Limitations of the captopril test in the diagnosis of renovascular hypertension

The captopril test has been suggested as a sensitive and specific noninvasive tool for the diagnosis of renovascular hypertension. We applied the test to 72 consecutive hypertensive patients in whom renal artery stenosis was suspected. The test was positive in seven cases (9.7%), of whom four were true positive and three false positive. The captopril test has value in screening for renovascular hypertension, but its limitations should be recognized. False positive results are not uncommon and false negative results have been reported under certain circumstances. Nevertheless, when properly applied to appropriate patients, the test can enhance the diagnosis of renal artery stenosis.