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.

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.

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.

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.

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.

Background and objectives: Subclinical primary hypothyroidism is highly prevalent in the general population, especially in the elderly. However, the prevalence of subclinical primary hypothyroidism in persons with chronic kidney disease (CKD) not requiring chronic dialysis is not well defined. Design, setting, participants, and measurements: Cross-sectional data from 3089 adult outpatients, who were consecutively referred by general practitioners for routine blood testing over the last two years, were analyzed. Glomerular filtration rate (GFR) was estimated by the abbreviated Modification of Diet in Renal Disease equation. Multivariable logistic regression was used to evaluate the independent association between prevalent subclinical primary hypothyroidism and estimated GFR. Results: Among 3089 adult participants, 293 (9.5%) had subclinical primary hypothyroidism and 277 (9%) had an estimated GFR <60 ml/min per 1.73 m². The prevalence of subclinical primary hypothyroidism increased from 7% at an estimated GFR ≥90 ml/min per 1.73 m² to 17.9% at an estimated GFR <60 ml/min per 1.73 m² (P < 0.0001 for trend). Compared with participants with an estimated GFR ≥60 ml/min per 1.73 m², those with estimated GFR <60 ml/min per 1.73 m² had an increased odds of subclinical primary hypothyroidism after adjusting for age, gender, fasting plasma glucose, total cholesterol, and triglyceride concentrations. Conclusions: These findings suggest that subclinical primary hypothyroidism is a relatively common condition (∼18%) among persons with CKD not requiring chronic dialysis, and it is independently associated with progressively lower estimated GFR in a large cohort of unselected outpatient adults.