Gian Luca Salvagno

Relation between red blood cell distribution width and inflammatory biomarkers in a large cohort of unselected outpatients.

CONTEXT A strong independent association has been recently observed between elevated red blood cell distribution width (RDW) and increased incidence of cardiovascular events. OBJECTIVE To assess whether RDW is associated with plasma markers of inflammation since the mechanism(s) underlying this association remain unknown. DESIGN We retrospectively analyzed results of RDW, hemoglobin, mean corpuscular volume, ferritin, high-sensitivity C-reactive protein (hsCRP), and erythrocyte sedimentation rate (ESR) in a large cohort of unselected adult outpatients who were consecutively referred by general practitioners for routine medical check-up. RESULTS Cumulative results of RDW and other factors were retrieved from the database of our laboratory information system for 3845 adult outpatients during a 3-year period. When participants were grouped according to RDW quartiles, there were strong, graded increases of ESR and hsCRP (P < .001), both parameters being up to 3-fold higher in the fourth versus the first quartile. Accordingly, the percentages of those with hsCRP greater than 3 mg/L (from 28% to 63%; P < .001) and ESR greater than 40 mm/h (from 8% to 40%; P < .001) increased steadily across RDW quartiles. In multivariable regression analysis, ESR and hsCRP predicted RDW independently of age, sex, mean corpuscular volume, hemoglobin, and ferritin. CONCLUSIONS To our knowledge, our study demonstrates for the first time a strong, graded association of RDW with hsCRP and ESR independent of numerous confounding factors. If confirmed in future follow-up studies, this association might provide a rationale to introduce the easy, inexpensive RDW in algorithms for cardiovascular risk prediction.

Influence of hemolysis on routine clinical chemistry testing.

Abstract Background: Preanalytical factors are the main source of variation in clinical chemistry testing and among the major determinants of preanalytical variability, sample hemolysis can exert a strong influence on result reliability. Hemolytic samples are a rather common and unfavorable occurrence in laboratory practice, as they are often considered unsuitable for routine testing due to biological and analytical interference. However, definitive indications on the analytical and clinical management of hemolyzed specimens are currently lacking. Therefore, the present investigation evaluated the influence of in vitro blood cell lysis on routine clinical chemistry testing. Methods: Nine aliquots, prepared by serial dilutions of homologous hemolyzed samples collected from 12 different subjects and containing a final concentration of serum hemoglobin ranging from 0 to 20.6g/L, were tested for the most common clinical chemistry analytes. Lysis was achieved by subjecting whole blood to an overnight freeze-thaw cycle. Results: Hemolysis interference appeared to be approximately linearly dependent on the final concentration of blood-cell lysate in the specimen. This generated a consistent trend towards overestimation of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, creatine kinase (CK), iron, lactate dehydrogenase (LDH), lipase, magnesium, phosphorus, potassium and urea, whereas mean values of albumin, alkaline phosphatase (ALP), chloride, γ-glutamyltransferase (GGT), glucose and sodium were substantially decreased. Clinically meaningful variations of AST, chloride, LDH, potassium and sodium were observed in specimens displaying mild or almost undetectable hemolysis by visual inspection (serum hemoglobin <0.6g/L). The rather heterogeneous and unpredictable response to hemolysis observed for several parameters prevented the adoption of reliable statistic corrective measures for results on the basis of the degree of hemolysis. Conclusion: If hemolysis and blood cell lysis result from an in vitro cause, we suggest that the most convenient corrective solution might be quantification of free hemoglobin, alerting the clinicians and sample recollection.

Preanalytical quality improvement: from dream to reality

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.

The ROMA (Risk of Ovarian Malignancy Algorithm) for estimating the risk of epithelial ovarian cancer in women presenting with pelvic mass: is it really useful?

