Lipoarabinomannan enzyme-linked immunosorbent assay for early diagnosis of childhood tuberculous meningitis

SETTING: Tuberculous meningitis (TBM) is a severe complication of tuberculosis (TB) predominantly affecting young children. Early initiation of treatment is important to prevent morbidity and mortality associated with TBM, emphasising the importance of early diagnosis. Among the most promising new methods for diagnosing TB are antigen-detection assays based on the detection of lipoarabinomannan (LAM). OBJECTIVE: To evaluate the diagnostic value of a commercial, antigen-capture enzyme-linked immunosorbent assay (ELISA) test based on the detection of LAM in urine for the early diagnosis of TBM in children. METHOD: A cross-sectional study in which urine samples from paediatric patients with suspected TBM attending the Tygerberg Children's Hospital, Cape Town, South Africa, were tested for LAM. RESULTS: Complete data were available for 50 of 56 patients with suspected TBM. TBM was diagnosed in 21 (42%) patients and excluded in 29 (58%). The LAM ELISA had a sensitivity of 4.8% and a specificity of 93.1%. Serial measurements in the first 2 weeks after treatment initiation did not improve test performance. CONCLUSION: We have shown that urinary LAM detection was of little value for the diagnosis of TBM in a cohort of paediatric patients with suspected TBM.