ANGIOTENSIN CONVERTING ENZYME FOR THE DIAGNOSIS OF CHILDHOOD SARCOIDOSIS

Background/Aims Childhood sarcoidosis is a rare multisystem inflammatory granulomatous disease. The prevalence of sarcoidosis in children is unknown due to its rarity. A review of sarcoidosis in Denmark found an incidence in children < 15 years of 0.22-0.27 per 100 000/year. Diagnosis can be challenging given the varied presentations due to multisystem involvement. There is no one laboratory test that is diagnostic for sarcoidosis. Angiotensin converting enzyme (ACE) has been shown to be elevated in 50% of late-onset childhood sarcoidosis. Reference levels are laboratory and age dependent, and healthy children can have levels that are 40-50% higher than in adults. Our aim was to gain a better understanding of the use of ACE in clinical practice and to review its role in diagnosis and management of sarcoidosis. Methods We collated the list of all patients under 18 years who had ACE levels done at our hospital between 1/12/2021 and 30/11/2022 via clinical pathology. Electronic patient records were reviewed for all patients to gather information on demographics, and clinical symptoms. Results We had a total of 98 ACE blood tests done for 58 patients. Clinical notes and results were available for 34 of these patients with a total of 48 ACE results. Age range of patients was 3-17 years with a mean age of 12 years. 19 (56%) patients were female, 15 (44%) were male. 50% were of white ethnicity, 12% of black ethnicity, 3% Indian ethnicity, 3% Pakistani ethnicity, 3% Chinese ethnicity and 29% ethnicity not recorded. 45 were requested by in hospital specialties, 2 from other hospitals and 1 from a GP. Of those requested in hospital 73% had been requested by ophthalmology, rheumatology or dermatology, with the remainder requested by a range of other paediatric specialties. Results ranged from 11-195U/L, with a median of 76U/L. Hospital reference range is 13-64U/L and 18 patients had results >64U/L. Reference ranges for paediatric patients in literature is 29-112U/L. 6 patients had a result>112U/L. One patient had a diagnosis of sarcoidosis. Following the initial results a further 4 years of results were analysed from 02/01/2018-30/11/2022. 10 further patients had ACE results >112U/L. Of these, none had sarcoidosis. Conclusion These results support that the diagnosis of sarcoidosis is rare. ACE results need to be interpreted being mindful that normal childhood ACE levels may be higher than the reference ranges given by hospitals, which may be based on adult ranges. There is need for more research in this area to ascertain diagnostic ACE levels and role of ACE in disease monitoring. I plan to lead a trainee multicentre retrospective project looking at the diagnosis of paediatric sarcoidosis, and within this review the role of ACE levels. Disclosure M.C. Mackay: None. S. Deepak: None. K. Warrier: None. S. Rangaraj: None.