Abstract Background: The study is aimed at evaluating the performance of the predictive model ROMA (Risk of Ovarian Malignancy Algorithm), which utilizes the combination of human epididymis protein 4 (HE4) and CA125 values to assess the risk of epithelial ovarian cancer (EOC) in women with a pelvic mass. Methods: One hundred and four women diagnosed with a pelvic mass (55 EOC and 49 benign cases) and scheduled to have surgery were enrolled, along with 49 healthy females. Preoperative serum concentrations of HE4 and CA125 were measured. Separate logistic regression algorithms ROMA for pre-menopausal and post-menopausal women were used to categorize patients into low- and high-risk groups for EOC. The area under the curve (AUC), sensitivity and specificity were calculated for HE4, CA125 and ROMA for the diagnosis of ovarian cancer using receiver operating characteristic (ROC) analysis. Results: The median CA125 and HE4 serum concentrations were significantly higher among EOC patients than in healthy females (both p<0.05) and those with a benign mass (both p<0.05). The pre-menopausal group included 36 benign cases (29 of which were classified by ROMA as low-risk with a specificity of 80.6%; 95% CI: 64.0%–91.8%), and 15 EOC (eight of which were classified by ROMA as high-risk, with a sensitivity of 53.3%; 95% CI: 26.6%–78.7%). The post-menopausal group enclosed 13 benign cases (11 of which were classified by ROMA as low-risk with a specificity of 84.6%; 95% CI: 54.6%–98.0%), and 40 EOC (33 of which were classified by ROMA as high-risk with a sensitivity of 82.5%; 95% CI: 67.2%–92.7%). In the pre-menopausal group, the AUC was 0.64 (p=0.12, 95% CI: 0.44–0.83) for CA125, 0.77 (p=0.003, 95% CI: 0.62–0.92) for HE4 and 0.77 (p=0.002, 95% CI: 0.63–0.92) for ROMA. In the post-menopausal group, the AUC was 0.84 (p=0.0003, 95% CI: 0.73–0.94) for CA125, 0.94 (p<0.0001, 95% CI: 0.88–0.99) for HE4 and 0.92 (p<0.0001, 95% CI: 0.85–0.99) for ROMA. Conclusions: The ROMA is a simple scoring system which shows excellent diagnostic performance for the detection of EOC in post-menopausal women, but not in pre-menopausal women. Moreover, the dual marker combination of HE4 and CA125 (ROMA) does not show better performance than HE4 alone.

Red blood cell distribution width: A simple parameter with multiple clinical applications

Abstract The red blood cell distribution width (RDW) is a simple and inexpensive parameter, which reflects the degree of heterogeneity of erythrocyte volume (conventionally known as anisocytosis), and is traditionally used in laboratory hematology for differential diagnosis of anemias. Nonetheless, recent evidence attests that anisocytosis is commonplace in human disorders such as cardiovascular disease, venous thromboembolism, cancer, diabetes, community-acquired pneumonia, chronic obstructive pulmonary disease, liver and kidney failure, as well as in other acute or chronic conditions. Despite some demographic and analytical issues related to the routine assessment that may impair its clinical usefulness, an increased RDW has a high negative predictive value for diagnosing a variety of disorders, but also conveys important information for short- and long-term prognosis. Even more importantly, the value of RDW is now being regarded as a strong and independent risk factor for death in the general population. Although it has not been definitely established whether an increased value of RDW is a risk factor or should only be considered an epiphenomenon of an underlying biological and metabolic imbalance, it seems reasonable to suggest that the assessment of this parameter should be broadened far beyond the differential diagnosis of anemias. An increased RDW mirrors a profound deregulation of erythrocyte homeostasis involving both impaired erythropoiesis and abnormal red blood cell survival, which may be attributed to a variety of underlying metabolic abnormalities such as shortening of telomere length, oxidative stress, inflammation, poor nutritional status, dyslipidemia, hypertension, erythrocyte fragmentation and alteration of erythropoietin function. As such, the aim of this article is to provide general information about RDW and its routine assessment, to review the most relevant implications in health and disease and give some insights about its potential clinical applications.

