Key result
Blood sample processing at room temperature versus +4 °C for 30 minutes yielded highly correlated results for direct renin (r=0.9994) and plasma renin activity (r=0.8297).
Why the study?
Does blood sample processing temperature and tube type affect the measurement of plasma renin activity, direct renin concentration, and aldosterone?
Observational (n=47)
Does blood sample processing temperature and tube type affect the measurement of plasma renin activity, direct renin concentration, and aldosterone?
Effect estimate: r = 0.9994 for DRC, r = 0.8297 for PRA
Blood samples for direct renin concentration and plasma renin activity can be processed at room temperature for up to 30 minutes without significantly affecting results, though aldosterone levels are higher in plasma than serum.
May simplify renin sample handling in clinical labs; leaves open standardization for aldosterone and longer delays.
INTRODUCTION: Performing measurements of plasma renin activity (PRA) or direct renin concentration (DRC) and aldosterone concentration, we should be well informed about requirements concerning blood sample processing. MATERIAL AND METHODS: Forty-seven patients had blood collected in the supine and upright positions. Blood was withdrawn into two EDTA2K tubes and one with clot activator. One EDTA2K tube was cooled at +4 °C and centrifuged at +4 °C whereas the other was prepared at room temperature. PRA and DRC were measured by radioimmunoassay (RIA) and radioimmunometry (IRMA), respectively, in both cooled and not cooled plasma samples, and aldosterone was measured by RIA in not cooled plasma and in serum. RESULTS: In all the groups, with low, medium, and high values of PRA and direct renin, the temperature of sample processing within 30 minutes had no marked influence on the final result (correlation coefficient for renin was 0.9994, and for PRA, 0.8297). The measured concentrations of aldosterone also showed high correlation (r = 0.9790) but were markedly higher in plasma. CONCLUSION: The measurements of DRC, and to a lesser extent PRA, were similar regardless of temperature condition during the 20-30 minutes necessary for blood sample processing. Aldosterone concentrations in plasma vs serum samples appeared to be markedly higher.
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Glinicki et al. (2013) reported an observational. Blood sample processing at room temperature vs. Cooled at +4 °C was evaluated on Plasma renin activity (PRA) and direct renin concentration (DRC) (r = 0.9994 for DRC, r = 0.8297 for PRA). Blood sample processing at room temperature versus +4 °C for 30 minutes yielded highly correlated results for direct renin (r=0.9994) and plasma renin activity (r=0.8297).
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