Renin Activity, Plasma
Use
The test is particularly useful for investigating cases of primary and secondary aldosteronism, conditions that can cause hypertension, due to renal or adrenal gland abnormalities or systemic conditions like renovascular disease, salt depletion, potassium loading, heart failure with ascites, pregnancy, and Bartter syndrome. Its results help in diagnosing the root causes of hypertension in these contexts by measuring plasma renin activity, which indirectly reflects the activity of the renin-angiotensin-aldosterone system.
Special Instructions
Ensure that spironolactone treatment is discontinued 4 to 6 weeks prior to specimen collection as it can interfere with the interpretation of plasma renin activity levels. Use the Sarstedt Aliquot Tube provided, and proper specimen collection techniques as outlined are crucial to avoid confounding factors such as improper chilling and separation techniques.
Limitations
This test is limited in that it is not suitable for determining plasma renin concentration. Furthermore, ACE inhibitors can potentially elevate plasma renin activity falsely, misleading results, and necessitating cautious interpretation. Detectable PRA level or a low serum aldosterone/PRA ratio in patients treated with ACE inhibitors do not exclude primary aldosteronism diagnosis.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 2915-7
- 2915-7
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.8 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
Draw blood in a chilled syringe from a seated patient, place in a chilled EDTA tube, and mix well. Alternatively, draw directly into a chilled EDTA tube. Place tube in an ice-water bath immediately, centrifuge using a refrigerated centrifuge, and aliquot plasma into a vial before freezing.
Patient Preparation
Discontinue spironolactone (Aldactone) for at least 4 to 6 weeks before specimen collection.
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |