ACE

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Also known as: SACE (Serum Angiotensin Converting Enzyme)
Formal name: Angiotensin Converting Enzyme

At a Glance

Why Get Tested?

To help diagnose and monitor sarcoidosis and to help distinguish it from other diseases which show similar symptoms

When to Get Tested?

When you have granulomas (masses of inflammatory cells) that create small bumps under the skin, a lingering cough, red watery eyes and/or other symptoms suggestive of sarcoidosis. When you have active sarcoidosis in order to follow its progress

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Angiotensin converting enzyme (ACE) is an enzyme which helps regulate blood pressure. It converts angiotensin I (an inactive protein) to angiotensin II which causes arteries to contract, making them temporarily narrower and increasing the pressure of the blood flowing through them. ACE is produced throughout the body, but is present in especially high amounts within the lungs.  It is normally found at a high concentration in the bloodstream of those less than 20 years of age, and will usually then drop to lower concentrations in healthy adults.

Increased amounts of ACE are sometimes produced by cells found at the outside borders of granulomas. Granulomas are a classic feature of sarcoidosis, a disorder (the cause of which is unknown) that often affects the lungs but may also affect many other body organs including the eyes, skin, nerves, liver, and heart. About 50-80% of patients with active sarcoidosis will have elevated concentrations of ACE in their bloodstream that will rise and fall as the severity of the disease changes. Granulomas, fibrosis, and  an elevated ACE concentration may also be seen in infections such as leprosy and tuberculosis. The granulomas form around the invading bacteria in these infections and can also form around irritant particles in poisons such as beryllium, asbestos, and silicon.

How is the sample collected for testing?

A blood sample is taken by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.