Stability of direct renin concentration and plasma renin activity in EDTA whole blood and plasma at ambient and refrigerated temperatures from 0 to 72 hours.

Samples collected for plasma renin activity and direct renin concentration should be transported as whole blood to optimise stability. After sample processing, plasma can be kept at room temperature for up to 24 h for direct renin concentration, however, for determination of plasma renin activity separated plasma should be analysed or frozen as soon as possible.