Plasma renin activity was found transiently elevated in association with the occurrence of renal infarction in three patients (one with proven infarction and two with probable infarction). In these patients, there was good control of physical activity and sodium intake primarily due to their original diseases, and there were no conceivable factors responsible for the transient rise of plasma renin activity other than the episode of renal infarction. Since serum enzyme determinations used as diagnostic aids for renal infarction, such as transaminase or lactic dehydrogenase, lack organ specificity and since renin is specific for the kidney, the determination of the plasma renin activity fulfills the problem of organ specificity and may serve as a much more specific diagnostic aid than other serum enzyme determinations.
Arakawa K, Torii S, Naito S, Minohara A, Uemura N, Nakamura M. Plasma Renin Activity as a More Specific Diagnostic Aid for Renal Infarction. Arch Intern Med. 1970;125(5):830-834. doi:10.1001/archinte.1970.00310050068007