AFISE The Prevalence of Latent Tuberculosis Infection

The Prevalence of Latent Tuberculosis Infection estimated
by QuantiFERON-TB Gold In Tube among BCG vaccinated children
Aim To assess the prevalence of Latent TB Infection (LTBI) using an antigen-specific interferon-gamma assay, QuantiFERON
test (QFT), in children exposed.
Material and method A cross sectional study of prevalence was conducted from Sep 2006 to Jan 2007, in three schools from Constanta, Roma-
nia.
Results:
Distribution by age and gender
250
200
150
Boys
Girls
100
Total
50
0
6-8 yrs
8-10 yrs
10-12 yrs
12-14 yrs
Total
Results:
The distribution of LTBI by age and gender
50
40
30
Girls
Boys
20
Total
10
0
6-8 yrs
8-10 yrs
10-12 yrs
12-14 yrs
Total
Results
174 TST positive reactors (74%)
49 QFT tested (28.1%)
28 QuantiFERON positive reactors
LTBI (57.1%)
Conclusion   The prevalence of LTBI determined by TST is high among exposed children.
  There is a strong discrepancy between positive TST and QFT in BCG vaccinated individuals.
Clinical implications   QuantiFERON is more sensitive than TST, being able to identify the natural TB infection from a false positive TST reac-
tion induced by the post BCG vaccine’s allergy.
  It has greater specificity in revealing TB infection in BCG-vaccinated individuals.
Authors:
Oana Cristina Arghir¹,², Maria Ghelberg Talmacel³,
Gheorghita Voicu²
1 School of Medicine, Ovidius University of Constanta, Romania
2 Clinical Pneumology Hospital, Constanta, Romania
3 Health Authority Laboratory Department, Constanta, Romania