Relationship between red blood cell distribution width and kidney function tests in a large cohort of unselected outpatients

Objective. A strong, independent, association has recently been shown between higher red blood cell distribution width (RDW) and the risk of all‐cause death and cardiovascular events. However, the mechanism(s) underlying this association remains unclear. Since impaired kidney function is a well‐known risk factor for cardiovascular disease, we assessed whether RDW is associated with decreased kidney function. Material and methods. We cross‐sectionally assessed results of RDW, haemoglobin, main corpuscular volume (MCV) and serum creatinine levels in a large cohort of unselected adult outpatients consecutively referred by general practitioners for routine medical check‐up. Glomerular filtration rate (GFR) was estimated using the abbreviated Modification of Diet in Renal Disease (MDRD) equation. Results. Cumulative results of RDW, creatinine and other variables were retrieved from the database of our Laboratory Information System for 8,585 adult outpatients over a 3‐year period. When participants were grouped according to RDW quartiles, there was a strong, graded, decrease in estimated GFR levels (ranging from 87±18 to 81±32 mL/min/1.73 m2; p<0.0001). Accordingly, the percentage of participants with estimated GFR<60 mL/min/1.73 m2 increased steadily across RDW quartiles (from 5 % to 19 %; p<0.0001). In logistic regression analysis, lower estimated GFR strongly predicted higher RDW levels (p<0.0001) independently of age, gender, MCV and haemoglobin values. Conclusions. Our findings suggest that there is an inverse, graded, association between RDW and kidney function tests in a large cohort of unselected adult outpatients.

Quality Standards for Sample Collection in Coagulation Testing

Preanalytical activities, especially those directly connected with blood sample collection and handling, are the most vulnerable steps throughout the testing process. The receipt of unsuitable samples is commonplace in laboratory practice and represents a serious problem, given the reliability of test results can be adversely compromised following analysis of these specimens. The basic criteria for an appropriate and safe venipuncture are nearly identical to those used for collecting blood for clinical chemistry and immunochemistry testing, and entail proper patient identification, use of the correct technique, as well as appropriate devices and needles. There are, however, some peculiar aspects, which are deemed to be particularly critical when collecting quality specimens for clot-based tests, and these require clearer recognition. These include prevention of prolonged venous stasis, collection of nonhemolyzed specimens, order of draw, and appropriate filling and mixing of the primary collection tubes. All of these important preanalytical issues are discussed in this article, and evidence-based suggestions as well as recommendations on how to obtain a high-quality sample for coagulation testing are also illustrated. We have also performed an investigation aimed to identify variation of test results due to underfilling of primary blood tubes, and have identified a clinically significant bias in test results when tubes are drawn at less than 89% of total fill for activated partial thromboplastin time, less than 78% for fibrinogen, and less than 67% for coagulation factor VIII, whereas prothrombin time and activated protein C resistance remain relatively reliable even in tubes drawn at 67% of the nominal volume.

Recommendations for detection and management of unsuitable samples in clinical laboratories

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. Clin Chem Lab Med 2007;45:728–36.

The role of ethylenediamine tetraacetic acid (EDTA) as in vitro anticoagulant for diagnostic purposes.

Abstract Anticoagulants are used to prevent clot formation both in vitro and in vivo. In the specific field of in vitro diagnostics, anticoagulants are commonly added to collection tubes either to maintain blood in the fluid state for hematological testing or to obtain suitable plasma for coagulation and clinical chemistry analyses. Unfortunately, no universal anticoagulant that could be used for evaluation of several laboratory parameters in a sample from a single test tube is available so far. Ethylenediamine tetraacetic acid (EDTA) is a polyprotic acid containing four carboxylic acid groups and two amine groups with lone-pair electrons that chelate calcium and several other metal ions. Calcium is necessary for a wide range of enzyme reactions of the coagulation cascade and its removal irreversibly prevents blood clotting within the collection tube. Historically, EDTA has been recommended as the anticoagulant of choice for hematological testing because it allows the best preservation of cellular components and morphology of blood cells. The remarkable expansion in laboratory test volume and complexity over recent decades has amplified the potential spectrum of applications for this anticoagulant, which can be used to stabilize blood for a variety of traditional and innovative tests. Specific data on the behavior of EDTA as an anticoagulant in hematology, including possible pitfalls, are presented. The use of EDTA for measuring cytokines, protein and peptides, and cardiac markers is described, with an outline of the protection of labile molecules provided by this anticoagulant. The use of EDTA in proteomics and in general clinical chemistry is also described in comparison with other anticoagulants and with serum samples. Finally, the possible uses of alternative anticoagulants instead of EDTA and the potential use of a universal anticoagulant are illustrated. Clin Chem Lab Med 2007;45:565–76.

Multicenter evaluation of the hemolysis index in automated clinical chemistry systems

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. Clin Chem Lab Med 2009;47:934–9.