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Background Serum samples should be centrifuged for at least 10 min at 1300-2500 × g. Changed centrifugation conditions could compromise sample quality. The objective of this study was to compare the serum quality and turnaround time (TAT) using different centrifugation conditions. Methods The study was done in four different periods (A, B, C and D) at different conditions: for 10, 5 and 7 (A, B and C, respectively) at 2876 × g, and 7 (D) min at 4141 × g. Sample quality was assessed as the proportion of samples with: (a) aspiration errors, (b) H index >0.5 g/L and (c) suppressed reports of potassium (K) due to hemolysis. TAT was calculated for emergency samples. The proportions of samples (a), (b) and (c) were compared according to period A. Results The number of aspiration errors was significantly higher in samples centrifuged at 2876 × g for 5 min (p = 0.021) and remained unchanged when centrifuged for 7 min (p = 0.066 and 0.177, for periods C and D, respectively). In periods B, C and D, the proportion of samples with hemolysis was higher than that in period A (p-values 0.039, 0.009 and 0.042, respectively). TAT differed between all periods (p < 0.001), with the lowest TAT observed for B and D. The lowest number of samples exceeding 60-min TAT was observed in period D (p = 0.011). Conclusions The integrity of serum samples is changed with different centrifugation conditions than those recommended. Our study showed that shorter centrifugation at higher force (7 min at 4141 × g) significantly decreases TAT, with unchanged proportion of samples with aspiration errors.

Background: Patients with end-stage renal disease (ESRD) and on hemodialysis (HD) are at increased risk for developing rheumatoid arthritis (RA), as a result of defective immunity. Our aim was to examine if ESRD and the length of HD treatment impact the clinical utility of antibodies to cyclic citrullinated peptides (anti-CCP) and rheumatoid factor (RF) as diagnostic tools for RA., Methods: We included 94 subjects in our study: 37 healthy volunteers and 57 patients with ESRD who had been undergoing HD for 1-12 years, and without confirmed RA. In order to test our hypothesis, we measured and correlated anti-CCP and RF as laboratory markers of RA., Results: Our study showed that there is no significant difference between values for anti-CCP (p=0.11) and RF (p=0.98) in control subjects as well as in patients undergoing HD, regardless of the length of time that patients had been undergoing HD treatment., Conclusions: Our study indicates that HD does not impair the specificity of anti-CCP and RF for RA in patients where the disease has not yet developed. Future prospective studies may show whether there is any use in determinating RF, and especially anti-CCP, as early predictors of RA in patients with ESRD who are at greater risk of developing this condition.