A simple protocol for tuberculin skin test reading certification.

Lara De Lima Gloria,Anete Trajman,Mayara Lisboa Bastos,Bráulio Dos Santos Júnior

doi:10.1590/0102-311x00027321

Abstract

Although tuberculosis preventive therapy is one of the cornerstones for eliminating the disease, many barriers exist in the cascade of care for latent tuberculosis infection, including the need to certify healthcare professionals for reading tuberculin skin tests (TST). This paper proposes and evaluates a simple protocol for TST reading training. Primary care workers from different backgrounds received a 2-hour theoretical course, followed by a practical course on bleb reading. Blebs were obtained by injecting saline into sausages and then in volunteers. A certified trainer then evaluated the effectiveness of this protocol by analyzing the trainees' ability to read TST induration in clinical routine, blinded to each other's readings. Interobserver agreement was analyzed using the Bland-Altman test. The trainees' reading accuracy was calculated using two cut-off points - 5 and 10mm - and the effect of the number of readings was analyzed using a linear mixed model. Eleven healthcare workers read 53 saline blebs and 88 TST indurations, with high agreement for TST reading (0.07mm average bias). Sensitivity was 100% (94.6; 100.0) at 5mm cut-off and 87.3% (75.5; 94.7) at 10mm cut-off. The regression model found no effect of the number of readings [coefficient: -0.007 (-0.055; 0.040)]. A simple training protocol for reading TST with saline blebs simulations in sausages and volunteers was sufficient to achieve accurate TST induration readings, with no effect observed for the number of readings. Training with saline blebs injected into voluntary individuals is safer and easier than the traditional method.

Highlights

Tuberculosis (TB) remains the first cause of death from infectious disease worldwide 1
TST is a mandatory test in the latent tuberculosis infection (LTBI) cascade of care, except for patients living with HIV (PLHIV) or for patients younger than five years old, who have a higher risk of progressing to active disease 2
All training steps were provided by an experienced LTBI physician (A.T.) with no TST certification or experience with TST reading, who

Summary

Introduction

Tuberculosis (TB) remains the first cause of death from infectious disease worldwide 1. The risk of progression from LTBI to active disease is higher in those with a positive LTBI test, either the tuberculin skin test (TST) or interferon-gamma release assays (IGRA) 6. TPT has been shown to be more beneficial for those with a positive LTBI test [7,8,9]. TST (or IGRA, where available) is a mandatory test in the LTBI cascade of care, except for patients living with HIV (PLHIV) or for patients younger than five years old, who have a higher risk of progressing to active disease 2. Of the 30 million HIV-negative individuals five years of age or older that should receive TPT by 2022 4, 20 million require a positive LTBI test. Newer and more specific TST using recombinant tuberculin based on ESAT-6 and CP-10 proteins, have already been adopted in some BRICS countries [11,12,13]

Methods

Results

Conclusion