Volume 44, Issue 12

Atherosclerosis is widely regarded as a chronic inflammatory disease that develops as a consequence of entrapment of low-density lipoprotein (LDL) in the arterial intima. Native LDL lacks inflammatory properties, so the lipoprotein must undergo biochemical alterations to become atherogenic. Among several other candidates, two different concepts of lipoprotein modification are propagated, the widespread oxidation hypothesis and the less common E-LDL hypothesis, which proposes that modification of LDL occurs through the action of ubiquitous hydrolytic enzymes (enzymatically modified LDL or E-LDL) rather than oxidation. By clearly distinguishing between the initiation and progression of atherosclerotic lesion development, this article reviews comparative studies of both types of lipoprotein modification and submits a viewpoint for discussion proposing that these lipoprotein modifications do not really compete, but rather complement one another. According to this concept, E-LDL might be more important for the initiation of atherosclerosis, while oxidative modification of LDL might be more helpful for diagnosis and prognosis of the disease. Clin Chem Lab Med 2006;44:1389–94.

Blood doping consists of any illicit means used to increase and optimize oxygen delivery to the muscles and includes blood transfusions, administration of erythropoiesis-stimulating substances, blood substitutes, natural or artificial altitude facilities, and innovative gene therapies. The use of blood transfusion, an extremely straightforward, practical and effective means of increasing an athlete's red blood-cell supply in advance of competition, became rather popular in the 1970s, but it has suddenly declined following the widespread use of recombinant human erythropoietin among elite endurance athletes. Most recently, following implementation of reliable tests to screen for erythropoiesis-stimulating substances, blood transfusions have made a strong resurgence, as attested by several positive doping tests. Doping by blood transfusion can be classified as homologous, where the blood is infused into someone other than the donor, and autologous, where the blood donor and transfusion recipient are the same. The former case produces more clinically relevant side effects, but is easily detectable using current antidoping protocols based on erythrocyte phenotyping by flow cytometry and, eventually, erythrocyte genotyping by DNA testing. Since the donor and recipient blood are identical in autologous blood doping, this is less risky, though much more challenging to detect. Indirect strategies, relying on significant deviations from individual hematological profiles following autologous blood donation and reinfusion, are currently being investigated. For the time being, the storage of athletes' blood samples to allow testing and sanctioning of guilty athletes once a definitive test has been introduced may represent a reliable deterrent policy. Clin Chem Lab Med 2006;44:1395–402.

Background : Positive molecular detection of tyrosinase transcripts ( TYR mRNA) in RNA extracts of peripheral blood (PB) samples from patients with malignant melanoma provides evidence of disease dissemination. Methods : Total RNA extracted from PB was quantified and subjected to RT-PCR under ultra-sensitive and reduced-sensitivity PCR conditions using SSRT-II. Positive TYR mRNA detection in 78 melanoma patients and 40 healthy volunteers was correlated with clinical stage, Breslow's evaluation of tumor thickness, Clark's assessment of tumor invasion, the location of the primary tumor site, and tumor histology. The assay sensitivity was evaluated by spiking PB with the melanoma cell line SK-MEL-28. Results : Using ultra-sensitive PCR conditions, eight out of 40 RNA (20%) samples from healthy volunteers and 50 out of 78 RNA (64.1%) samples from melanoma patients tested positive. Using reduced-sensitivity PCR conditions, we found only two positives in 40 RNA samples from healthy subjects and 20 positives in 78 RNA samples (25.6%) from melanoma patients. Only positive PCR samples for the reduced-sensitivity PCR assay correlated significantly with stage IV (metastatic) disease (p=0.0395). There was no significant correlation between positive TYR mRNA samples for either PCR condition (ultra-sensitive and reduced-sensitivity) with Breslow's classification of tumor thickness, Clark's assessment of tumor invasion, location of the primary tumor site, and type of tumor histology. Conclusions : We conclude that reduced-sensitivity rather than ultra-sensitive PCR conditions correlate with clinical stage in melanoma patients. Clin Chem Lab Med 2006;44:1403–9.

