Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Aug 14;16(16):2912.
doi: 10.3390/ijerph16162912.

Evaluating Latent Tuberculosis Infection Test Performance Using Latent Class Analysis in a TB and HIV Endemic Setting

Shahieda Adams  1 , Rodney Ehrlich  1 , Roslynn Baatjies  2 , Nandini Dendukuri  3 , Zhuoyu Wang  3 , Keertan Dheda  4   5
Affiliations

Evaluating Latent Tuberculosis Infection Test Performance Using Latent Class Analysis in a TB and HIV Endemic Setting

Shahieda Adams et al. Int J Environ Res Public Health. .

Abstract

Background: Given the lack of a gold standard for latent tuberculosis infection (LTBI) and paucity of performance data from endemic settings, we compared test performance of the tuberculin skin test (TST) and two interferon-gamma-release assays (IGRAs) among health-care workers (HCWs) using latent class analysis. The study was conducted in Cape Town, South Africa, a tuberculosis and human immunodeficiency virus (HIV) endemic setting Methods: 505 HCWs were screened for LTBI using TST, QuantiFERON-gold-in-tube (QFT-GIT) and T-SPOT.TB. A latent class model utilizing prior information on test characteristics was used to estimate test performance.

Results: LTBI prevalence (95% credible interval) was 81% (71-88%). TST (10 mm cut-point) had highest sensitivity (93% (90-96%)) but lowest specificity (57%, (43-71%)). QFT-GIT sensitivity was 80% (74-91%) and specificity 96% (94-98%), and for TSPOT.TB, 74% (67-84%) and 96% (89-99%) respectively. Positive predictive values were high for IGRAs (90%) and TST (99%). All tests displayed low negative predictive values (range 47-66%). A composite rule using both TST and QFT-GIT greatly improved negative predictive value to 90% (range 80-97%).

Conclusion: In an endemic setting a positive TST or IGRA was highly predictive of LTBI, while a combination of TST and IGRA had high rule-out value. These data inform the utility of LTBI-related immunodiagnostic tests in TB and HIV endemic settings.

Keywords: health care worker; latent class analysis; latent tuberculosis infection.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

References

    1. Dheda C., Barry C.E., 3rd, Maartens G. Tuberculosis. Lancet. 2016;387:1211–1226. doi: 10.1016/S0140-6736(15)00151-8. - DOI - PMC - PubMed
    1. World Health Organization . Latent Tuberculosis Infection: Updated and Consolidated Guidelines for Programmatic Management. World Health Organization; Geneva, Switzerland: 2018. License: CC BY-NC-SA 3.0 IGO. - PubMed
    1. Department of Health. South Africa National Tuberculosis Management Guidelines 2014. [(accessed on 24 July 2019)]; Available online: https://www.health-e.org.za/wp-content/uploads/2014/06/NTCP_Adult_TB-Gui....
    1. Shisana O., Hall E., Chavea J., Schwabe C. HIV/AIDS prevalence South African health workers. S. Afr. Med. J. 2004;94:846–850. - PubMed
    1. Kranzer K., Bekker L.G., van Schaik N., Thebus L., Dawson M., Caldwell J., Hausler H., Grant R., Wood R. Community health care workers in South Africa are at increased risk for tuberculosis. S. Afr. Med. J. 2010;100:224. doi: 10.7196/SAMJ.3903. - DOI - PubMed

Publication types