12 research outputs found
Mycobacterium tuberculosis Infection in Young Children: Analyzing the Performance of the Diagnostic Tests
This study evaluated the performance of the Tuberculin Skin Test (TST) and Quantiferon-TB Gold in-Tube (QFT) and the possible association of factors which may modify their results in young children (0-6 years) with recent contact with an index tuberculosis case. Materials and Methods: A cross-sectional study including 135 children was conducted in Manaus, Amazonas-Brazil. The TST and QFT were performed and the tests results were analyzed in relation to the personal characteristics of the children studied and their relationship with the index case. Results: The rates of positivity were 34.8% (TST) and 26.7% (QFT), with 14.1% of indeterminations by the QFT. Concordance between tests was fair (Kappa = 0.35 P<0.001). Both the TST and QFT were associated with the intensity of exposure (Linear OR = 1.286, P = 0.005; Linear OR = 1.161, P = 0.035 respectively) with only the TST being associated with the time of exposure (Linear OR = 1.149, P = 0.009). The presence of intestinal helminths in the TST+ group was associated with negative QFT results (OR = 0.064, P = 0.049). In the TST- group lower levels of ferritin were associated with QFT+ results (Linear OR = 0.956, P = 0.036). Conclusions: Concordance between the TST and QFT was lower than expected. The factors associated with the discordant results were intestinal helminths, ferritin levels and exposure time to the index tuberculosis case. In TST+ group, helminths were associated with negative QFT results suggesting impaired cell-mediated immunity. The TST-&QFT+ group had a shorter exposure time and lower ferritin levels, suggesting that QFT is faster and ferritin may be a potential biomarker of early stages of tuberculosis infection
Mycobacterium tuberculosis infection in young children: analyzing the performance of the diagnostic tests.
OBJECTIVE:This study evaluated the performance of the Tuberculin Skin Test (TST) and Quantiferon-TB Gold in-Tube (QFT) and the possible association of factors which may modify their results in young children (0-6 years) with recent contact with an index tuberculosis case. MATERIALS AND METHODS:A cross-sectional study including 135 children was conducted in Manaus, Amazonas-Brazil. The TST and QFT were performed and the tests results were analyzed in relation to the personal characteristics of the children studied and their relationship with the index case. RESULTS:The rates of positivity were 34.8% (TST) and 26.7% (QFT), with 14.1% of indeterminations by the QFT. Concordance between tests was fair (Kappaâ=â0.35 P<0.001). Both the TST and QFT were associated with the intensity of exposure (Linear ORâ=â1.286, Pâ=â0.005; Linear ORâ=â1.161, Pâ=â0.035 respectively) with only the TST being associated with the time of exposure (Linear ORâ=â1.149, Pâ=â0.009). The presence of intestinal helminths in the TST+ group was associated with negative QFT results (ORâ=â0.064, Pâ=â0.049). In the TST- group lower levels of ferritin were associated with QFT+ results (Linear ORâ=â0.956, Pâ=â0.036). CONCLUSIONS:Concordance between the TST and QFT was lower than expected. The factors associated with the discordant results were intestinal helminths, ferritin levels and exposure time to the index tuberculosis case. In TST+ group, helminths were associated with negative QFT results suggesting impaired cell-mediated immunity. The TST-&QFT+ group had a shorter exposure time and lower ferritin levels, suggesting that QFT is faster and ferritin may be a potential biomarker of early stages of tuberculosis infection
Mycobacterium tuberculosis Infection in Young Children: Analyzing the Performance of the Diagnostic Tests
