Gian Cesare Guidi

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.

Preanalytical variability: the dark side of the moon in laboratory testing.

Abstract Remarkable advances in instrument technology, automation and computer science have greatly simplified many aspects of previously tedious tasks in laboratory diagnostics, creating a greater volume of routine work, and significantly improving the quality of results of laboratory testing. Following the development and successful implementation of high-quality analytical standards, analytical errors are no longer the main factor influencing the reliability and clinical utilization of laboratory diagnostics. Therefore, additional sources of variation in the entire laboratory testing process should become the focus for further and necessary quality improvements. Errors occurring within the extra-analytical phases are still the prevailing source of concern. Accordingly, lack of standardized procedures for sample collection, including patient preparation, specimen acquisition, handling and storage, account for up to 93% of the errors currently encountered within the entire diagnostic process. The profound awareness that complete elimination of laboratory testing errors is unrealistic, especially those relating to extra-analytical phases that are harder to control, highlights the importance of good laboratory practice and compliance with the new accreditation standards, which encompass the adoption of suitable strategies for error prevention, tracking and reduction, including process redesign, the use of extra-analytical specifications and improved communication among caregivers.

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.

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.

Risk management in the preanalytical phase of laboratory testing.

Abstract The clinical laboratory is no longer its own limited ecosystem, as it is increasingly integrated with patient care, assisting diagnosis, monitoring therapies and predicting clinical outcomes. Although efforts and resources are continuously focused to achieve a satisfactory degree of analytical quality, there is clear evidence that the preanalytical phase is much more vulnerable to uncertainties and accidents, which can substantially influence patient care. Most errors within the preanalytical phase 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 in vitro hemolysis, clotting, insufficient volume, wrong container, contamination and misidentification. A reliable approach to overcome this problem entails prediction of accidental events (exhaustive process analysis, reassessment and rearrangement of quality requirements, dissemination of operating guidelines and best-practice recommendations, reduction of complexity and error-prone activities, introduction of error-tracking systems and continuous monitoring of performances), an increase in and diversification of defenses (application of multiple and heterogeneous systems to identify non-conformities), and a decrease in vulnerability (implementation of reliable and objective detection systems and causal relation charts, education and training). This policy, which requires integration between requirements and design, full commitment and interdepartmental cooperation, should make laboratory activity more compliant to the inalienable paradigm of total quality in the testing process. Clin Chem Lab Med 2007;45:720–7.

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.

Effect of CPAP on Blood Pressure in Patients With OSA/Hypopnea: A Systematic Review and Meta-analysis

BACKGROUND CPAP is considered the therapy of choice for OSA, but the extent to which it can reduce BP is still under debate. We undertook a systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify the effect size of the reduction of BP by CPAP therapy compared with other passive (sham CPAP, tablets of placebo drug, conservative measures) or active (oral appliance, antihypertensive drugs) treatments. METHODS We searched four different databases (MEDLINE, EMBASE, Web of Science, and the Cochrane Library) with specific search terms and selection criteria. RESULTS From 1,599 articles, we included 31 RCTs that compared CPAP with either passive or active treatment. In a random-effects meta-analysis vs passive treatment (29 RCTs, 1,820 subjects), we observed a mean±SEM net difference in systolic BP of 2.6±0.6 mm Hg and in diastolic BP of 2.0±0.4 mm Hg, favoring treatment with CPAP (P<.001). Among studies using 24-h ambulatory BP monitoring that presented data on daytime and nighttime periods, the mean difference in systolic and diastolic BP was, respectively, 2.2±0.7 and 1.9±0.6 mm Hg during daytime and 3.8±0.8 and 1.8±0.6 mm Hg during nighttime. In meta-regression analysis, a higher baseline apnea/hypopnea index was associated with a greater mean net decrease in systolic BP (beta±SE, 0.08±0.04). There was no evidence of publication bias, and heterogeneity was mild ( I2, 34%-36%). CONCLUSIONS Therapy with CPAP significantly reduces BP in patients with OSA but with a low effect size. Patients with frequent apneic episodes may benefit the most from CPAP.

Serum paraoxonase activity is decreased in uremic patients

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.

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.

Severe impairment of antioxidant system in human hepatoma

Catalase (CAT), glutathione‐peroxidase (GSH‐Px) activity and reduced glutathione content (GSH) were measured in patients who had hepatocellular carcinoma, and values compared with those of normal liver and liver adjacent to neoplastic tissue. The results showed a remarkable reduction of CAT in tumor and corresponding tumor‐free tissue (P < 0.001 and P < 0.02, respectively). All neoplastic samples had a significant lower activity of CAT than the corresponding adjacent tumor‐free tissue (P < 0.05). The GSH‐Px activity of tumor tissue also was lower than normal (P < 0.001) but similar to that of adjacent tissue. No correlation was noted between the two enzyme activities. Glutathione content was extremely low in tumor (P < 0.001) and even in tumor‐free tissue (P < 0.05) when compared with normal liver. In all cases the content of GSH in neoplastic tissue was lower than that of the corresponding tumor‐free tissue (P < 0.05). Whereas in normal liver the activity of GSH‐Px was positively correlated with the content of GSH, in the neoplastic tissue such a relationship disappeared. All these findings suggest that the antioxidant system of hepatocellular carcinoma cell is severely impaired.