title: Immunochromatographic assays for detection of Mycobacterium tuberculosis: what is the perfect time to test?
abstract: In this study, we aimed to correlate the analytical performance of SD BIOLINE TB Ag MPT64 Rapid Test kit (MPT64 assay) with the mycobacterial growth unit (GU) reported by the BACTEC MGIT 960 (MGIT 960) instrument. A total of 394 culture isolates reported positive by MGIT 960 were processed daily (until 'day 4') with the MPT64 assay until a positive MPT64 result was obtained and their GU values were noted daily before MPT64 testing. Based on this correlation of MPT64 positivity and corresponding GU values, a GU cut-off was determined. In the validation phase, with the experimentally determined GU cut-off value, 99.1% (576/581) of culture isolates were correctly identified as MTB within 2 days from instrument positivity. All results were available using a single-MPT64 assay strip, making the assay cost-effective. Thus, systematic implementation of the MPT64 assay proved to be cost-effective in a high-throughput laboratory without any delay in patient reporting.
authors.affiliation: P. D. Hinduja National Hospital and Medical Research Centre, Microbiology Department, S1 Building, 5th Floor, Veer Savarkar Marg, Mahim, Mumbai 400016, Maharashtra, India.
authors.forename: Viral
authors.initials: V
authors.lastname: Vadwai
authors.forename: Meeta
authors.initials: M
authors.lastname: Sadani
authors.forename: Reshma
authors.initials: R
authors.lastname: Sable
authors.forename: Asavari
authors.initials: A
authors.lastname: Chavan
authors.forename: Kavitha
authors.initials: K
authors.lastname: Balan
authors.forename: Aparna
authors.initials: A
authors.lastname: Naik
authors.forename: Priti
authors.initials: P
authors.lastname: Kambli
authors.forename: Vaishali
authors.initials: V
authors.lastname: Dhane
authors.forename: Maithili
authors.initials: M
authors.lastname: Patankar
authors.forename: Anjali
authors.initials: A
authors.lastname: Shetty
authors.forename: Camilla
authors.initials: C
authors.lastname: Rodrigues
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D002846:Chromatography, Affinity / Q000191:economics / Q000379:methods*; D019411:Clinical Laboratory Techniques / Q000191:economics / Q000379:methods*; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000302:isolation & purification; D013997:Time Factors; D014376:Tuberculosis / Q000175:diagnosis*
chemical_list: D000942:Antigens, Bacterial