Interpretation of TST and IGRA testing in the evaluation of suspected NTM lymphadenitis in children

Definitive diagnosis of NTM lymphadenitis requires isolation of NTM from culture or polymerase chain reaction testing of fistula drainage, tissue, or caseous material. Pending definitive diagnosis, it is important to try to differentiate NTM from TB because they have different treatment and public health implications. This algorithm provides an overview of the interpretation of TST and IGRA testing in children with suspected NTM lymphadenitis. It is meant to be used with UpToDate content on NTM lymphadenitis and TB in children. Refer to UpToDate content for additional details, including clinical features, alternative diagnoses, laboratory confirmation, and management of NTM lymphadenitis in children, as well as risk factors for TB in children.