1 research outputs found
Challenges of tuberculosis prevention through early detection of latent tuberculosis infection in new immigrants to the State of Kuwait
Introduction: Despite management advances worldwide, tuberculosis still remains a
serious uncontrolled disease. The absence of either a ‘gold’ standard diagnostic test,
or a conventional rapid ‘reference’ laboratory test for asymptomatic Mycobacterium
tuberculosis (MTB) carriers complicates disease control. Through mandatory
screening of high-risk groups, early diagnosis of latent tuberculosis infection (LTBI)
cases allows recognition and better control of the tuberculosis pandemic.
Materials and Methods: The current tuberculosis screening guidelines as
recommended by the World Health Organization, chest X-ray and tuberculin skin
test were assessed and revealed rises in TB morbidity and fatality trends in the
Kuwait population (low incidence country). In order to evaluate options for LTBI
diagnosis, the current work implemented a 4-month prospective, observational,
repeated-measure and randomly implemented survey on 180 new immigrants to
Kuwait using a structured risk factor questionnaire whilst, simultaneously evaluating
the performance of the two standard diagnostics (chest X-ray and tuberculin skin
test) with the new biomarker interferon gamma release assays (T-SPOT .TB test and
QuantiFERON Gold In-Tube test (QNF-GIT)); which detect the release of interferon
gamma (INF-γ) released from sensitization to specific MTB antigens.
Results: Associations between various epidemiological risk factors - such as socio-demographic
status, smoking and environmental exposure-contact - were associated
in the laboratory diagnosed LTBI participants. Positive identification of LTBI
prevalence detected by two radiologists was 10.1% having ‘moderate’ inter-reader
agreement (Kappa = 0.505), compared to no positives being detected by three
pulmonologists. TST results were negative (less than 10-mm ‘cut-off’) even in the
86.1% Bacillus Calmette-Guérin vaccinated expatriates. Estimated LTBI using QNFGIT
was 28.3% compared to 41.1% positive T-SPOT .TB test. Both interferon
gamma assays revealed concordant ‘abnormal’ results in 26.1% with ‘good’
agreement (kappa = 0.627).
Conclusion: Detection of latent tuberculosis infection can be facilitated by
introducing evidence-based diagnostic classification depending on history taking of
epidemiological-related risk factors and chest X-ray plus either interferon gamma
assays