Thrombin generation in different commercial sodium citrate blood tubes.

BACKGROUND: This study aimed to verify whether blood drawn into six different commercial coagulation tubes generated comparable results of thrombin generation. METHODS: Blood was sequentially collected from 20 healthy subjects into different brand and draw volume 3.2% sodium citrate tubes (4.3 mL Sarstedt, 3.0 mL Greiner, 2.7 mL Becton Dickinson, 2.0 mL Kima, 1.8 mL Sarstedt and 1.0 mL Greiner). Thrombin generation was measured in plasma with the fully-automated ST Genesia analyzer using the weakest trigger (STG-BleedScreen). RESULTS: Different values of lag time (LT), time to reach thrombin peak (TP), thrombin peak height (PH) and endogenous thrombin potential (ETP) were commonly found in different tubes. Thrombin generation was the lowest in 4.3 mL Sarstedt tubes and the highest in 1.0 mL Greiner tubes. Other tubes displayed intermediate values. In multiple comparisons, LT was significantly different in 6/15 cases (40%), whilst PH, TP and ETP were significantly different in 14/15 (93%), 13/15 (87%) and 13/15 (87%) cases. The mean percent bias of LT, PH, TP and ETP ranged between -6% and +1%, -27% and +116%, -22% and +8%, and between -18% and +65%. The intra-assay imprecision of LT, PH, TP and ETP was exceeded in 0/15 (0%), 13/15 (87%), 6/15 (40%) and 13/15 (87%) comparisons. The correlation of LT, PH, TP and ETP values in different tubes ranged between 0.718-0.971, 0.570-0.966, 0.725-0.977 and 0.101-0.904. CONCLUSIONS: Blood collection for thrombin generation assays requires local standardization using identical tubes for brand and draw volume, and reference ranges calculated according to type of tubes.

The Role of Red Blood Cell Distribution Width for Predicting 1-year Mortality in Patients Admitted to the Emergency Department with Severe Dyspnoea.

BACKGROUND: Universally accepted and validated instruments for predicting the outcome of patients presenting to the emergency department (ED) with severe dyspnoea do not exist so far, nor are they regularly used by the emergency physicians. This study hence aimed to establish whether red blood cell distribution width (RDW) may be a predictive parameter of 1-year mortality in a population of patients admitted to the ED with severe dyspnoea attributable to different underlying disorders. METHODS: We retrospectively evaluated all the patients undergoing arterial blood gas analysis for severe dyspnoea (irrespective of the cause) during admission to ED of University Hospital of Verona from September 1, 2014 to November 31, 2014. RESULTS: The final study population consisted of 287 patients for whom complete clinical and laboratory information was available. Overall, 36 patients (12.5%) died after a 1-year follow-up. The RDW value was found to be considerably increased in patients who deceased during the follow-up compared to those who survived (17.2% versus 14.8%; p<0.001). In both univariate and multivariate analyses, the RDW value was found to be a significant predictor of 1-year mortality. In particular, patients with RDW ≥ 15.0% displayed a 72% increased risk of 1-year mortality after multiple adjustments. CONCLUSIONS: The measurement of RDW, a very simple and inexpensive laboratory parameter, may represent an important factor for predicting medium-term mortality in patients presenting to the ED with severe dyspnoea.

Assessment of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and platelet count as predictors of long-term outcome after R0 resection for colorectal cancer.

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and platelet count (PC) were shown to be prognostic in several solid malignancies. We analysed 603 R0 resected patients to assess whether NLR, PLR and PC correlate with other well-known prognostic factors and survival of patients with colorectal cancer (CRC). Receiver operating characteristic (ROC) curve analysis was performed to define cut-off values for high and low ratios of these indices. Univariate and multivariate analysis were used to determine the prognostic value of NLR, PLR and PC for overall and cancer-related survival. The distribution of NLR, PLR and PC in CRC patients was compared with 5270 healthy blood donors. The distribution of NLR, PLR and PC was significantly different between CRC patients and controls (all p < 0.05). A significant but heterogeneous association was found between the main CRC prognostic factors and high values of NLR, PLR and PC. Survival appeared to be worse in patients with high NLR with cancers in AJCC/UICC TNM Stages I-IV; nonetheless its prognostic value was not confirmed for cancer-related survival in multivariate analysis. After stratification of patients according to AJCC/UICC TNM stages, high PC value was significantly correlated with overall and cancer-related survival in TNM stage IV patients.

