What is the significance of Angiotensin-Converting Enzyme (ACE) level in sarcoidosis?

From the Guidelines

Elevated Angiotensin-Converting Enzyme (ACE) levels are associated with more aggressive disease and multiple-organ involvement in sarcoidosis, but ACE levels alone are not diagnostic for the disease. According to the most recent evidence from 1, serum ACE levels have become a useful tool in the diagnosis of sarcoidosis and for evaluating disease activity. The normal range for ACE is generally considered to be 8-53 U/L, though this can vary slightly between laboratories. In sarcoidosis, levels can range from 50-150 U/L or higher, and approximately 60-80% of patients with active sarcoidosis have elevated ACE levels, but normal levels do not rule out the disease. Some key points to consider when interpreting ACE levels in sarcoidosis include:

• ACE levels can be used to monitor disease activity and response to treatment, with decreasing levels often indicating improvement
• ACE levels should always be interpreted in conjunction with clinical symptoms, imaging studies, and other laboratory tests
• ACE levels can also be elevated in other conditions such as tuberculosis, hyperthyroidism, and certain liver diseases, which is why ACE testing alone is not sufficient for diagnosing sarcoidosis As noted in 1, elevated ACE level test is one of the clinical features supportive of a diagnosis of sarcoidosis, but it is not the only factor to consider. Additionally, the European Respiratory Journal study 1 highlights the importance of considering the risk of death or organ failure and impairment of quality of life when making treatment decisions for sarcoidosis patients. Overall, while ACE levels can be a useful tool in the diagnosis and management of sarcoidosis, they should be interpreted in the context of the individual patient's clinical presentation and other diagnostic tests.

From the Research

Significance of Angiotensin-Converting Enzyme (ACE) Level in Sarcoidosis

• The level of Angiotensin-Converting Enzyme (ACE) is significant in the diagnosis and monitoring of sarcoidosis, as elevated serum ACE activity is found in 60-70% of sarcoidosis patients 2.
• Elevated serum ACE activity can be helpful in confirming a diagnosis of active sarcoidosis and judging the therapeutic response 3.
• However, ACE levels are not specific to sarcoidosis and can be elevated in other conditions, such as Gaucher's disease 3 and non-Hodgkin's lymphoma 4.
• The clinical correlation between ACE levels and disease activity in sarcoidosis is disputable, and ACE levels may not accurately reflect disease severity 4.
• Extremely elevated ACE activity can be suggestive of familial hyperactivity of ACE, a benign condition that can be confirmed by genetic testing 2.
• ACE levels can be useful in monitoring disease activity, but a normal value does not rule out sarcoidosis, and a significant number of patients with sarcoidosis may have normal ACE levels 5.
• The specificity and sensitivity of ACE levels for sarcoidosis are relatively low, with a positive predictive value of 12.76% and a negative predictive value of 94.6% 4.
• ACE levels may be more useful in excluding sarcoidosis than in confirming it, due to their high negative predictive value 4.
• The value of ACE levels in current clinical practice is still a topic of interest, and simpler assays have made it more accessible as a diagnostic tool 6.