Sensitivity and specificity of radioisotope renography in renovascular hypertension

Effective drug therapy for hypertension modifies the urgency of establishing a diagnosis of renal arterial stenosis. The cost of establishing a diagnosis must be considered with other factors in determining the usefulness of renography in renovascular hypertension. Recently published studies estimate the cost effectiveness of this procedure based on some data from a cooperative study of renal vascular hypertension. The small but costly incidence of false positives contributes significantly to the total cost of patient screening. Careful attention to technical details that are presented here could reduce false positives without sacrificing the true positives. However, even with increased specificity economic considerations would indicate limiting a screening program to younger patients or those in whom a drug regimen is unsuccessful.