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Angiotensin I Converting Enzyme (ACE) Activity, Capillary Blood

Published: August 9, 2026Updated: August 16, 2026

A legacy test that measures angiotensin I converting enzyme (ACE) activity in capillary blood. Results may be affected by ACE-inhibitor medication.

Quick summary

["This blood test measures ACE enzyme activity, which can be affected by ACE-inhibitor medicines and certain medical conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
77450-5
Short code
Deprecated C+A+P+LxB>A.th+A CT.Angio W c
Synonyms
Deprecated C+A+P+LxB>A.th+A CT.Angio W c
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct-angio
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test measures the activity of angiotensin I converting enzyme, also called ACE, in a small capillary blood sample. The test name is considered legacy or deprecated, so the specimen and method may vary by laboratory.

Why might I need this test?

ACE activity may be measured when a clinician is evaluating a condition that can alter ACE levels, such as sarcoidosis or another granulomatous disorder. It may also be used as part of a broader clinical assessment.

How is the test performed?

A small amount of blood is collected by fingerstick or another capillary collection method. The laboratory then measures ACE enzyme activity using its established laboratory method.

How do I prepare for the test?

No special preparation is usually required for capillary blood collection. Tell your clinician if you take an ACE inhibitor, because this medicine can lower measured ACE activity; do not stop prescribed medication without medical advice.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ACE activity, capillary blood

Frequently asked questions

What does ACE activity measure?
ACE activity measures the functional activity of an enzyme involved in the angiotensin system, which helps regulate blood pressure, fluid balance, and blood vessel function.
Why is a capillary blood sample used?
A capillary sample requires only a small amount of blood, often collected by fingerstick. The laboratory should provide specific collection instructions because this is a legacy test with potentially different specimen requirements.
Can medications affect the result?
Yes. ACE inhibitors, including lisinopril and enalapril, can substantially lower ACE activity. Tell your clinician about all medicines and supplements before the test, but do not stop prescribed treatment on your own.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy