Liquid chromatography-Tandem Mass Spectrometry
Investigation of primary and secondary aldosteronism
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)
4 - 10 days
Draw in a chilled syringe, into a prechilled tube, from a patient in a seated position. Immediately place the EDTA tube in an ice bath. Refrigerate while centrifuging, and immediately aliquot and freeze the plasma, within 30 minutes.
Angiotensin converting enzyme (ACE) inhibitors have the potential to "falsely elevate" PRA. Therefore, in a patient treated with an ACE-inhibitor, the findings of a detectable PRA level or a low SA/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.
Not useful for determination of plasma renin concentration.
This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held and assayed after the radioactivity has sufficiently decayed. This will result in a test delay.