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Test Code RENINACT Renin Activity, Plasma

Performing Laboratory



Liquid chromatography/mass spectrometry (LC/MS-MS).

Reference Values



Range (ng/mL/hr)

0 to 11 m


1 to 3 y


4 to 5 y


6 to 10 y


11 to 15 y


>15 y



Test Classification and CPT Coding


Computer Interface Code

PDM #5900321

Specimen Requirements

Container/Tube: Lavender tube(EDTA)

Specimen: 2 mL plasma (0.8 min)

Transport Temperature: Frozen Plasma


It is critical that the plasma be transferred and frozen as quickly as possible to prevent cryoactivation of protein to renin (which results in falsely elevated renin levels)


Patient Preparation:

In order to facilitate interpretation of test results, the patient should be taken off medications for at least three weeks prior to sample collection. Dietary sodium levels during the period prior to testing can affect renin levels. Sodium restriction tends to cause an increase in renin activity, while supplementation can result in lower values. A 24-hour urine sodium determination from a sample collected on the day before a renin test can be used to assess sodium intake. Expected renin activity levels for various levels of urinary sodium excretion are provided. Renin activity determination without the concurrent urine sodium measurement can still provide useful information if the clinician verifies that the patient has been on a normal sodium diet. Since patient posture prior to collection affects renin levels, it is recommended that the patient be ambulatory for at least 30 minutes before blood collection.1 If inpatients are physically able, they should be asked to ambulate for 30 minutes before blood is drawn for renin activity. Reference intervals are provided for patients who have ambulated for at least 30 minutes prior to collection (upright patients). Reference intervals are also provided for patients on a normal sodium diet who are unable to ambulate (supine patients).


Cause for Rejection: Non-Frozen sample;non-separated sample;non-EDTA plasma; gross icterus.

Used for

Measurement of renin activity is useful in the differential diagnosis of individuals with hypertension. Renin levels will be elevated in patients with hypertension due to renal artery stenosis (ie, renovascular hypertension). Measurement of renin activity can also be useful in the diagnosis of primary aldosteronism. Patients with secondary aldosteronism tend to have low renin levels. Renin can also be used to assess the adequacy of steroid substitution in patients with adrenal insufficiency. Renin activity will be normal in patients with adequate supplementation and will be elevated when steroid substitution is inadequate.