Table 3.

Physiologic Diagnostic Tests Used to Diagnose ARAS39–41

Test	Advantages	Disadvantages
Plasma Renin Activity	-it can be used in procedural setting to predict which individuals with ARAS will have improvement in their resistant hypertension after PTRAS	- affected by physiological parameters (blood volume, sodium load, unilateral versus bilateral renal disease, age, race, sex and comorbidities) which can alter the circulating levels of renin -the test’s sensitivity is 57% and specificity is 66%
Captopril Renography	- provides functional data with regards to GFR reduction with ARAS with angiotensin converting enzyme inhibitor (ACE-I) compared to the increase GFR in contralateral side -measures the plasma aldosterone concentration (PAC), plasma renin concentration (ARC) and plasma renin activity (PRA) -Diagnosis of renovascular hypertension made by PAC/ARC >40 or PAC/PRA >200 -sensitivity of the test is 74% while the specificity is 59%	-it cannot specify anatomical location of renal artery lesion -not a reliable test in those with poor renal function and bilateral renal disease
Bilateral Renal Vein Renin Assay	-the renal vein renin ratio is the renin level of the ischemic kidney compared to the contralateral kidney which allows selection of individuals with hypertension and ARAS who may benefit from interventions -in 90% of the situations these individuals will respond to treatment	-high false positives and negatives, both are 67% -difficult to differentiate hypertensive individuals with unilateral and bilateral ARAS and many of them will have essential hypertension rather than renin-mediated therefore necessitating the use of additional studies (doppler ultrasound and catheter based renal arteriography)