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Renin, Direct

Test Codes

EPIC: LAB7056, Beaker: XRD, Warde: DREN

Department

Send Outs

Instructions

Patient preparation prior to specimen collection:

• Angiotensin Converting Enzyme (ACE) Inhibitors should be avoided, if possible, for at least 48 hours prior to collection.
• Sprironlactone (Aldactone) should be discontinued 4-6 weeks prior to testing.
• Patient should be on a normal sodium diet.

Specimen Collection Criteria

Collect: One Lavender-top EDTA tubes.

Critical frozen. Place specimen on ice and immediately deliver to the Laboratory for processing. Separate specimens must be submitted when multiple tests are ordered.

Physician Office/Draw Specimen Preparation

Critical frozen. Centrifuge to separate plasma from cells. Transfer plasma to a plastic transport tube and freeze (-20°C/-4°F or below) immediately.

Preparation for Courier Transport

Transport: 1.5 mL plasma, frozen (-20°C/-4°F or below). (Minimum: 1.0 mL)

Rejection Criteria

• Grossly icteric specimens.
• Grossly lipemic specimens.
• Hemolyzed specimens.
• Heparin plasma specimens.
• Serum specimens.
• Specimens not collected and processed as indicated.
• Dark blue trace element EDTA.
• Non-frozen samples.

In-Lab Processing

Critical frozen. Centrifuge to separate plasma from cells. Transfer plasma to a plastic transport tube and freeze (-20°C/-4°F or below) immediately.

Transport: 1.5 mL plasma, frozen (-20°C/-4°F or below). (Minimum: 1.0 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Warde Medical Laboratory, Ann Arbor, MI.

Performed

Monday, Wednesday, Thursday.
Results available in 2-6 days.

Reference Range

3.1 - 57.1 pg/mL.

Test Methodology

Chemilumnescence.

Interpretation

By report.

Clinical Utility

The determination of renin is useful for the investigation of primary and secondary aldosteronism. The direct renin assay can be used alone or in combination with aldosterone to obtain an aldosterone to renin ratio (1). An aldosterone/direct renin ratio of >3.0, according to one study (2) has a sensitivity of 90% and a specificity of 100%. Alternatively, when the direct renin concentration is less than 12.6 pg/mL and the aldosterone concentration is greater than 15.0 ng/dL, the sensitivity and specificity is 98%.(3).

Reference

1. Funder JW, Carey RM, et.al., Endocrine Society Practice Guideline, JCEM, (2016) 101 (5): 1889-1916
2. Lonati 6, Bassani N,et.al., Measurement of plasma renin concentration instead of plasma renin activity decreases the positive aldosterone-to-renin ratio tests in treated patients with essential hypertension. J. Hypertens 2014 Mar,32 (3): 627-34.
3. Valcour A, Soldo J, et al., Analytical Performance of Immunoassays in a Suspect Primary Aldosteronism Population. Poster presentation, ICE/ENDO 2014; June 21-24 in Chicago, IL, USA.

CPT Codes

84244

Contacts

Last Updated

11/6/2023