Epidemiological association between uric acid concentration in plasma, lipoprotein(a), and the traditional lipid profile.

BACKGROUND: Elevated levels of uric acid in serum (SUA) or plasma (PUA) are increasingly related to cardiovascular disease. It is unclear whether they are independent risk factors or simply markers, reflecting association with other traditional risk factors. METHODS: We retrospectively assessed results of a lipid profile, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, total cholesterol to HDL-C ratio (TC/HDL-C), the atherogenic index of plasma (AIP), and lipoprotein(a) (Lp[a]), in a large cohort of unselected adult outpatients. RESULTS: Hyperuricemic men displayed significantly increased values of triglycerides and AIP when compared with men with normal PUA levels. In hyperuricemic women, significant differences were observed for HDL-C, triglycerides, TC/HDL-C, and AIP compared with women with normal PUA levels. The percentage of patients with unfavorable values was statistically higher for triglycerides and AIP in hyperuricemic men; for HDL-C, triglycerides, TC/HDL-C, and AIP in hyperuricemic women. In multivariable linear regression analysis triglycerides, AIP, and TC/HDL-C were independently associated with PUA in women, whereas no significant association was observed in men. CONCLUSION: PUA measurement might be advisable in patients to identify those at increased risk of cardiovascular disease (CVD) who might benefit from further triage and intervention.

Multicenter evaluation of the hemolysis index in automated clinical chemistry systems.

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.

Comparison of creatinine-based estimations of glomerular filtration rate in endurance athletes at rest.

BACKGROUND: Several creatinine-based estimates of the glomerular filtration rate (GFR) have been advocated as reliable alternatives to the urinary clearance of exogenous filtration markers. The Cockcroft-Gault (C-G) equation requires a body weight parameter, which was not included in the Modification of Diet in Renal Disease (MDRD) Study and the Mayo Clinic Quadratic Equation (MCQE) formulas. However, there is little information on the lifestyle influences on these equations, especially the intensity and the type of physical activity. METHODS: We evaluated the differences in the GFR, as estimated by the MDRD, MCQE and C-G equations, in 60 professional male cyclists at rest and 60 healthy sedentary matched controls. RESULTS: Professional cyclists had significantly lower body weight, body mass index and serum creatinine concentration than healthy sedentary individuals. We also observed a significantly higher MDRD-estimated GFR in athletes than in controls (119 mL/min/1.73 m2 vs. 104 mL/min/1.73 m2, p<0.001), whereas the GFR values estimated by both the MCQE (137 vs. 135, p=0.128) and C-G (127 vs. 127, p=0.490) formulas did not differ significantly. As compared to the MDRD values, the mean GFR calculated by the MCQE and C-G formulas was overestimated by 29% and 23% in the sedentary population, and by 17% and 7% in athletes, respectively. A lower bias was observed when comparing C-G with MCQE-estimated values in both the sedentary [mean: -5%, 95% confidence interval (CI): -32% to 22%] and athlete (mean: -6%, 95% CI: -41% to 29%) populations. The correlation among the different equations in healthy sedentary individuals was always significant, whereas the only significant association in the athletes was that between MCQE and C-G values. CONCLUSIONS: The results of this study attest that the three most widely used creatinine-based formulas produce significant variations in the estimated GFR in a population of endurance athletes at rest. Probably, the use of C-G or MCQE formulas might be more suitable in this context, as they globally appear more robust against variations of the training regimen.

National survey on critical values reporting in a cohort of Italian laboratories.

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.