Accuracy of Xpert MTB/RIF Ultra for the diagnosis of tuberculosis in adult patients: a retrospective cohort study. (September 2022)

• Record Type: Journal Article
• Authors: Kaswala, Chintan; Schmiedel, Yvonne; Kundu, Debasree; George, Mithun Mohan; Dayanand, Divya; Devasagayam, Emily; S, Abi Manesh; Kumar, Selwyn Selva; Michael, Joy S; Ninan, Marilyn M; Chacko, Geeta; Zachariah, Anand; Sathyendra, Sowmya; Hansdak, Samuel George; Iyadurai, Ramya; Christopher, Devasahayam Jesudas; Gupta, Richa; Karthik, Rajiv; Abraham, Ooriapadickal Cherian; Varghese, George M
• Is Part Of: International journal of infectious diseases. Volume 122(2022)
• Page Start: 566
• Page End: 568
• Publication Date: 2022-09
• Subjects: Xpert MTB/RIF -- Xpert Ultra -- Culture -- Nucleic acid amplification tests -- Mycobacterium tuberculosis -- Sensitivity; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2022.07.016
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: Xpert Mycobacterium tuberculosis /rifampicin (MTB/RIF) Ultra is more sensitive than Xpert MTB/RIF and cultures. Xpert MTB/RIF and cultures have 100% specificity; Xpert MTB/RIF Ultra is 98.1% specific. Xpert Ultra is most sensitive (92%) and specific (100%) on pus samples. Abstract: Objectives: The value of the "trace" result in Xpert Ultra for diagnosing active tuberculosis (TB) remains unclear. Our study evaluated the diagnostic accuracy of Xpert MTB/RIF Ultra (Xpert Ultra) (Cepheid, Sunnyvale, USA) over Xpert MTB/RIF (Xpert) (Cepheid, Sunnyvale, USA) and mycobacterial culture when compared with a composite reference standard (CRS). Methods: A retrospective single-center observational study was conducted in a tertiary care hospital in South India. Over three months, patients (aged ≥15 years) data on Xpert Ultra tests and mycobacterial culture of pulmonary and extrapulmonary samples were extracted from their electronic medical records. Patients were defined as TB cases based on the CRS criteria. Sensitivity, specificity, positive and negative predictive values of diagnostic tests were calculated by comparing them to the CRS. Results: Xpert Ultra was more sensitive (87.8%) than Xpert (72.1%) and culture (44.1%). The specificity of Xpert Ultra was lower (98.1%) than those of Xpert (100%) and culture (100%). The sensitivity (92%) and specificity (100%) of Xpert Ultra were highest when performed on pus samples. Conclusions: Xpert Ultra with the trace category is superior to the conventional Xpert, and mycobacterial culture in identifying TB.