Plasma Renin Activity, LC/MS/MS
Also known as: Renin, PRA
Use
Measurement of plasma renin activity (PRA) by LC‑MS/MS is useful in evaluating and screening patients for secondary causes of hypertension, including primary aldosteronism and congenital adrenal hyperplasia. It informs the aldosterone‑to‑renin ratio and aids differential diagnosis in endocrinologic evaluation of blood pressure disorders. PRA may also be used to monitor therapy in congenital adrenal hyperplasia with mineralocorticoid replacement therapy. ([findlabtest.com](https://www.findlabtest.com/lab-test/blood-tests-for-heart-disease/plasma-renin-activity-lc-ms-ms-quest-16846?utm_source=openai))
Special Instructions
This test typically requires a single blood draw into an EDTA (lavender‑top) tube. Patients should ideally collect a mid‑morning sample after being upright (sitting, standing, or walking) for at least 2 hours, then seated for 5–15 minutes prior to draw. Avoid hemolysis and plasma separator tubes. Patient preparation may include avoiding mineralocorticoid receptor antagonists for several weeks prior. Specimen should be frozen for transport. ([laboratoryalliance.com](https://www.laboratoryalliance.com/tests/display/2855?utm_source=openai))
Limitations
Specimens with gross hemolysis, lipemia, thawed plasma, or collected in plasma separator tubes are unacceptable. Insufficient volume or improper handling (e.g., failure to freeze promptly) may result in specimen rejection. LC/MS/MS performance characteristics are lab‑validated and not FDA cleared. ([laboratoryalliance.com](https://www.laboratoryalliance.com/tests/display/2855?utm_source=openai))
Methodology
Mass Spectrometry
Biomarkers
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1‑2 mL blood to yield ~0.8 mL plasma
Minimum Volume
0.5‑0.8 mL plasma
Container
Lavender (EDTA) tube
Collection Instructions
Collect mid‑morning after ≥2 hours upright, then sit 5‑15 minutes before draw; spin at room temp and freeze plasma; do not use plasma separator tube
Patient Preparation
Avoid mineralocorticoid receptor antagonists; moderate sodium diet preferred; fasting overnight preferred in some protocols
Storage Instructions
Freeze plasma; transport frozen
Causes for Rejection
Gross hemolysis, gross lipemia, plasma separator tube usage, thawed specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 24 hours |
| Frozen | 28 days |