From the Guidelines
Serum angiotensin converting enzyme (ACE) levels are a useful diagnostic marker for sarcoidosis, but should be interpreted with caution due to limited sensitivity and specificity, as evidenced by the 2020 European position paper on rhinosinusitis and nasal polyps 1. When evaluating a patient for sarcoidosis, it is essential to consider the clinical, radiological, and histological evidence of non-caseating granulomas, in addition to serum ACE levels. The usefulness of serum ACE levels in diagnosing sarcoidosis is supported by the fact that elevated levels are usually associated with more aggressive disease and multiple-organ involvement 1. However, it is crucial to note that ACE levels can be normal in some sarcoidosis patients and elevated in other conditions, highlighting the need for a comprehensive evaluation. Some key points to consider when interpreting serum ACE levels in the context of sarcoidosis include:
- Elevated serum ACE levels are associated with more aggressive disease and multiple-organ involvement 1
- Serum ACE levels can be useful for monitoring disease activity and treatment response in established sarcoidosis cases
- The test should be interpreted in the context of clinical presentation, imaging findings, and ideally histopathological confirmation of non-caseating granulomas
- Genetic polymorphisms can affect baseline ACE levels, which may complicate interpretation in some patients 1. Overall, while serum ACE testing is commonly ordered in the workup of suspected sarcoidosis, it should not be used in isolation for diagnosis but rather as part of a comprehensive evaluation, as recommended by the 2020 European position paper on rhinosinusitis and nasal polyps 1.
From the Research
Serum Angiotensin Converting Enzyme and Sarcoidosis
- Serum angiotensin converting enzyme (SACE) has been found to be a useful adjunct to the diagnosis, assessment of disease activity, and management of sarcoidosis 2.
- The sensitivity and specificity of SACE as a diagnostic test in sarcoidosis are influenced by the relative frequency of active and inactive sarcoidosis, as well as the prevalence of other diseases such as military tuberculosis and silicosis 2.
- SACE levels have been found to correlate well with disease activity longitudinally, both in relation to spontaneous remission and steroid therapy, and are thus helpful in patient management 2.
- However, other studies have found that ACE levels are not useful for following disease activity in patients during a change in medication 3, and that high ACE has a poor sensitivity and insufficient specificity for diagnosis of sarcoidosis 4.
- Measurement of SACE is considered the most useful test for diagnosing and monitoring disease activity in sarcoidosis, but elevated levels are not specific for sarcoidosis and can be found in other conditions 5.
Diagnostic Utility of Angiotensin-Converting Enzyme
- The diagnostic utility of angiotensin-converting enzyme (ACE) for diagnosis of sarcoidosis has been investigated in a population-based study, which found that high ACE has a sensitivity of 41.4% and a specificity of 89.9% for diagnosis of sarcoidosis 4.
- The positive predictive value (PPV) and negative predictive value (NPV) of high ACE for diagnosis of sarcoidosis were found to be 25.4% and 94.9%, respectively 4.
- These findings suggest a limited role of ACE in clinical practice for the diagnosis of sarcoidosis 4.
Treatment of Sarcoidosis
- Corticosteroids are the drug of choice for the treatment of sarcoidosis, and are usually effective for all forms of the disease 6.
- However, due to the potential toxicities of corticosteroids, alternative medications often need to be considered, and efforts should be made to minimize the corticosteroid dose while keeping the risk of toxicity as low as possible 6.