Accuracy of a novel urine test, Fujifilm SILVAMP TB LAM, for the diagnosis of pulmonary tuberculosis in children.

BACKGROUND An accurate point-of-care test for tuberculosis in children remains an elusive goal. Recent evaluation of a novel point-of-care urinary lipoarabinomannan test, Fujifilm SILVAMP TB LAM (FujiLAM) in HIV-infected adults showed significantly superior sensitivity than the current Alere Determine TB LAM test (AlereLAM). We therefore compared the accuracy of FujiLAM and AlereLAM in children with suspected tuberculosis. METHODS Children hospitalized with suspected tuberculosis in Cape Town, South Africa were enrolled (consecutive admissions plus enrichment for a group of HIV-infected children with tuberculosis), urine collected and biobanked, and sputum tested with mycobacterial culture and Xpert MTB/RIF or Xpert MTB/RIF Ultra. Biobanked urine was subsequently batch tested with FujiLAM and AlereLAM. Children were categorised as having microbiologically-confirmed TB, unconfirmed TB (clinically diagnosed) or unlikely TB. RESULTS A total of 204 children were enrolled and had valid results from both index tests as well as sputum microbiological testing. Compared to a microbiological reference standard, the sensitivity of FujiLAM and AlereLAM was similar (42% and 50% respectively), but lower than Xpert MTB/RIF of sputum (74%). Sensitivity of FujiLAM was higher in HIV-infected children (60%) and malnourished children (62%). Specificity of FujiLAM was substantially higher than AlereLAM (92% vs. 66%). Specificity of both tests was higher in children two years or older (FujiLAM 96% and AlereLAM 72%). CONCLUSION The high specificity of FujiLAM suggests utility as a 'rule-in' test for children with a high pretest probability of tuberculosis, including hospitalized children with HIV-infection or malnutrition.