Test Id : PRA
Renin Activity, Plasma
Useful For
Suggests clinical disorders or settings where the test may be helpful
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)
This test is not useful for determination of plasma renin concentration.
Method Name
A short description of the method used to perform the test
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Portions of this test are covered by patents held by Quest Diagnostics
NY State Available
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Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
PRA (Plasma Renin Activity)
Specimen Type
Describes the specimen type validated for testing
Plasma EDTA
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Patient Preparation: For 4 to 6 weeks before specimen collection, spironolactone (Aldactone) should be discontinued, as plasma renin activity cannot be interpreted if the patient is being treated with spironolactone.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Chilled, lavender top (EDTA)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.8 mL
Collection Instructions:
1. Draw blood in a chilled syringe from a patient in a seated position; place specimen in a chilled, 3-mL lavender-top (EDTA) tube and mix well. Alternatively, draw blood directly in a chilled, EDTA tube.
2. Immediately place EDTA tube into an ice-water bath until thoroughly cooled.
3. Immediately centrifuge using a refrigerated centrifuge and aliquot plasma into a plastic vial.
Note: If a refrigerated centrifuge is unavailable, chill the centrifuge carriers before use. Centrifuge specimen for 5 minutes or less, then promptly aliquot plasma into a plastic vial.
4. Immediately freeze plasma.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Cardiovascular Test Request (T724)
-Renal Diagnostics Test Request (T830)
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.5 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma EDTA | Frozen | 14 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
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)
This test is not useful for determination of plasma renin concentration.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
0-2 years: 4.6 ng/mL/h (mean)* Range: 1.4-7.8 ng/mL/h
3-5 years: 2.5 ng/mL/h (mean)* Range: 1.5-3.5 ng/mL/h
6-8 years: 1.4 ng/mL/h (mean)* Range: 0.8-2.0 ng/mL/h
9-11 years: 1.9 ng/mL/h (mean)* Range: 0.9-2.9 ng/mL/h
12-17 years: 1.8 ng/mL/h (mean)* Range: 1.2-2.4 ng/mL/h
Mean data not standardized as to time of day or diet. Infants were supine, children sitting.
*Stalker HP, Holland NH, Kotchen JM, Kotchen TA. Plasma renin activity in healthy children. J Pediatr. 1976;89(2):256-258
Na-depleted, upright (peripheral vein specimen)
18-39 years: 10.8 ng/mL/h (mean)
2.9-24.0 ng/mL/h (range)
> or =40 years: 5.9 ng/mL/h (mean)
2.9-10.8 ng/mL/h (range)
Na-replete, upright (peripheral vein specimen)
18-39 years: 1.9 ng/mL/h (mean)
< or =0.6-4.3 ng/mL/hour (range)
> or =40 years: 1.0 ng/mL/h (mean)
< or =0.6-3.0 ng/mL/h (range)
Interpretation
Provides information to assist in interpretation of the test results
A high ratio of serum aldosterone (SA) in ng/dL to plasma renin activity (PRA) in ng/mL/h, is a positive screening test result, a finding that warrants further testing. A SA:PRA ratio greater than or equal to 20 and SA of greater than or equal to 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) above 1.5.
For more information see Renin-Aldosterone Studies.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Young WF Jr. Primary aldosteronism: A common and curable form of hypertension. Cardiol Rev. 1999;7(4):207-214
2. Young WF Jr. Pheochromocytoma and primary aldosteronism: diagnostic approaches. Endocrinol Metab Clin North Am. 1997;26(4):801-827. doi:10.1016/s0889-8529(05)70283-8
3. Baudrand R, Vaidya A. The low-renin hypertension phenotype: genetics and the role of the mineralocorticoid receptor. Int J Mol Sci. 2018;19(2):546. doi:10.3390/ijms19020546
Method Description
Describes how the test is performed and provides a method-specific reference
The renin in plasma is allowed to act on the plasma's endogenous substrate, angiotensinogen, producing angiotensin I. This is measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Renin activity is expressed in nanograms (ng) of angiotensin produced per mL of plasma per hour of incubation. The primary metabolite of renin activity, angiotensin I, is cleaved by converting enzyme to angiotensin II.
By inhibiting the action of converting enzyme and the angiotensinases with EDTA, dimercaprol (BAL) and 8-hydroxyquinoline, it is possible to indirectly measure the activity of renin during a controlled incubation by measuring the concentration (in ng) of angiotensin I that is generated.
It has been demonstrated that maximum renin activity occurs at a generation system pH of 5.5-6.0. Therefore, generation conditions are adjusted to this pH range.
Using the Hamilton STAR, EDTA Plasma is mixed with generation buffer in the 0 degrees C generation tray. The sample/buffer mix is transferred to a 37 degrees C generation tray. The 37 degrees C tray is incubated in a shaking waterbath for 1 hour. During that incubation time, the 0 degrees C tray has internal standard (IS) added and is crashed, then placed on a titer plate shaker for a minimum of 15 minutes. Once the hour incubation is complete, the 37 degrees C tray also has IS and crash solution added and is shaken for 15 minutes. The plates are then centrifuged and placed back on the Hamilton STAR. The supernatant layer is transferred to the designated 0 degrees C and 37 degrees C round bottom DW96 collection plates. The plates are dried down under nitrogen, reconstituted and analyzed for AngI by LC-MS/MS.
Transitions for LC-MS/MS
AngI-1 analyte: 433.1 m/z to 513.4 m/z; Internal standard: 435.1 m/z to 519.4 m/z
AngI-2 analyte: 433.1 m/z to 647.4 m/z; Internal standard: 435.1 m/z to 647.4 m/z
(Unpublished Mayo Method)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Friday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
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Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
84244
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| PRA | Renin Activity, P | 2915-7 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 8060 | Renin Activity, P | 2915-7 |