Background : Recently cell-free plasma DNA has been described as a marker of apoptosis during hemodialysis (HD), but little is known about how different dialysis membranes may contribute to this process or whether pre-HD levels are restored afterwards. Here we evaluate the influence of the dialysis membrane on cell-free plasma DNA levels and investigate the clearance of plasma circulating DNA after HD. Methods : Cell-free plasma DNA was measured using a real-time quantitative PCR for the β-globin gene. Reference values for plasma DNA were established in a group of 100 healthy voluntary blood donors. Pre- and post-HD levels were also measured in 30 patients with end-stage renal disease on regular HD (52 sessions; 104 samples). The sessions lasted for 2.5–5h. Different dialysis membranes were compared: high-flux (n=37) vs. low-flux (n=15) and polysulfone (n=42) vs. modified cellulose (n=10). To determine the time at which pre-HD levels are restored, DNA was quantified in serial plasma samples obtained from 10 of these 30 patients, just before and immediately after HD, as well as at 30, 60 and 120min after HD. Results : Reference plasma DNA values for healthy blood donors ranged from 112 to 2452gEq/mL (median 740gEq/mL). Cell-free plasma DNA levels significantly increased during HD (Wilcoxon test for paired samples, p<0.0001), with increases of more than four-fold observed in 75% of the patients after HD. There was no significant linear association between the length of the HD session (between 2.5 and 5h) and the increase in cell-free plasma DNA concentration (Pearson correlation). No significant differences were observed between different types of membranes (Mann-Whitney U-test). Plasma DNA returned to pre-HD levels by 30min after HD, regardless of the starting concentration. Conclusions : Plasma DNA levels significantly increase after a conventional 2.5–5-h HD session. Therefore, HD patients require special consideration for correct interpretation of plasma DNA concentrations. This parameter can be considered a reliable diagnostic tool for certain pathologies when measured at least 30min after a HD session without further complications. The different dialysis membranes used in this study had no influence on cell-free plasma DNA concentrations, so the level of circulating DNA is not an appropriate marker of dialysis membrane biocompatibility. Clin Chem Lab Med 2006;44:1410–5.

Background : Hei Yi (which means black worship and black dressing) Zhuang is a specific subgroup of the Zhuang nationality in China. Little is known about the relationship between genetic factors and lipid profiles in this population. Therefore, the present study was undertaken to compare the effects of lipoprotein lipase gene polymorphism at the Pvu II locus on lipid levels in the Guangxi Hei Yi Zhuang and Han populations. Methods : A total of 325 Hei Yi Zhuang subjects aged from 20 to 80years were surveyed using stratified randomized cluster sampling. Serum levels of lipids and apolipoproteins were measured. Gene polymorphism was determined using polymerase chain reaction and restriction fragment length polymorphism. The results were compared with those for 331 matched Han subjects living in the same district. Results : Serum levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol and apolipoprotein B were significantly lower in Hei Yi Zhuang than in Han subjects (p<0.05–0.01), whereas the levels of high-density lipoprotein cholesterol and the ratio of apolipoprotein A1 to apolipoprotein B were significantly higher in Hei Yi Zhuang than in Han subjects (both p<0.01). The allelic frequencies for P+ and P– were 52.92% and 47.08% in Hei Yi Zhuang, and 58.46% and 41.54% in Han subjects (p<0.05), respectively. The frequencies of P+P+, P+P– and P–P– genotypes were 23.08%, 59.69% and 17.23% in Hei Yi Zhuang, and 29.31%, 58.31% and 12.38% in Han subjects (p>0.05), respectively. There were no significant differences or no significant correlation between serum lipid parameters and genotypes in Hei Yi Zhuang or Han subjects, or for the combined population of Hei Yi Zhuang and Han (all p>0.05). Conclusions : The allelic frequencies of the lipoprotein lipase gene at the Pvu II locus in Hei Yi Zhuang were different from those in Han subjects, but the genotypic frequencies in Hei Yi Zhuang subjects were not different from those in Han subjects. There was no significant correlation between polymorphism of the lipoprotein lipase gene at the Pvu II site and serum lipid levels in the two ethnic groups. Clin Chem Lab Med 2006;44:1416–21.

