What is the Angiotensin Converting Enzyme Test?

The Angiotensin Converting Enzyme (ACE) test measures the amount of ACE circulating in your bloodstream. ACE is an enzyme involved in blood pressure regulation and inflammatory pathways, and abnormal levels often correlate with specific medical conditions rather than general cardiovascular issues.

Clinically, the ACE test is most frequently used as a biomarker to support the diagnosis and monitoring of sarcoidosis, a condition where clusters of inflammatory cells form in organs such as the lungs, lymph nodes, eyes or skin. Elevated ACE levels may reflect active granuloma formation, helping clinicians understand disease activity and treatment response.

While ACE is not diagnostic on its own, it plays an important role alongside imaging, clinical findings and other laboratory tests. It is a valuable piece of the puzzle for assessing inflammation-driven disorders.

Why do I need a test for Angiotensin Converting Enzyme?

You may need an ACE test if your healthcare provider suspects sarcoidosis or another granulomatous condition. ACE levels can help indicate whether inflammatory activity is occurring within the body and can be monitored over time to evaluate how well treatment is working.

ACE testing is also useful when patients present with vague but persistent symptoms, especially when imaging or clinical examination suggests lung or lymph node involvement. Tracking ACE levels provides additional insight that guides diagnosis and ongoing clinical decisions.

Common symptoms and scenarios where testing is recommended:

• Persistent dry cough
• Shortness of breath or chest discomfort
• Fatigue and unexplained tiredness
• Swollen lymph nodes
• Unexplained skin lesions or rashes
• Eye irritation, redness or vision changes
• Generalised inflammatory symptoms
• Monitoring previously diagnosed sarcoidosis

Benefits of the Angiotensin Converting Enzyme Test

• Supports the assessment of sarcoidosis activity
  ACE is one of the few blood markers that can reflect granuloma activity. When used alongside imaging and clinical findings, it helps clinicians understand whether sarcoidosis is likely to be active or relatively quiet.
• Helps monitor response to treatment over time
  Once a diagnosis such as sarcoidosis is made, repeat ACE testing can show whether inflammation is responding to steroids or other therapies. Falling ACE levels may suggest improvement, while rising levels may prompt a reassessment of the treatment plan.
• Adds clarity when symptoms are non-specific
  Fatigue, cough, breathlessness and skin changes can have many causes. An ACE test provides an extra data point that helps separate inflammatory or granulomatous causes from other explanations, improving the quality of the diagnostic work-up.
• Assists in evaluating multi-organ involvement
  Conditions like sarcoidosis can affect lungs, lymph nodes, skin, eyes and other organs at the same time. ACE testing contributes to a more complete picture of systemic disease activity, especially when several organ systems are involved.
• Useful in follow-up after initial diagnosis
  For patients already diagnosed with sarcoidosis or similar conditions, ACE can be used as a longitudinal marker. Tracking trends helps clinicians decide when to step down, maintain or intensify therapy.
• Non-invasive, quick and easily repeatable
  It is a standard venous blood test, so it can be added to other blood panels without additional burden. This makes regular reassessment straightforward during long-term follow-up.
• Can help identify when further investigations are needed
  Persistently high ACE levels may prompt earlier imaging, pulmonary function tests or specialist referral, potentially catching complications sooner and improving long-term outcomes.
• Complements imaging and clinical examination
  ACE is rarely used in isolation; its real strength is as part of a multi-modal assessment. When combined with CT scans, chest X-rays or PET imaging, it helps refine risk assessment and management decisions.

Step-by-Step: How Testing Works

Step 1 – Choose how you want to be tested

You can either visit one of our partner clinics across the UK or book a mobile phlebotomy service to come to you. Both options use the same accredited laboratory and the same quality controls for your sample.

Option 1 – In-clinic blood draw

1. Select your nearest UK clinic and book an appointment online.
2. Attend at the scheduled time; a doctor or trained phlebotomist will take a small blood sample from a vein in your arm.
3. Your sample is securely labelled and transported to the laboratory for ACE analysis.
4. Once processed, your results are uploaded to your secure online account, and you are notified by email or SMS.

Option 2 – Home or hotel phlebotomy (+£60)

1. Choose the home or hotel visit option and select a date and time that suits you.
2. A qualified mobile phlebotomist visits your home, office or hotel anywhere in the UK, bringing all required equipment.
3. Your blood sample is collected on-site, packaged according to strict transport standards and sent directly to the laboratory.
4. You receive your results digitally, without needing to travel or sit in a waiting room.

Step 3 – Review your results

When your ACE result is ready, you can log in, download the report and, if needed, share it with your GP, respiratory specialist or other clinician. Results should always be interpreted in the context of your symptoms and medical history.