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. 2018 May 9;13(5):e0196723.
doi: 10.1371/journal.pone.0196723. eCollection 2018.

MPT64 antigen detection test improves routine diagnosis of extrapulmonary tuberculosis in a low-resource setting: A study from the tertiary care hospital in Zanzibar

Melissa Davidsen Jørstad  1   2 , Msafiri Marijani  3 , Anne Ma Dyrhol-Riise  4   5   6 , Lisbet Sviland  7   8 , Tehmina Mustafa  1   2
Affiliations

MPT64 antigen detection test improves routine diagnosis of extrapulmonary tuberculosis in a low-resource setting: A study from the tertiary care hospital in Zanzibar

Melissa Davidsen Jørstad et al. PLoS One. .

Abstract

Background: Extrapulmonary tuberculosis (EPTB) is a diagnostic challenge. An immunochemistry-based MPT64 antigen detection test (MPT64 test) has reported higher sensitivity in the diagnosis of EPTB compared with conventional methods. The objective of this study was to implement and evaluate the MPT64 test in routine diagnostics in a low-resource setting.

Methods: Patients with presumptive EPTB were prospectively enrolled at Mnazi Mmoja Hospital, Zanzibar, and followed to the end of treatment. Specimens collected were subjected to routine diagnostics, GeneXpert® MTB/RIF assay and the MPT64 test. The performance of the MPT64 test was assessed using a composite reference standard, defining the patients as tuberculosis (TB) cases or non-TB cases.

Results: Patients (n = 132) were classified as confirmed TB (n = 12), probable TB (n = 34), possible TB (n = 18), non-TB (n = 62) and uncategorized (n = 6) cases. Overall, in comparison to the composite reference standard for diagnosis, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the MPT64 test was 69%, 95%, 94%, 75% and 82%, respectively. The MPT64 test performance was best in TB lymphadenitis cases (n = 67, sensitivity 79%, specificity 97%) and in paediatric TB (n = 41, sensitivity 100%, specificity 96%).

Conclusions: We show that the MPT64 test can be implemented in routine diagnostics in a low-resource setting and improves the diagnosis of EPTB, especially in TB lymphadenitis and in children.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Flow-chart showing the study design and patient flow in the study.
NOTE. EPTB, extrapulmonary tuberculosis; TB, tuberculosis; CT, computed tomography; FNAC, fine-needle aspiration cytology. a Not included in the composite reference standard.
Fig 2
Fig 2. Patterns of immunostaining with anti-MPT64 antibody in various specimens.
The signals are seen as granular, reddish staining. A, fine-needle aspirates from lymph nodes, signals were extracellular probably due to cell lysis (A1), mostly intracytoplasmic (A2-A3), and in necrotic areas (A4); B, pleural effusion, intracytoplasmic staining; C1-C2, pus/abscess, intracytoplasmic staining; C3-C4, pericardial effusion, intracytoplasmic staining, and non-specific staining mainly of red blood cells; D1-D2, ascites, intracytoplasmic staining (D1), extracellular probably due to cell lysis (D2); D3-D4, cerebrospinal fluid, extracellular probably due to cell lysis.
See this image and copyright information in PMC

References

    1. Chakravorty S, Sen MK, Tyagi JS. Diagnosis of extrapulmonary tuberculosis by smear, culture, and PCR using universal sample processing technology. J Clin Microbiol. 2005;43(9):4357–62. doi: 10.1128/JCM.43.9.4357-4362.2005 ; PubMed Central PMCID: PMCPMC1234147. - DOI - PMC - PubMed
    1. Malbruny B, Le Marrec G, Courageux K, Leclercq R, Cattoir V. Rapid and efficient detection of Mycobacterium tuberculosis in respiratory and non-respiratory samples. Int J Tuberc Lung Dis. 2011;15(4):553–5. doi: 10.5588/ijtld.10.0497 . - DOI - PubMed
    1. Hillemann D, Rusch-Gerdes S, Boehme C, Richter E. Rapid molecular detection of extrapulmonary tuberculosis by the automated GeneXpert MTB/RIF system. J Clin Microbiol. 2011;49(4):1202–5. doi: 10.1128/JCM.02268-10 ; PubMed Central PMCID: PMCPMC3122824. - DOI - PMC - PubMed
    1. Purohit MR, Mustafa T, Wiker HG, Morkve O, Sviland L. Immunohistochemical diagnosis of abdominal and lymph node tuberculosis by detecting Mycobacterium tuberculosis complex specific antigen MPT64. Diagn Pathol. 2007;2:36 doi: 10.1186/1746-1596-2-36 ; PubMed Central PMCID: PMCPMC2203973. - DOI - PMC - PubMed
    1. Purohit MR, Mustafa T, Wiker HG, Sviland L. Rapid diagnosis of tuberculosis in aspirate, effusions, and cerebrospinal fluid by immunocytochemical detection of Mycobacterium tuberculosis complex specific antigen MPT64. Diagn Cytopathol. 2012;40(9):782–91. doi: 10.1002/dc.21637 . - DOI - PubMed

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