Background : Knowledge about the presence of intact cardiac troponin T (cTnT) and/or its immunoreactive fragments is of great value for the interpretation of cTnT clearance from the circulation. Until now there has been a lot of controversy about cTnT fragmentation. To provide an answer to this controversy, we investigated fragmentation of cTnT with size-exclusion chromatography (SEC), and confirmed our data using mass spectrometry. Methods : A highly purified human cTnT standard, characterised using mass spectrometry as a single peak of 34,377 Da and using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) as a single immunoreactive band (37 kDa), was incubated in serum for 0, 24 and 48h at 37°C and analysed using SEC. A troponin TIC complex standard, used in an earlier study, was also investigated. Results : We demonstrated that, because of its rod-like shape, the molecular weight of cTnT cannot be estimated from SEC using the molecular weight of globular proteins as a reference. The Stokes radius of intact cTnT was calculated to be 33.7Å. Incubation of both cardiac troponin standards in troponin-free serum resulted in a time-dependent decrease in intact cTnT and a simultaneous increase in smaller immunoreactive fragments (13.4 and 22.4Å). Conclusions : cTnT has a Stokes radius of 33.7Å. Compared with globular calibrator proteins, intact cTnT elutes earlier than expected based solely on its molecular weight. For non-globular or uncharacterised proteins, Stokes radii should be used for correct interpretation of SEC data. By doing so, we were able to clearly demonstrate cTnT fragments. Clin Chem Lab Med 2006;44:1422–7.

Background : Point-of-care testing for C-reactive protein (CRP) may be helpful in differentiating viral from bacterial infection. Such a device should give results comparable to laboratory testing. The aim was to evaluate two point-of-care CRP tests (Nycocard and QuikRead) in febrile children in general practice, compared to a reference immunoturbidimetric assay. Methods : A cross-sectional study was carried out of febrile children aged 3months to 6years presented to a general practice out-of-hours service. Children were visited at home where blood was taken for tests, within 24h after presentation. The Nycocard test was performed at home, whereas the QuikRead and reference test were performed in the laboratory. Results : A total of 76 children were enrolled. All three CRP tests were performed in 59 children. The mean difference between the reference test and Nycocard and QuikRead was 0.6 and −6.1mg/L, respectively. The slope of the Passing-Bablok regression was 0.95 (95% CI 0.9–1.0) and 0.83 (95% CI 0.81–0.85) for the Nycocard and QuikRead tests, respectively. Conclusions : Up to a concentration of 160mg/L, the Nycocard test correlated well with the reference test, while the QuikRead test underestimated concentrations above 60mg/L. The Nycocard test seems a good candidate for CRP point-of-care testing in general practice. Clin Chem Lab Med 2006;44:1428–32.

Background : Identification of porphyrias relies on the measurement of different porphyrins in urine, feces and plasma. Separation of porphyrin isomers is essential for the differential diagnosis of some porphyrias. Method : Separation of naturally occurring porphyrins was achieved on a Chromolith RP-18 column with fluorimetric detection using a methanol/ammonium acetate gradient mobile phase. Fecal and plasma porphyrins were extracted with acetonitrile and water at different pH values. Results : Eight porphyrins including protoporphyrin eluted within 20min with good resolution of each of the I and III positional isomer pairs for standards, urine and plasma, and within 50min for feces. Improvement of the extraction method for fecal and plasmatic porphyrins resulted in high recovery (up to 89%) and reliable quantification of protoporphyrin. Conclusions : The present RP-HPLC method is specific and efficient for routine analysis of porphyrins in human urine, feces and plasma. Clin Chem Lab Med 2006;44:1433–40.

