Research

Diagnostic accuracy of GeneXpert MTB/RIF in musculoskeletal tuberculosis: High sensitivity in tissue samples of HIV-infected and HIV-uninfected patients

M Held, M Laubscher, L Workman, H J Zar, R Dunn

Abstract


Background. GeneXpert MTB/RIF is useful for the diagnosis of pulmonary TB in adults, but there is limited evidence on its usefulness in extrapulmonary TB.

Objectives. To investigate the diagnostic accuracy of GeneXpert MTB/RIF in HIV-infected and HIV-uninfected patients with suspected musculoskeletal TB.

Methods. A prospective study of patients with suspected musculoskeletal (bone and joint) TB was undertaken. The diagnostic accuracy of GeneXpert MTB/RIF was compared with the reference standards of culture and histopathology.

Results. A total of 206 biopsies from 201 patients (23% HIV-infected) were evaluated. The sensitivity and specificity of GeneXpert MTB/RIF was 92.3% (84/91) and 99.1% (114/115), respectively. GeneXpert MTB/RIF detected 8.8% more cases than culture (84/91 (92.3%) v. 76/91 (83.5%), respectively; p=0.069). GeneXpert MTB/RIF also detected all 4 multidrug-resistant TB cases and an additional 2 rifampicin-resistant cases in culture-negative samples. The sensitivity of GeneXpert MTB/RIF in HIV-infected patients was 96.9% (31/32) v. 89.6% (43/48) in HIV-uninfected patients (p=0.225).

Conclusion. GeneXpert MTB/RIF is an accurate test for the detection of TB in tissue samples of HIV-infected and HIV-uninfected patients with suspected musculoskeletal TB. A positive GeneXpert MTB/RIF result should be regarded as microbiological confirmation of TB.

 


Authors' affiliations

M Held, Orthopaedic Research Unit, Department of Orthopaedic Surgery, Groote Schuur Hospital, University of Cape Town, South Africa

M Laubscher, Orthopaedic Research Unit, Department of Orthopaedic Surgery, Groote Schuur Hospital, University of Cape Town, South Africa

L Workman, Department of Pediatrics and Child Health, Red Cross War Memorial Children’s Hospital, University of Cape Town and MRC Unit on Child and Adolescent Health, University of Cape Town, South Africa

H J Zar, Department of Pediatrics and Child Health, Red Cross War Memorial Children’s Hospital, University of Cape Town and MRC Unit on Child and Adolescent Health, University of Cape Town, South Africa

R Dunn, Orthopaedic Research Unit, Department of Orthopaedic Surgery, Groote Schuur Hospital, University of Cape Town, South Africa

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Keywords

Tuberculosis; GeneXpert; Xpert MTB/RIF; Sensitivity; Extrapulmonary; Osteoarticular; Bone and joint; Musculoskeletal; Pott’s disease

Cite this article

South African Medical Journal 2017;107(10):854-858. DOI:10.7196/SAMJ.2017.v107i10.11186

Article History

Date submitted: 2017-09-22
Date published: 2017-09-22

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