The Renin test in EDTA plasma is a laboratory test used to evaluate levels of the hormone renin in the blood, which plays a key role in regulating blood pressure and fluid balance in the body. A blood sample is collected in a tube containing EDTA, an anticoagulant, to ensure the sample is preserved. Renin is a hormone produced by the kidneys that helps regulate the renin-angiotensin-aldosterone system, directly affecting blood pressure and fluid volume. This test helps doctors diagnose blood pressure disorders, such as secondary hypertension, and assess kidney and adrenal gland function. By measuring renin levels, it is possible to determine whether treatment adjustments or additional testing are needed.