Angiotensin converting enzyme (ACE)
What this test measures
Angiotensin converting enzyme is an enzyme found mainly in the lining of blood vessels in the lungs, where it helps control blood pressure by converting one hormone into another. It is also made in large amounts by the clusters of immune cells (granulomas) that form in sarcoidosis, so the blood level is used as a rough marker of how much of that tissue is present.
Why doctors request it
Doctors request it mainly when looking at sarcoidosis, a condition in which clusters of immune cells form in the lungs, lymph glands, skin, eyes and elsewhere, and to follow the activity of that condition over time. It is not a routine test.
What commonly pushes it up
- Sarcoidosis, in about half to two thirds of people with active disease
- Other conditions that form granulomas, including tuberculosis and some fungal infections
- An overactive thyroid
- Diabetes, a little
- Liver disease and Gaucher disease
- Childhood and the teenage years, in the general population
- Inherited variation in the ACE gene, which sets a higher resting level in some people
What commonly pushes it down
- ACE inhibitor medicines such as ramipril and lisinopril, which lower the measured level a great deal
- Treatment of sarcoidosis with steroids
- An underactive thyroid
- Some lung cancers and severe lung disease
- Starvation and anorexia
Everyday reasons for a value outside the range
- Taking an ACE inhibitor blood pressure tablet makes the test read low and largely uninterpretable
- Inherited variation means some healthy people have a resting level above the range
- It is higher in children and teenagers
- Methods differ so much that a number from one laboratory does not map onto another's range
About the sample
No fasting needed. The laboratory needs to know whether an ACE inhibitor is being taken. In people with sarcoidosis the trend over time is more useful than one value.
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Read my report freeThis is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.