Plasma renin activity: effect of temperature during blood processing.

Plasma renin activity may be affected by temperature during the processing of blood samples (loss of activity or cryoactivation). We measured plasma renin activity on samples maintained at room temperature up to 240 min. No significant change was found in comparison with samples maintained at 0 degrees C; similarly, no cryoactivation was observed when routine freezing procedures were employed instead of instant freezing.