 patients on bicarbonate dialysis (BHD). At 7 days intervals, 2 BHD sessions were done on the same 6 hemodialysis patients: the two BHD sessions were similar, except for the membrane used (cuprophan, first study; regenerated cellulose = Bioflux, second study, 7 days later). Before, during, and after each session (0', 30', 60', 120', end, 30' after BHD end), several blood samples were drawn. Lipid peroxidation and erythrocyte glutathione (GSH), superoxide dismutase (SOD), and catalase were spectrophotometrically determined (Bioxytech, France), but for erythrocyte glutathione peroxidase (Gpx) and G-6-PD, Gunzler's and Beutler's methods were used, respectively. Both membranes induce a significant decrease in LPO (p < 0.01) and an increase in erythrocyte SOD (p < 0.05). Bioflux shows some peculiar effects: a significant increase in erythrocyte GSH (p < 0.05) and erythrocyte catalase (p < 0.01) with a gradual increase of erythrocyte SOD and catalase/SOD ratio. Cuprophan, on the contrary, causes a sudden increase in erythrocyte SOD, while erythrocyte catalase decreases. These data support the view that Bioflux induces an OS lower than cuprophan because with the former, increased H2O2 production leads (thanks to catalase and GPx action) to water generation. With cuprophan, instead the reduced SOD/catalase ratio causes a greater H2O2 generation and a lower conversion to water.
Abstract: Paraoxonase is a high-density lipoprotein (HDL)-associated enzyme capable of hydrolysing lipid peroxides. We measured the activity of serum paraoxonase together with serum concentrations of a variety of lipid constituents--total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), cholesterol, triglycerides, apolipoproteins A-I and B--in 60 hemodialyzed (HD) patients. We found that the paraoxonase activity was significantly reduced in HD patients compared with 64 healthy controls (mean median and interquartile values: 93, 63, 87 IU/l in HD patients and 151, 120 and 135 IU/l in controls). In patients, the trimodal frequency of distribution of paraoxonase activity showed a shift toward lower levels. The effect of NaCl on enzyme activation was more pronounced in the patient group, as compared with controls, suggesting a higher frequency of the B allozyme (more responsive to NaCl) in this population. We suggest that altered HDL subfraction, present in HD patients, may be the main cause of the widespread depression of paraoxonase. Furthermore, the higher frequency of allozyme B among HD patients might increase the risk of coronary artery disease. In conclusion, paraoxonase activity may be an adjunctive index of altered lipoprotein metabolism with important repercussions on atherosclerosis.
Abstract: The defenses against the production of free radicals and reactive oxygen species (ROS) are to be found in plasma (ascorbate, urate, alpha tocopherol) and in erythrocytes (superoxide dismutase or SOD; catalase or CAT; glutathione peroxidase or GPx). In chronic renal failure, an increased lipid peroxidation and a reduced antioxidant activity seem to be present, but previous reports are conflicting. To clarify the peroxidative status and the defense mechanisms taking place in patients on dialysis, in 30 patients on dialysis (15 men, 15 women) and in 20 control subjects (10 men, 10 women), the following parameters were measured: plasma 4-hydroxinonenal (4-HNE) and erythrocyte reduced glutathione (GSH), SOD, GPx, and glucose-6-phosphate dehydrogenase (G-6-PD). Patients on dialysis, in comparison with control subjects, had 1) increased levels of 4-HNE (p < 0.001); 2) a significant increase in erythrocyte-GSH (p < 0.05); and 3) significant decreases in erythrocyte-SOD (p < 0.001), erythrocyte-G-6-PD (p < 0.005), and the erythrocyte-SOD/GPx ratio (p < 0.001). The dialysis procedure induced a certain reduction in plasma 4-HNE, an increase in erythrocyte-SOD activity, and an important consumption of erythrocyte-GSH, while the erythrocyte-SOD/GPx ratio changed. The current study supports the view that 1) erythrocytes act as small detoxifying packets; 2) in chronic renal failure, the antioxidant system is largely inadequate; and 3) in patients on dialysis, the antioxidant mechanism of erythrocytes in scavenging ROS is effectively exerted during dialysis but remains largely inadequate, as signs of lipid peroxidation persist with time.
Abstract: We have determined CT levels in whole serum (iCT) and by an extraction method (exCT) in 25 infants affected by congenital hypothyroidism (CH)--11 athyreotic and 14 dysgenetic--at age 25 days, before the institution of therapy, and at age 2 years. In hypothyroid patients at age 25 days the iCT and exCT levels were similar to those found in controls of the same age. At age 2 years the iCT and exCT levels decreased in both groups of patients. However, whereas the levels of iCT in hypothyroids were similar to those found in controls of the same age, the levels of exCT were significantly lower in hypothyroids than in controls; moreover they were significantly lower in athyreotic than in dysgenetic patients. At this age, after calcium infusion, exCT levels significantly increased in dysgenetic but not in athyreotic patients. We hypothesize that CT deficiency in CH is due to increased degradation of human CT by the substitutive therapy, which, stimulating proteolytic enzymes, destroys the biologic activity of CT. An extraction procedure improves the sensitivity and specificity of the CT assay and it must be used when CT deficiency is suspected. In addition we suggest that the measurement of exCT levels after Ca infusion might be useful to distinguish dysgenetic from athyreotic patients.
Abstract: Blood levels of glucose, insulin (IRI), Calcium (Ca), phosphorus (P), alkaline phosphatase (AP), osteocalcin (OC), parathyroid hormone (PTH), calcitonin (CT), 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and urinary excretion of Ca (Ca/Cr), P (TmP/GFR), hydroxyproline (OH-P/Cr) and cyclic AMP (cAMP/GFR) were determined in 16 obese children, aged 8 to 11 years, on a diet rich in calories and carbohydrates and in 15 controls of the same age. Blood glucose, IRI, Ca, P, PTH and CT were also determined in both groups of subjects, during an oral glucose tolerance test (OGTT). In basal conditions glucose, IRI, AP, OC, PTH, CT and 1,25(OH)2D3 levels were significantly higher, and 25OHD3 levels lower, in obese children than in controls. Urinary Ca/Cr, TmP/GFR were lower in obese than in non obese children, while OH-P/Cr and cAMP/GFR were higher. Bone mineral content (BMC), measured by photon absorptiometry, and BMC/bone width ratio were lower in obese than in non obese children. During OGTT serum Ca and P decreased and serum PTH and CT increased less in obese than in non obese children. In obese children receiving a diet with high carbohydrate content, an alteration of mineral metabolism occurred, characterized by secondary increase of PTH and 1,25(OH)2D3. Ca decreased and PTH and CT increased less markedly during OGTT.
