{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T18:44:15Z","timestamp":1781203455496,"version":"3.54.1"},"reference-count":27,"publisher":"BMJ","issue":"9","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2023,8,31]]},"published-print":{"date-parts":[[2023,9]]},"abstract":"<jats:p>In patients with suspected phaeochromocytoma, biochemical screening of urine or blood for excess secretion catecholamines and\/or their metabolites is performed. Elevated levels of catecholamines and metanephrines help in establishing the diagnosis of phaeochromocytoma. In two patients with adrenal lesions who were subjected to biochemical testing significantly elevated urinary normetanephrines appeared to establish the diagnosis of phaeochromocytoma. However, on subsequent investigations, this was demonstrated to be a \u2018false positive\u2019 finding. Both these patients were on sulfasalazine, an anti-inflammatory drug used in inflammatory bowel disease, rheumatoid arthritis and ankylosing spondylitis. Sulfasalazine can cause analytical interference in some assays for urinary normetanephrine and result in spuriously elevated levels, leading to misdiagnosis of phaeochromocytoma. In this report, one patient underwent adrenalectomy and another had conservative management.<\/jats:p>\n               <jats:p>Although this has been previously reported, increased awareness of the possibility of false-positive results on urinary metanephrines testing is important to reduce the potential for misdiagnosis and unnecessary treatment.<\/jats:p>","DOI":"10.1136\/bcr-2022-253597","type":"journal-article","created":{"date-parts":[[2023,9,20]],"date-time":"2023-09-20T13:06:06Z","timestamp":1695215166000},"page":"e253597","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":5,"title":["Sulfasalazine as a cause of false-positive elevation of urinary normetanephrine in patients with adrenal mass and suspected phaeochromocytoma: a diagnostic challenge"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4289-3447","authenticated-orcid":false,"given":"Eunice Ter","family":"Zuling","sequence":"first","affiliation":[{"name":"General Surgery, Northern General Hospital, Sheffield, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miguel","family":"Debono","sequence":"additional","affiliation":[{"name":"Department of Diabetes and Endocrinology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edmund","family":"Rab","sequence":"additional","affiliation":[{"name":"Sheffield Laboratory Medicine, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabapathy","family":"Balasubramanian","sequence":"additional","affiliation":[{"name":"Endocrine Surgery, Northern General Hospital, Sheffield, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2023,9,20]]},"reference":[{"key":"2025082700085597000_16.9.e253597.1","doi-asserted-by":"publisher","DOI":"10.1177\/2042018812437356"},{"key":"2025082700085597000_16.9.e253597.2","doi-asserted-by":"crossref","first-page":"870","DOI":"10.4158\/EP15618.OR","article-title":"Clinical outcomes in adrenal incidentaloma: experience from one center","volume":"21","author":"Patrova","year":"2015","journal-title":"Endocr Pract"},{"key":"2025082700085597000_16.9.e253597.3","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2018-01707"},{"key":"2025082700085597000_16.9.e253597.4","doi-asserted-by":"publisher","DOI":"10.1530\/EC-17-0321"},{"key":"2025082700085597000_16.9.e253597.5","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2014-1498"},{"key":"2025082700085597000_16.9.e253597.6","doi-asserted-by":"publisher","DOI":"10.1001\/jama.287.11.1427"},{"key":"2025082700085597000_16.9.e253597.7","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2002-030005"},{"key":"2025082700085597000_16.9.e253597.8","doi-asserted-by":"publisher","DOI":"10.1530\/EC-17-0071"},{"key":"2025082700085597000_16.9.e253597.9","unstructured":"Pacak K , Tella S . 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