Test Directory

Renin Activity, Plasma

Updated Test Information:

Test Description

Synonym(s)

PRA (Plasma Renin Activity)

Test ID

PRA

General Information

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)

Specimen Type

Plasma

Specimen Requirements

Lavender

Additional Processing Details

1. Draw blood in a chilled syringe from a patient in a seated position; place specimenin 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 plasmato plastic vial. (If a refrigerated
centrifuge is unavailable, chill the centrifuge carriers. Centrifuge specimen for< or =5 minutes, then promptly transfer plasma.)
5. Immediately freeze plasma.

Stability

Plasma EDTA Frozen 14 days

Unacceptable Specimen Conditions

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Limitations

Angiotensin converting enzyme (ACE) inhibitors have the potential to "falsely elevate" PRA. Therefore, in a patient
treated with an ACE-inhibitor, the findings of a detectable PRA level or a low SA:PRA ratio do not exclude the
diagnosis of primary aldosteronism. In addition, a strong predictor for primary aldosteronism is a PRA level
undetectably low in a patient taking an ACE-inhibitor.

Methodology

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

Estimated TAT

2 days

Testing Schedule

Monday through Friday; 1 p.m.

CPT Code(s)

84244

Minimum Sample Volume

1.15 mL

Reference Range

Age	Mean	Range
0-2 years	4.6 ng/mL/hour	1.4-7.8 ng/mL/hour
3-5 years	2.5 ng/mL/hour	1.5-3.5 ng/mL/hour
6-8 years	1.4 ng/mL/hour	0.8-2.0 ng/mL/hour
9-11 years	1.9 ng/mL/hour	0.9-2.9 ng/mL/hour
12-17 years	1.8 ng/mL/hour	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)
> or =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)
< or =0.6-4.3 ng/mL/hour (range)
> or =40 years: 1.0 ng/mL/hour (mean)
< or =0.6-3.0 ng/mL/hour (range)

Performing Lab

Mayo

LOINC Code(s)

2915-7