Background : Measurement of late-night salivary cortisol concentrations is increasingly used as a screening test in suspected Cushing's syndrome. Cortisol concentrations are typically extremely low in late-night samples and discordant assay-specific reference ranges have been reported. Therefore, the aim of our study was to assess the analytical performance of the first automated cortisol immunoassay specified for salivary measurements and to establish late-night sampling reference-range data for this test. Methods : Salivary cortisol was measured using the Roche Cobas Cortisol assay (Roche Diagnostics). Five salivary pools in different concentration ranges were used to assess the inter-assay imprecision of this test in a two-centre evaluation protocol including two reagent lots. Linearity was tested by serial dilution. Salivary samples were obtained at 23:00h from 100 apparently healthy volunteers using a commercially available salivary sampling device (Salivette, Sarstedt). A subset of 20 samples was used for method comparison with isotope dilution liquid chromatography-tandem mass spectrometry. Results : Inter-assay coefficients of variation (n=20) between 11.6% and 40.4% were found for mean cortisol concentrations between 12.9 and 2.6nmol/L, with an estimated functional sensitivity of approximately 5.0nmol/L. The test also gave linear results in the lowest concentration range between 1.0 and 8.3nmol/L. Mean late-night salivary cortisol of 5.0nmol/L was found for healthy individuals; the absolute range was 1.4–16.7nmol/L, and the 95th percentile was 8.9nmol/L. Substantially lower concentrations were found with isotope dilution LC-MS/MS compared to immunoassay results (mean concentrations 1.8 and 4.4nmol/L, respectively). Conclusions : The automated assay investigated was found to offer acceptable analytical performance in the very low concentration range required for late-night salivary cortisol, despite a very short turn-around time. Using this assay, late-night salivary cortisol concentrations below 8.9nmol/L are typically found in healthy volunteers. Clin Chem Lab Med 2006;44:1441–5.

Background : Most of the commonly used markers of chronic alcohol abuse reflect alcohol hepatotoxicity; however, such abuse is deleterious to the kidneys as well. Combined use of serum markers of liver origin and urinary markers of kidney origin may be of diagnostic advantage. Methods : The study was performed in 73 male alcoholics undergoing detoxification and 36 male alcoholics who had maintained abstinence for ≥6weeks. Factor analysis, discriminant analysis and receiver operating characteristic (ROC) analysis were used to assess the discriminative power of two urinary markers of alcohol nephrotoxicity, namely β-N-acetylhexosaminidase (Hex, EC 3.2.1.52) and alanine aminopeptidase (EC 3.4.11.2), and of three serum markers of alcohol hepatotoxicity, namely aspartate aminotransferase (EC 2.6.1.1), alanine aminotransferase (EC 2.6.1.2) and γ-glutamyltransferase (GGT, EC 2.3.2.2), and of their quantitative combinations. Results : The discriminative power of the urinary markers matched that of the serum markers. Hex and GGT appeared to be the best for discriminating the study groups. Their combination given by the equation G&H=0.62×ln(GGT)+0.72×ln(Hex) showed excellent discriminative ability (ROC area under the curve 0.92) that was significantly higher than that of any single marker in this report, indicating superior diagnostic accuracy of the compound marker. Conclusions : Kidney-derived urinary markers, particularly Hex, can complement or replace, if necessary, serum markers of chronic alcohol abuse that relate to alcohol hepatotoxicity. The compound marker proposed seems a promising tool for the monitoring and perhaps detection of chronic alcohol abuse and warrants further studies. Clin Chem Lab Med 2006;44:1446–52.

