The captopril challenge test (CCT) is a non-invasive medical test that measures the change in renin

Renin

Renin , also known as an angiotensinogenase, is an enzyme that participates in the body's renin-angiotensin system -- also known as the Renin-Angiotensin-Aldosterone Axis -- that mediates extracellular volume , and arterial vasoconstriction...

 plasma

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

-levels in response to administration of captopril

Captopril

Captopril is an angiotensin-converting enzyme inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first ACE inhibitor developed and was considered a breakthrough both because of its novel mechanism of action and also because of the...

, an angiotensin converting enzyme inhibitor. It is used to assist in the diagnosis of renal artery stenosis

Renal artery stenosis

Renal artery stenosis is the narrowing of the renal artery, most often caused by atherosclerosis or fibromuscular dysplasia. This narrowing of the renal artery can impede blood flow to the target kidney...

. It is not generally considered a useful test for children, and more suitable options are available for adult cases.

Procedure

Plasma concentration of renin is measured prior to and following the administration of captopril. The CCT is considered positive if the renin levels increase substantially or the baseline renin level is abnormally high.

In adults

CCT in adults is known to have high sensitivity, but a low specificity.

Subtraction angiography is considered a more suitable test for renal artery stenosis in adults.

See also

Contrast with:

• captopril suppression test
  Captopril suppression test
  The captopril suppression test is a non-invasive medical test that measures plasma levels of aldosterone.Aldosterone production is suppressed by captopril through the renin-angiotensin-aldosterone system. CST results are used to assist in the diagnososis of primary aldosteronism ....
  
   used to diagnose primary aldosteronism