An Evaluation of QuantiFERON-TB Gold in-Tube and Immunological Tests for TB Diagnosis in Iraqi Patients | Chapter 08 | Current Trends in Medicine and Medical Research Vol. 1
Introduction:
Mycobacterium is a genus of Gram-positive bacilli that demonstrates the
staining characteristic of acid-fastness. Its most important species,
Mycobacterium tuberculosis, is the most common etiologic agent of tuberculosis.
Tuberculosis causes ill-health among millions of people each year and ranks as
the second leading cause of death from an infectious disease worldwide. Between
2003 and 2012, the TB case detection rate gradually and consistently increased
to reach thousands cases in 2012 particularly pulmonary type. Latent
tuberculosis infection (LTBI), a non-communicable asymptomatic condition,
persists in some, who might develop tuberculosis disease months or years later.
Aims:
Tuberculosis is an infectious disease caused by the bacillus Mycobacterium
tuberculosis and other related species. It typically affects the lungs
(pulmonary TB) but can affect other sites (extra-pulmonary TB). A profusion of
articles have been published on the accuracy and uses of interferon-gamma
releasing assays for detection of this disease.
Experimental
Design: A prospective study.
Place
and Duration of Study: This study was done in Kirkuk city between November 2012
to February 2013.
Methodology:
The present study included 50 individuals (40 suspected tuberculosis patients
and 10 healthy controls). The patient were examined for the presence of TB by
using QuantiFERON-TB Gold In-Tube(QFT-GIT) assay, polymerase chain reaction
(PCR) and compared them with certain new and routine tests like AFB smear,
OnSite TB rapid test, erythrocyte sedimentation rate and chest X-ray.
Results:
The present study showed a relation between QFT-GIT and OnSite TB rapid test,
and they were positive in 25(86%) at the same time; QFT-GIT positive and OnSite
TB rapid test were negative in 4(14%) of patients; QFT-GIT negative and OnSite
TB rapid test positive were seen in 5(45%); while QFT-GIT and OnSite TB rapid
test were negative in 6(55%) of patients. In the control group only one QFT-GIT
positive but it was OnSite TB test negative. 9(100%) of individuals for both
tests were negative, 29 were males and 21 were females.
Conclusion:
The study highlighted the sensitivity of IGRAs for diagnosis of active TB in
combination with the rapid IgM/lgG tests for TB.The QFT assay appeared to be a
more specific indicator of latent TB infection than TST. The association with
blood groups and vaccination is also significant. Blood group ABO and rhesus
typing were found to be the most prevalent in pulmonary TB patients with blood
group O +ve. Seroprevalence of Mycobacterium tuberculosis antibodies was
relatively high in IgG antibody. QuantiFERON TB Gold in Tube high sensitivity
and specificity compared to TST, and requires only one visit. In close contacts
which were BCG-vaccinated, the QFT assay appeared to be a more specific
indicator of latent TB infection than TST.
Biography of author(s)
Mohemid M. Al-Jebouri
Department
of Microbiology, College of Medicine, University of Tikrit, Tikrit, Iraq
View Volume: https://doi.org/10.9734/BPI/ctmmr/v1
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