This study evaluated the performance of the Tuberculin Skin Test (TST) and Quantiferon-TB Gold in-Tube (QFT) and the possible association of factors which may modify their results in young children (0-6 years) with recent contact with an index tuberculosis case. Materials and Methods: A cross-sectional study including 135 children was conducted in Manaus, Amazonas-Brazil. The TST and QFT were performed and the tests results were analyzed in relation to the personal characteristics of the children studied and their relationship with the index case. Results: The rates of positivity were 34.8% (TST) and 26.7% (QFT), with 14.1% of indeterminations by the QFT. Concordance between tests was fair (Kappa = 0.35 P<0.001). Both the TST and QFT were associated with the intensity of exposure (Linear OR = 1.286, P = 0.005; Linear OR = 1.161, P = 0.035 respectively) with only the TST being associated with the time of exposure (Linear OR = 1.149, P = 0.009). The presence of intestinal helminths in the TST+ group was associated with negative QFT results (OR = 0.064, P = 0.049). In the TST- group lower levels of ferritin were associated with QFT+ results (Linear OR = 0.956, P = 0.036). Conclusions: Concordance between the TST and QFT was lower than expected. The factors associated with the discordant results were intestinal helminths, ferritin levels and exposure time to the index tuberculosis case. In TST+ group, helminths were associated with negative QFT results suggesting impaired cell-mediated immunity. The TST-&QFT+ group had a shorter exposure time and lower ferritin levels, suggesting that QFT is faster and ferritin may be a potential biomarker of early stages of tuberculosis infection
Odds ratio and confidence interal of 95% for the Tuberculosis Skin Test positive results according to time of exposure (months) to index case.
<p>Odds ratio and confidence interal of 95% for the Tuberculosis Skin Test positive results according to time of exposure (months) to index case.</p
Baseline demographic and clinical data of the study participants.
<p>TST: Tuberculin Skin Test, QFT: QuantiFERON-TB Gold In-Tube, MTC-score: <i>Mycobacterium tuberculosis</i> contact score, BCG: Bacillus Calmette-GuĂ©rin.</p>#<p>Categorical variables expressed as number of subjects (n) and percentage (%) compared to those evaluated with the characteristic studied. Quantitative variables expressed as mean and interquartile range (IQR).</p>a<p>In the 12 weeks prior to the study.</p>b<p>Risk of malnutrition was defined as a Z score for weight less than â1 SDs for age and gender; malnutrition was defined â2 SDs for age and gender.</p
Multivariate logistic regression according to factors for positive QFT results stratified by TST results.
<p>TST: Tuberculin Skin Test, QFT: QuantiFERON-TB Gold In-Tube, MTC-score: <i>Mycobacterium tuberculosis</i> contact score, BCG: Bacillus Calmette-Guérin.</p>a<p>logistic regression coefficient related to quantitative variable.</p>b<p>Linear odds ratio; exponential to the regression coefficient.</p
Bivariate analysis and Multivariate logistic regression for TST results and QFT results.
<p>TST: Tuberculin Skin Test, QFT: QuantiFERON-TB Gold In-Tube, MTC-score: <i>Mycobacterium tuberculosis</i> contact score, BCG: Bacillus Calmette-Guérin.</p>#<p>Categorical variables expressed as percentage (%) and quantitative variables expressed as mean and interquartile range (IQR).</p>a<p>In the 12 weeks prior to the study.</p>b<p>Linear odds ratio.</p
Odds ratio and confidence interval of 95% for the Tuberculin Skin Test âTSTâ (blue) and QuantiFERON-TB Gold in-Tube âQFTâ (red) positive results according to the intensity of exposure to index case by <i>Mycobacterium tuberculosis</i> contact score (MTC-score).
<p>The MTC-score is from 0 to 15 and is based on the assumption that the gradient of <i>Mtb</i> exposure is a composite function of the infectivity of the index case (0â4), the duration of exposure -hours per day- (0â4), the relationship to index case (0â4) and the type of exposure (0â3).</p
Comparison of the TST and QFT results.
<p>TST: Tuberculin Skin Test, QFT: QuantiFERON-TB Gold In-Tube, n: number of subjects.</p
Flow diagram of enrolment (QFT: QuantiFERON-TB Gold In-Tube).
<p>Flow diagram of enrolment (QFT: QuantiFERON-TB Gold In-Tube).</p