Ensure that the patient has NOT been receiving any medications known to affect the renin/aldosterone system.
Ensure that the patient is on a normal sodium diet (100-200 meq/day) for at least 3 days before collecting samples.
Collect the sample in the midmorning after patient has been sitting, standing, or walking for at least 2 hours. Begin collection when patient has been seated for 5-15 minutes.
Centrifuge within 24 hours of collection and separate plasma from cells.
Label a plastic transport tube with two identifiers. Acceptable identifiers include patient’s name, date of birth, social security number, requisition number, and medical record number. Label the tube as EDTA plasma.
Transfer plasma to the tube and freeze - send this aliquot separately when multiple tests are ordered.