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The sensitivity of an interferon-γ release assay in microbiologically confirmed pediatric tuberculosis
Kurt Schopfer1, Hans L Rieder, Thomas Bodmer
1Institute of Infectious Diseases, University of Bern, Friedbühlstrasse 51, 3010, Bern, Switzerland, kurt.schopfer@bluewin.ch.
Insights
The sensitivity of interferon-γ release assays (IGRA) for diagnosing pediatric tuberculosis was low in a high-burden setting. This test is not reliable for ruling in tuberculosis cases in children.
Area of Science:
- Pediatric Infectious Diseases
- Immunology
- Mycobacteriology
Background:
- Tuberculosis diagnosis in children is challenging, especially in high-burden countries.
- Microbiologic confirmation is often difficult, necessitating alternative diagnostic methods.
- Interferon-γ release assays (IGRA) are widely used but their sensitivity in pediatric TB needs further evaluation.
Purpose of the Study:
- To determine the sensitivity of a whole blood interferon-γ release assay (IGRA) in children with microbiologically confirmed tuberculosis.
- To assess the utility of IGRA as a diagnostic tool in pediatric TB.
Main Methods:
- A prospective study involving children with a clinical diagnosis of tuberculosis.
- Microbiologic confirmation using acid-fast bacilli smear, rRNA detection, and Mycobacterium tuberculosis culture.
- Performance of whole blood IGRA on patients with microbiologically confirmed TB.
Main Results:
- Out of 405 children with clinical TB, 91 had microbiologically confirmed disease.
- Eighty-one children with confirmed TB underwent IGRA testing.
- The sensitivity of IGRA was 53.1% (95% CI 42.3–63.6%), unaffected by age, sex, or disease manifestation.
Conclusions:
- The sensitivity of IGRA for microbiologically confirmed pediatric tuberculosis is low.
- IGRA is not suitable as a rule-in test for pediatric TB.
- IGRA may assist in ruling in TB in children with diagnostic challenges.
Unlabelled:
This study aimed at determining the sensitivity of a whole blood interferon-γ release assay (IGRA) among children with microbiologically confirmed tuberculosis in a high-burden country. Children with a diagnosis of tuberculosis based on clinical and radiographic assessment were tested with an IGRA in addition to microbiologic examination of appropriate specimens for acid-fast bacilli, mycobacterial rRNA, and observation for growth of Mycobacterium tuberculosis on appropriate culture media. Of the 405 children with a clinical diagnosis of tuberculosis, 91 (22.5 %) had microbiologically confirmed tuberculosis, of whom 81 were tested with an IGRA. A positive result was obtained in 43 (sensitivity 53.1 %, 95 % confidence interval 42.3 to 63.6 %), uninfluenced by age, sex, or disease manifestation.
Conclusions:
The sensitivity of a whole blood interferon-γ release assay in microbiologically confirmed pediatric tuberculosis was low. An IGRA cannot, thus, be used as rule-in test, but it might be useful to rule in tuberculosis among children in whom tuberculosis is notoriously difficult to confirm microbiologically.
