The presence of clinical clues increases the predictive value of scree
ning tests for renovascular hypertension; these include abrupt onset o
f hypertension before age 30 or after age 55, severe hypertension, acc
elerated or malignant hypertension, hypertension refractory to a tripl
e-drug regimen, moderate hypertension with diffuse vascular disease, a
n epigastric bruit, moderate hypertension with unexplained azotemia, a
nd azotemia induced by an angiotensin-converting enzyme inhibitor. Cap
topril renography and duplex ultrasonography are clinically useful scr
eening tools, but wide variation in accuracy exists among institutions
. Magnetic resonance angiography may emerge as an effective clinical t
est.