Serum ACE (Angiotensin-Converting Enzyme)
Angiotensin-converting enzyme (ACE) is produced by vascular endothelial cells and by macrophages in granulomas. Serum ACE is elevated in sarcoidosis — a systemic granulomatous disease — in about 60% of patients, and is sometimes used as a supportive marker. It is not sensitive or specific enough to diagnose or rule out sarcoidosis on its own, but in a patient with compatible clinical features, a very high ACE strengthens the clinical suspicion and tracks disease activity over time.
Reference Ranges
Male
8 – 65
U/L
Female
8 – 65
U/L
Child
8 – 65
U/L
Higher in children
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low ACE is usually not clinically meaningful. ACE inhibitor medications (enalapril, ramipril, lisinopril, perindopril) suppress ACE levels — patients should stop these for 1–2 weeks before testing if sarcoidosis is being evaluated. Low ACE also occurs in hypothyroidism and some chronic illnesses.
What High Levels Mean
Elevated ACE supports sarcoidosis in the right clinical setting (bilateral hilar lymphadenopathy, pulmonary infiltrates, uveitis, skin lesions, hypercalcemia). It also rises in other granulomatous diseases (tuberculosis, leprosy, histoplasmosis, berylliosis), hyperthyroidism, diabetes, liver disease, and Gaucher disease — so it is not specific. Sarcoidosis is a clinical-pathological diagnosis; tissue biopsy showing non-caseating granulomas is usually required.
Frequently Asked Questions
Is ACE level enough to diagnose sarcoidosis?
No. Sarcoidosis is diagnosed by: compatible clinical picture, biopsy-proven non-caseating granulomas, and exclusion of alternative causes (especially tuberculosis, which in India is the crucial differential diagnosis). Serum ACE is supportive but neither sensitive (40% false negatives) nor specific enough to stand alone. Bronchoscopy with biopsy, chest CT, and sometimes PET imaging are the main diagnostic tools.
Can ACE track disease activity in sarcoidosis?
In some patients yes — rising ACE often parallels active inflammation and falling ACE parallels treatment response. However, ACE does not change reliably in all patients, and normalization does not always mean clinical remission. Clinical features, imaging, and organ-specific assessments (pulmonary function tests, eye exam) remain central.
What is the Indian consideration for ACE testing?
Tuberculosis is the single most important alternative diagnosis to sarcoidosis in India — both produce hilar lymphadenopathy, pulmonary infiltrates, and even granulomas on biopsy. ACE is elevated in both. Every suspected sarcoidosis case in India needs thorough TB workup (sputum for AFB, GeneXpert, tissue AFB stain and culture) before starting immunosuppression, because treating misdiagnosed TB with steroids can cause disseminated disease.
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mg/dLThis information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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