Serum Angiotensin-Converting Enzyme (sACE) Activity

What Is Angiotensin-Converting Enzyme (ACE)?

Angiotensin-converting enzyme (ACE) is an enzyme that helps control blood pressure and fluid balance in your body. It converts a protein called angiotensin I into angiotensin II, which narrows blood vessels and raises blood pressure. ACE also breaks down a substance called bradykinin, which helps regulate fluid balance. Abnormal ACE levels may indicate conditions affecting the lungs, lymph nodes, or other systems.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like chronic cough, shortness of breath, or swelling, which could suggest conditions like sarcoidosis, lymphangioleiomyomatosis (LAM), or other lung or lymphatic diseases. It may also be used in research or specialized diagnostic contexts.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum (the liquid part without clotting factors). This serum is tested for ACE activity.

What Does the Test Result Mean?

Results are not typically provided in a standard numeric range for general clinical use, as ACE activity can vary based on conditions like pregnancy, smoking, or certain medications. Your healthcare provider will interpret the result in the context of your symptoms and medical history.