S-ACE (Serum Angiotensin Converting Enzyme) is an enzyme that plays a central role in the body's renin-angiotensin system, where it converts angiotensin I to the biologically active form angiotensin II. This is crucial for blood pressure regulation and fluid balance. Elevated levels of S-ACE are primarily seen in sarcoidosis, an inflammatory disease in which granuloma formation in the lungs and other organs can increase the production of ACE. Therefore, the analysis is often used as a supporting biomarker in the diagnosis and follow-up of sarcoidosis.
S-ACE is produced in several tissues, including the lungs, kidneys and vascular endothelium, but the level in the blood can be affected by inflammatory diseases and certain drugs. Elevated S-ACE values can be seen in other granulomatous diseases as well as in certain metabolic and autoimmune conditions.
Why is S-ACE analysis performed?
A blood test for S-ACE is primarily used to:
- Investigate and monitor sarcoidosis, especially in cases of lung involvement.
- Differentiate sarcoidosis from other granulomatous diseases, such as tuberculosis and berylliosis.
- Assess disease activity and response to treatment in patients with sarcoidosis.
- Evaluate certain hypertension and kidney diseases, where the renin-angiotensin system may be affected.
When might an analysis of S-ACE be relevant?
The blood test for S-ACE is used in healthcare to evaluate inflammatory diseases, primarily sarcoidosis. It may be relevant for:
- Suspected sarcoidosis – with symptoms such as persistent cough, shortness of breath, fatigue and lymph node enlargement.
- Treatment follow-up – S-ACE can be used to monitor the effect of corticosteroid treatment in sarcoidosis.
- Investigation of granulomatous diseases – for example tuberculosis and berylliosis.
- Assessment of renal involvement – with suspicion of the renin-angiotensin system’s influence on blood pressure and fluid balance.
Interpretation of S-ACE test results
- Normal levels: Indicates the absence of active granulomatous inflammation.
- Elevated levels: Often seen in active sarcoidosis but can also occur in other granulomatous or inflammatory diseases.
- Low levels: May be caused by treatment with ACE inhibitors or kidney-related factors affecting enzyme activity.
It is important to note that S-ACE is not a specific marker for sarcoidosis and should always be interpreted in combination with other diagnostic methods, such as chest X-ray, serum calcium and inflammation parameters.
Reference range for S-ACE
Reference values for S-ACE vary between laboratories, but a common upper reference limit is:
Elevated S-ACE values should always be evaluated by the treating physician in conjunction with other clinical findings.