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. 2016 Apr 15;71(5):e119-26.
doi: 10.1097/QAI.0000000000000907.

Implementation and Operational Research: What Happens After a Negative Test for Tuberculosis? Evaluating Adherence to TB Diagnostic Algorithms in South African Primary Health Clinics

K M McCarthy  1 , A D Grant, V Chihota, S Ginindza, L Mvusi, G J Churchyard, K L Fielding
Affiliations

Implementation and Operational Research: What Happens After a Negative Test for Tuberculosis? Evaluating Adherence to TB Diagnostic Algorithms in South African Primary Health Clinics

K M McCarthy et al. J Acquir Immune Defic Syndr. .

Abstract

Introduction and background: Diagnostic tests for tuberculosis (TB) using sputum have suboptimal sensitivity among HIV-positive persons. We assessed health care worker adherence to TB diagnostic algorithms after negative sputum test results.

Methods: The XTEND (Xpert for TB-Evaluating a New Diagnostic) trial compared outcomes among people tested for TB in primary care clinics using Xpert MTB/RIF vs. smear microscopy as the initial test. We analyzed data from XTEND participants who were HIV positive or HIV status unknown, whose initial sputum Xpert MTB/RIF or microscopy result was negative. If chest radiography, sputum culture, or hospital referral took place, the algorithm for TB diagnosis was considered followed. Analysis of intervention (Xpert MTB/RIF) effect on algorithm adherence used methods for cluster-randomized trials with small number of clusters.

Results: Among 4037 XTEND participants with initial negative test results, 2155 (53%) reported being or testing HIV positive and 540 (14%) had unknown HIV status. Among 2155 HIV-positive participants [684 (32%) male, mean age 37 years (range, 18-79 years)], there was evidence of algorithm adherence among 515 (24%). Adherence was less likely among persons tested initially with Xpert MTB/RIF vs. smear [14% (142/1031) vs. 32% (364/1122), adjusted risk ratio 0.34 (95% CI: 0.17 to 0.65)] and for participants with unknown vs. positive HIV status [59/540 (11%) vs. 507/2155 (24%)].

Conclusions: We observed poorer adherence to TB diagnostic algorithms among HIV-positive persons tested initially with Xpert MTB/RIF vs. microscopy. Poor adherence to TB diagnostic algorithms and incomplete coverage of HIV testing represents a missed opportunity to diagnose TB and HIV, and may contribute to TB mortality.

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Conflict of interest statement

The authors have no funding or conflicts of interest to disclose

Figures

FIGURE 1
FIGURE 1
A, The algorithm for the diagnosis of tuberculosis used by health care workers in facilities where GeneXpert testing is available (used throughout the roll-out for Xpert MTB/RIF, from 2011 to 2014, but only published in the “South African National Guidelines for TB diagnosis and management” in 2014). B, The algorithm for the diagnosis of tuberculosis used by health care workers in facilities where GeneXpert testing is not available (South African National Guidelines for TB diagnosis and management, 2009).
See this image and copyright information in PMC

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