T-SPOT.TB Performance in Routine Pediatric Practice in a Low TB Burden Setting

Area of Science:

• Pediatric infectious diseases
• Immunological assays
• Tuberculosis diagnostics

Background:

• Interferon-gamma release assays (IGRAs) like T-SPOT.TB are indirect tests for Mycobacterium tuberculosis infection.
• Evidence for IGRA use in young and HIV-infected children is limited.
• This study evaluated the T-SPOT.TB test's performance in a routine pediatric setting with low tuberculosis burden.

Purpose of the Study:

• To determine the prevalence of invalid, borderline, positive, and negative T-SPOT.TB results in children.
• To investigate associations between test outcomes and demographic variables.
• To assess the utility of T-SPOT.TB testing in routine pediatric use.

Main Methods:

• Analysis of pediatric samples (2010-2015) at Oxford Diagnostic Laboratories.
• Bivariate analysis and logistic regression to estimate associations between test outcomes and demographics.
• Evaluation of over 44,000 samples, including those from children under 5 and samples from various clinic types.

Main Results:

• T-SPOT.TB positivity strongly correlated with state tuberculosis incidence (r=0.60).
• Positive results were more frequent in older children, public health clinics, and rural locations.
• Invalid results (0.6%) were more common in samples from younger children and HIV clinics.

Conclusions:

• The T-SPOT.TB test demonstrated strong correlation with tuberculosis risk factors and yielded evaluable results in 98% of pediatric cases.
• Consideration of local epidemiology and individual patient risk is crucial for incorporating IGRAs into pediatric guidelines.
• The findings support the use of T-SPOT.TB in children, with awareness of specific demographic factors influencing test results.