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22858 Renin Activity, Plasma (PRA)

Renin Activity, Plasma (PRA)
Test Code: PRASO
Synonyms/Keywords
​PRA (Plasma Renin Activity)
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 Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No  EDTA Plasma​ Chilled, EDTA Lavender Top Tubes (LTT)​ ​ 2.0 mL​ 1.15 mL​

 

Collection Processing Instructions
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 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 < or =5 minutes, then promptly transfer plasma.)
5. Immediately freeze plasma.
Specimen Stability Information
Specimen Type Temperature Time
EDTA Plasma​ Frozen 14 days​
Rejection Criteria
Gross Hemolysis
Interference

​Angiotensin converting enzyme (ACE) inhibitors have the potential to falsely elevate plasma renin activity (PRA). Therefore, in a patient treated with an ACE-inhibitor, the findings of a detectable PRA level or a low serum aldosterone 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.​

Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available
 Methodology/Instrumentation
Mayo Clinic Laboratory Monday through Friday 2-5 day​s
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Portions of this test are covered by patents held by Quest Diagnostics
Reference Lab
Mayo Clinic Laboratories
Test 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.  

Reference Range Information
Performing Location Reference Range
Mayo Clinic Laboratories
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)
> 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)
*Stalker HP, Holland NH, Kotchen JM, Kotchen TA: Plasma renin activity in healthy children. J Pediatr 1976;89:256-258
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 > or =20 and SA > or =15 ng/dL indicates probable primary aldosteronism.
 
Kidney disease, such as unilateral renal artery stenosis, results in elevated renin and aldosterone levels. Kidney venous catheterization may be helpful. A positive test is a renal venous renin ratio (affected:normal) >1.5.
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84244​ ​ ​ ​ ​
Synonyms/Keywords
​PRA (Plasma Renin Activity)
Ordering Applications
Ordering Application Description
​COM
 ​Renin Activity, Plasma (PRA)​
​Cerner ​Renin Activity, Plasma (PRA)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No  EDTA Plasma​ Chilled, EDTA Lavender Top Tubes (LTT)​ ​ 2.0 mL​ 1.15 mL​

 

Collection Processing
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 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 < or =5 minutes, then promptly transfer plasma.)
5. Immediately freeze plasma.
Specimen Stability Information
Specimen Type Temperature Time
EDTA Plasma​ Frozen 14 days​
Rejection Criteria
Gross Hemolysis
Interference

​Angiotensin converting enzyme (ACE) inhibitors have the potential to falsely elevate plasma renin activity (PRA). Therefore, in a patient treated with an ACE-inhibitor, the findings of a detectable PRA level or a low serum aldosterone 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.​

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).
Reference Range Information
Performing Location Reference Range
Mayo Clinic Laboratories
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)
> 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)
*Stalker HP, Holland NH, Kotchen JM, Kotchen TA: Plasma renin activity in healthy children. J Pediatr 1976;89:256-258
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 > or =20 and SA > or =15 ng/dL indicates probable primary aldosteronism.
 
Kidney disease, such as unilateral renal artery stenosis, results in elevated renin and aldosterone levels. Kidney venous catheterization may be helpful. A positive test is a renal venous renin ratio (affected:normal) >1.5.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available
 Methodology/Instrumentation
Mayo Clinic Laboratory Monday through Friday 2-5 day​s
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Portions of this test are covered by patents held by Quest Diagnostics
Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84244​ ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.