RESUMO
INTRODUCTION: Tuberculous lymphadenitis (TBLN) is the most common infectious etiology of peripheral lymphadenopathy in adults, in Turkiye. This study aimed to identify the demographic, clinical, and laboratory variables that differentiate TBLN from non-tuberculous lymphadenitis (NTBLN), as well as the etiology of lymphadenopathy in adults. METHODOLOGY: Patients who were over 18 years old and were referred to the infectious disease outpatient clinics with complaints of swollen peripheral lymph nodes, and who underwent lymph node biopsy between 1 January 2010 and 1 March 2021, were included in this multicenter, nested case-control study. RESULTS: A total of 812 patients at 17 tertiary teaching and research hospitals in Turkiye were included in the study. TBLN was the most frequent diagnosis (53.69%). The proportion of patients diagnosed with TBLN was higher among females; and among those who had a higher erythrocyte sedimentation rate, positive purified protein derivative test, and positive interferon-gamma release test result (p < 0.05). However, TBLN was less frequent among patients with generalized lymphadenopathy, bilateral lymphadenopathy, axillary lymphadenopathy, inguinal lymphadenopathy, hepatomegaly, splenomegaly, leukocytosis, and moderately increased C reactive protein levels (p < 0.05). CONCLUSIONS: Identifying the variables that predict TBLN or discriminate TBLN from NTBLN will help clinicians establish optimal clinical strategies for the diagnosis of adult lymphadenopathy.