Optimal parameters for Gene Xpert MTB/RIF and LAM Strip determine Test for Diagnosis of Tuberculosis using urine from HIV patients at Moi Teaching and Referral Hospital, Kenya

Abstract

The application of Gene Xpert MTB/RIF® assay for testing non-sputum clinical samples in Western Kenya has not been reported. We are reporting on use of Zn, CD4 count, Hb, Creatinine, Proteinuria, and Hematuria as optimal parameters for Gene Xpert MTB/RIF and LAM Strip determine Test for diagnosis of tuberculosis. Urine from HIV/TB co-infected adults (n=158) with CD4+ count <200 cells/mm3was analyzed for mycobacteria tuberculosis DNA. Acid fast-staining, culture, clinical symptoms, laboratory and radiological findings were also assessed. Acid fast staining(55%) were TB positive, however, Gene Xpert test revealed 17(11%) of the patients were TB positive with 94% and 6% being MTB detected low and medium, respectively. Rifampicin resistance was not detected in 88% of the TB Gene Xpert positive patients with the remaining (12%) being indeterminate. LAM test revealed that 28% of the patients were TB positive. Radiology revealed that 45% of the patients had infiltrates. Presence of protein or blood in urine was significantly associated with TB positivity based on LAM strip determine test (48% vs 24%; p-value=0.021). The weighted kappa coefficient was 0.48 (95% CI 0.32-0.63; exact p-value <0.0001).The findings of this study show that urine Xpert MTB/RIF® can be used for diagnosis of TB using urine and taking Zn, CD4 count, Proteinuria, and Hematuria as optimal parameters.