Background : Cholestasis, roughly divided into intrahepatic and extrahepatic forms, is a clinical challenge. Extrahepatic cholestasis, characterized by dilated bile ducts, is caused by either a bile duct stone or stricture, with stricture most often related to a malignancy. The aim of the present study was to analyze the value of common liver function tests in separating patients with malignant bile duct strictures from those with stones. Methods : All consecutive patients admitted for endoscopic retrograde cholangiopancreatography (ERCP) were included in the study population if a bile duct stricture related to a malignancy was found by ERCP (n=103) or if a bile duct stone was successfully extracted during ERCP, thus confirming the diagnosis of a stone (n=109). Plasma alkaline phosphatase, γ-glutamyltransferase, alanine aminotransferase and bilirubin values were determined in the morning before ERCP. Results : Plasma bilirubin (p<0.001), alkaline phosphatase (p<0.001) and alanine aminotransferase (p=0.040) levels were significantly higher in patients with malignant bile duct strictures than in those with bile duct stones. In addition, γ-glutamyltransferase levels seemed to be higher in patients with malignant strictures than in those with stones, although the difference did not reach statistical significance (p=0.053). In receiver operating characteristic analyses, bilirubin proved to be the best laboratory test in differentiating patients (p=0.001 vs. alkaline phosphatase, p<0.001 vs. alanine aminotransferase and p<0.001 vs. γ-glutamyltransferase). With a plasma bilirubin cutoff value of 145μmol/L, four out of five patients were categorized correctly. Conclusions : Plasma bilirubin seems to be the best liver function test in distinguishing patients with malignant bile duct strictures from those with bile duct stones. This routine test should receive more attention in clinical decision-making than has previously been given. Clin Chem Lab Med 2006;44:1453–6.

Background : Insulin resistance and hyperinsulinemia have been reported among patients with hypertension. However, little is known about insulin sensitivity in subjects with prehypertension. The aim of this study was to assess whether the metabolic characteristics of insulin resistance syndrome are present in prehypertensive subjects. Methods : Plasma fasting glucose, lipid profile, glycated hemoglobin, fructosamine and insulin concentrations were evaluated in 35 prehypertensive subjects and in 30 healthy controls. Results : Prehypertensive subjects had significantly higher levels of plasma insulin and triglycerides compared with normotensive subjects. The level of high-density lipoprotein cholesterol was significantly lower in prehypertensive subjects compared with controls. There was no significant difference in total cholesterol and low-density lipoprotein cholesterol levels. The levels of glycated hemoglobin and fructosamine were also significantly higher in prehypertensive subjects compared with controls. Plasma insulin levels were positively correlated with systolic and diastolic blood pressure in prehypertensive subjects. Similarly, plasma insulin was significantly positively correlated with triglyceride and negatively correlated with high-density lipoprotein cholesterol. Conclusions : The present study indicates that prehypertensive non-diabetic subjects have higher insulin resistance and protein glycation compared to normotensive subjects, which may contribute to the pathogenesis of prehypertension. Clin Chem Lab Med 2006;44:1457–61.

Background: The glycemia decision limits recommended by WHO/ADA for type 2 diabetes detection are derived from clinical signs in advanced stages of the disease. Since insulin secretion patterns and sensitivitity are impaired at the beginning of type 2 diabetes, this stage may be better suited to identify decision limits with higher diagnostic efficiency than those currently applied. Methods: Oral glucose tolerance tests were performed in 300 subjects. Glucose concentrations were measured at 30-min intervals in venous plasma, venous blood and capillary blood. Insulin concentrations in venous plasma, an insulin sensitivity index and body mass index were used to indicate a type 2 diabetic state. A multiple logistic regression procedure was “trained” using only subjects “clearly” considered to be non-diseased or diseased based on an oral glucose tolerance test according to WHO criteria. This insulin algorithm was applied to the whole study group, leading to definitive classification into the non-diseased or the diseased group. This a posteriori classification was used to identify cutoff values with the highest diagnostic efficiency. Results: The diagnostic efficiency was significantly higher when decision limits lower than the WHO recommendations for glucose concentrations were applied in a preselected subpopulation and in all three sample systems tested, e.g., 9.49mmol/L (171mg/dL) for venous plasma and 8.94mmol/L (161mg/dL) for capillary blood in the 2-h post-load state. The optimized and WHO 2-h cutoff values corresponded to a disease prevalence of 28% and ∼5% (20% in the fasting state), respectively. Diagnostic efficiency was higher in the 2-h post-load than in the fasting state. Combining fasting values with 2-h post-load values did not further improve the diagnostic efficiency. Glucose concentrations determined from capillary blood were as efficient as those from venous blood or plasma. The number of diabetic subjects detected differed considerably between capillary blood and venous plasma for the WHO/ADA cutoff values, but not for the optimized cutoff values. Conclusions: The efficiency of type 2 diabetes diagnosis can be improved by optimizing cutoff values according to disease prevalence. Unexpectedly, the optimized 2-h post-load cutoff was lower for capillary blood than for venous plasma. It is proposed to identify a risk group e.g., by characteristics of the metabolic syndrome in which the 2-h post-challenge concentration is determined using lower cut-off values than presently recommended. Clin Chem Lab Med 2006;44:1462–71.

