Angiotensin-Converting Enzyme
Also known as: ACE, Serum ACE
What Does Angiotensin-Converting Enzyme Measure?
Angiotensin-Converting Enzyme (ACE) is an enzyme found primarily in the lungs, kidneys, and blood vessels. A blood test measures the level of this enzyme circulating in the serum. ACE plays a central role in the renin-angiotensin-aldosterone system (RAAS), a hormonal cascade that regulates blood pressure and fluid balance by converting angiotensin I into the potent vasoconstrictor angiotensin II, and by breaking down bradykinin, a blood pressure-lowering peptide.
Why Does Angiotensin-Converting Enzyme Matter?
Measuring serum ACE levels is clinically significant primarily as a marker for sarcoidosis, a granulomatous inflammatory disease most commonly affecting the lungs and lymph nodes. Elevated ACE is found in roughly 60–80% of patients with active sarcoidosis, making it useful for diagnosis and monitoring disease activity and treatment response. Beyond sarcoidosis, abnormal ACE levels can indicate other granulomatous diseases, liver disorders, hyperthyroidism, and certain lung conditions, providing clinicians with important diagnostic clues across a range of systemic conditions.
Normal Ranges
Males
8–52 U/L (units may vary slightly by laboratory)
Females
8–52 U/L (units may vary slightly by laboratory)
Children
Varies by age; children typically have higher ACE levels than adults, ranging from 20–90 U/L in younger children
Causes of High Levels
- Sarcoidosis — the most common cause; granulomas produce excess ACE
- Gaucher's disease — a lipid storage disorder causing elevated macrophage-derived ACE
- Hyperthyroidism — increased thyroid hormone activity stimulates ACE production
- Primary biliary cholangitis (PBC) — granulomatous liver inflammation raises ACE
- Histoplasmosis or other fungal granulomatous infections
- Leprosy — chronic granulomatous bacterial infection associated with elevated ACE
Causes of Low Levels
- ACE inhibitor medications (e.g., lisinopril, enalapril) — directly suppress ACE activity
- Hypothyroidism — reduced thyroid hormone activity lowers ACE production
- Advanced chronic obstructive pulmonary disease (COPD) — loss of pulmonary endothelial cells reduces ACE
How to Improve Your Angiotensin-Converting Enzyme
Diet
- Adopt an anti-inflammatory diet rich in fruits, vegetables, and omega-3 fatty acids to support overall immune regulation
- Limit processed foods, refined sugars, and trans fats, which promote systemic inflammation that can worsen conditions like sarcoidosis
- Ensure adequate magnesium intake through foods like leafy greens, nuts, and seeds, as magnesium supports cardiovascular and enzymatic function
- Stay well-hydrated with water to support kidney function and blood pressure regulation tied to the RAAS system
- Moderate alcohol consumption, as excess alcohol stresses the liver and may exacerbate underlying granulomatous conditions
Supplements
- Omega-3 fatty acids (1–3 g/day of EPA+DHA) — may help reduce systemic inflammation in granulomatous disease
- Vitamin D (1,000–2,000 IU/day, under physician guidance) — note caution in sarcoidosis, as some patients cannot metabolize vitamin D normally and may develop hypercalcemia
- Curcumin (500–1,000 mg/day with piperine) — natural anti-inflammatory that may support immune balance
- Magnesium glycinate (200–400 mg/day) — supports cardiovascular health and blood pressure regulation
Related Biomarkers
Frequently Asked Questions
What does a high ACE level mean?
A high ACE level most commonly suggests sarcoidosis, a condition where the immune system forms clusters of inflamed cells (granulomas) in organs such as the lungs, lymph nodes, and skin. However, elevated ACE can also indicate other granulomatous diseases like Gaucher's disease, histoplasmosis, leprosy, or hyperthyroidism. A high result alone is not diagnostic — your doctor will interpret it alongside symptoms, imaging, and other blood tests.
Can ACE inhibitor medications affect my ACE blood test result?
Yes, absolutely. ACE inhibitor medications — commonly prescribed for high blood pressure and heart failure (e.g., lisinopril, enalapril, ramipril) — directly block the ACE enzyme and will significantly lower your serum ACE test result. If you are taking an ACE inhibitor, your test result will likely be artificially low and cannot be used to reliably diagnose or monitor conditions like sarcoidosis. Always inform your doctor about all medications before testing.
Is ACE testing used to diagnose sarcoidosis?
ACE is a supportive marker for sarcoidosis, not a definitive diagnostic test. While serum ACE is elevated in about 60–80% of people with active sarcoidosis, it can also be elevated in other conditions, and some sarcoidosis patients have normal ACE levels. Diagnosis typically requires a combination of clinical assessment, chest imaging (X-ray or CT scan), and often a tissue biopsy. Once diagnosed, ACE levels are particularly useful for tracking disease activity and response to treatment.