Impact of cartridge-based nucleic acid amplification test (CBNAAT) introduction on the detection of pulmonary and extra-pulmonary tuberculosis in Bhubaneswar, Odisha

Abstract

Background: Compared to conventional microscopy, the cartridge-based nucleic acid amplification test (CBNAAT, Xpert MTB/RIF, Cepheid, USA) has the dual advantage of higher sensitivity to detect Mycobacterium tuberculosis (M. tb), and the ability to detect rifampicin resistance.

Aim: To evaluate the impact of the CBNAAT on the detection of pulmonary and extra-pulmonary tuberculosis from private and public healthcare facilities in Bhubaneswar, Odisha.

Materials and methods: The study included specimens received between June 2015 to February 2017 from public and private health sectors for tuberculosis diagnosis at a national reference laboratory for tuberculosis in Bhubaneswar, where the CBNAAT was initiated in February 2016. We retrospectively collected the patients' socio-demographic characteristics from their test request form, CBNAAT results from the CBNAAT register and PMDT culture and drug susceptibility testing (DST) register and validated the data by comparing the patient details and test results from the CBNAAT software.

Results: From June 2015 to January 2016, 106 samples were received from Bhubaneswar at the reference laboratory, of which there were zero referrals from the private sector and zero referrals of extra-pulmonary tuberculosis (TB) samples. After initiation of the CBNAAT, from February 2016 to February 2017, 1262 specimens were received, of which 55.2% (696/1262), 17.8% (225/1262), 17.2% (217/1262), and 9.8% (124/1262) were from government hospitals and medical colleges, private hospitals, private practitioners, and district TB centers, respectively.

Conclusion: The availability of TB diagnostics at public sector facilities to patients from private sectors and the rollout of the CBNAAT increased the referral of patients from private health facilities and the referral of paucibacillary non-sputum samples.

Keywords: Cartridge-based nucleic acid amplification test; extra-pulmonary tuberculosis; tuberculosis.