Background : Total tau (T-tau) and β-amyloid (1-42) (Aβ 1-42 ) levels in cerebrospinal fluid (CSF) can differentiate Alzheimer's disease (AD) from normal aging or depressive pseudo-dementia. Differential diagnosis from dementia with Lewy bodies (DLB) in clinical settings is difficult. Methods : The analytical performance of the INNOTEST ® PHOSPHO-TAU (181P) assay was validated in terms of selectivity, sensitivity, specificity, precision, robustness, and stability. Clinical utility of the assay alone, or combined with T-tau and Aβ 1-42 , for discrimination of AD (n=94) from patients suffering from DLB (n=60) or from age-matched control subjects (CS) (n=60) was assessed in a multicenter study. Results : CSF concentrations of tau phosphorylated at threonine 181 (P-tau 181P ) in AD was significantly higher than in DLB and CS. Discriminant analysis, a classification tree, and logistic regression showed that P-tau 181P was the most statistically significant single variable of the three biomarkers for discrimination between AD and DLB. Conclusions : P-tau 181P quantification is a robust and reliable assay that may be useful in discriminating AD from DLB. Clin Chem Lab Med 2006;44:1472–80.

Background : Cystatin C is increasingly used as a glomerular filtration marker, but so far only a few companies produce most of the cystatin C reagents suited for turbidimetry or nephelometry use in clinical laboratories. Methods : We studied different protocols for measuring cystatin C on an Architect ci8200 system using cystatin C reagents from Dako (Glostrup, Denmark). The results were compared with those obtained with Dade Behring reagents (Deerfield, IL, USA) on a BN ProSpec system. Results : Differences in assay protocol on the same instrument with the Dako reagent yielded an up to 50% difference in glomerular filtration rate calculated from the cystatin C results when analyzing patient samples, but had no effect on the results for controls. There were also significant differences regarding linearity and kinetics between samples and controls/calibrators. Conclusions : The results indicate different reactivity of the Dako antibodies against calibrators and controls in comparison with patient samples, highlighting the importance of using controls and calibrators that do not differ from patient samples. Clin Chem Lab Med 2006;44:1481–5.

In current clinical practice, plasma and blood glucose are used interchangeably with a consequent risk of clinical misinterpretation. In human blood, glucose is distributed, like water, between erythrocytes and plasma. The molality of glucose (amount of glucose per unit water mass) is the same throughout the sample, but the concentration is higher in plasma, because the concentration of water and therefore glucose is higher in plasma than in erythrocytes. Different devices for the measurement of glucose may detect and report fundamentally different quantities. Different water concentrations in the calibrator, plasma, and erythrocyte fluid can explain some of the differences. Results for glucose measurements depend on the sample type and on whether the method requires sample dilution or uses biosensors in undiluted samples. If the results are mixed up or used indiscriminately, the differences may exceed the maximum allowable error for glucose determinations for diagnosing and monitoring diabetes mellitus, thus complicating patient treatment. The goal of the International Federation of Clinical Chemistry and Laboratory Medicine, Scientific Division, Working Group on Selective Electrodes and Point of Care Testing (IFCC-SD-WG-SEPOCT) is to reach a global consensus on reporting results. The document recommends reporting the concentration of glucose in plasma (in the unit mmol/L), irrespective of sample type or measurement technique. A constant factor of 1.11 is used to convert concentration in whole blood to the equivalent concentration in plasma. The conversion will provide harmonized results, facilitating the classification and care of patients and leading to fewer therapeutic misjudgments. Clin Chem Lab Med 2006;44:1486–90.

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. Clin Chem Lab Med 2006;44:1491–4.