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Test Code PRA Renin Activity, Plasma

Reporting Name

Renin Activity, P

Useful For

Investigation of primary aldosteronism (eg, adrenal adenoma/carcinoma and adrenal cortical hyperplasia) and secondary aldosteronism (renovascular disease, salt depletion, potassium loading, cardiac failure with ascites, pregnancy, Bartter syndrome)

 

Not useful for determination of plasma renin concentration.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Plasma EDTA


Specimen Required


Patient Preparation: The plasma renin activity cannot be interpreted if the patient is being treated with spironolactone (Aldactone). Spironolactone should be discontinued for 4 to 6 weeks before testing.

Collection Container/Tube: Chilled, lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 2 mL

Collection Instructions:

1. Draw blood in a chilled syringe from a patient in a seated position; place specimen in a chilled, lavender-top (EDTA) tube; and mix.

2. Alternatively, draw blood directly in a chilled, lavender top (EDTA) tube.

3. Immediately place EDTA tube into an ice-water bath until thoroughly cooled.

4. Refrigerate specimen during centrifugation and immediately transfer plasma to plastic vial. (If a refrigerated centrifuge is unavailable, chill the centrifuge carriers. Centrifuge specimen for ≤5 minutes, then promptly transfer plasma.)

5. Immediately freeze plasma.

Additional Information: See Renin-Aldosterone Studies in Special Instructions for further information.


Specimen Minimum Volume

1.15 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma EDTA Frozen 14 days

Special Instructions

Reference Values

0-2 years: 4.6 ng/mL/hour (mean)* Range: 1.4-7.8 ng/mL/hour

3-5 years: 2.5 ng/mL/hour (mean)* Range: 1.5-3.5 ng/mL/hour

6-8 years: 1.4 ng/mL/hour (mean)* Range: 0.8-2.0 ng/mL/hour

9-11 years: 1.9 ng/mL/hour (mean)* Range: 0.9-2.9 ng/mL/hour

12-17 years: 1.8 ng/mL/hour (mean)* Range: 1.2-2.4 ng/mL/hour

Mean data not standardized as to time of day or diet. Infants were supine, children sitting.

 

Na-depleted, upright (peripheral vein specimen)

18-39 years: 10.8 ng/mL/hour (mean)

2.9-24.0 ng/mL/hour (range)

≥40 years: 5.9 ng/mL/hour (mean)

2.9-10.8 ng/mL/hour (range)

 

Na-replete, upright (peripheral vein specimen)

18-39 years: 1.9 ng/mL/hour (mean)

≤0.6-4.3 ng/mL/hour (range)

≥40 years: 1.0 ng/mL/hour (mean)

≤0.6-3.0 ng/mL/hour (range)

*Stalker HP, Holland NH, Kotchen JM, Kotchen TA: Plasma renin activity in healthy children. J Pediatr 1976;89:256-258

Day(s) and Time(s) Performed

Monday through Friday; 1 p.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

84244

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PRA Renin Activity, P 2915-7

 

Result ID Test Result Name Result LOINC Value
8060 Renin Activity, P 2915-7

Clinical Information

The renal juxtaglomerular apparatus generates renin, an enzyme that converts angiotensinogen to angiotensin I. The inactive angiotensin I is enzymatically converted to the active octapeptide angiotensin II, a potent vasopressor responsible for hypertension of renal origin. Angiotensin II also stimulates the zona glomerulosa of the adrenal cortex to release aldosterone.

 

Renin secretion by the kidney is stimulated by a fall in glomerular blood pressure, by decreased sodium concentration at the macula densa at the distal tubule, or by stimulation of sympathetic outflow to the kidney, such as in renal vascular diseases.  

Interpretation

A high ratio of serum aldosterone (SA) in ng/dL to plasma renin activity (PRA) in ng/mL per hour, is a positive screening test result, a finding that warrants further testing. A SA:PRA ratio ≥20 and SA of ≥15 ng/dL indicates probable primary aldosteronism.

 

Renal disease, such as unilateral renal artery stenosis, results in elevated renin and aldosterone levels. Renal venous catheterization may be helpful. A positive test is a renal venous renin ratio (affected:normal) above 1.5.

 

See Renin-Aldosterone Studies in Special Instructions.

Clinical Reference

1. Young WF Jr: Primary aldosteronism: A common and curable form of hypertension. Cardiol Rev 1999;7:207-214

2. Young WF Jr: Pheochromocytoma and primary aldosteronism: diagnostic approaches. Endocrinol Metab Clin North Am 1997;26:801-827

Analytic Time

2 days

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross OK

Icterus

Mild OK; Gross OK

Other

NA

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Portions of this test are covered by patents held by Quest Diagnostics

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

General Request Form (T239) http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf

Cardiovascular Test Request Form (T724) (http://www.mayomedicallaboratories.com/it-mmfiles/cardiovascular-request-form.pdf)