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Interferon-gamma release assay as a diagnostic test for tuberculosis-associated uveitis.

Ang M, Wong W, Ngan CC, Chee SP - Eye (Lond) (2012)

Bottom Line: Those with T-SPOT.TB- or TST-positive results were referred to infectious diseases physician for evaluation.Patients with either a T-SPOT.TB (1.44; 95% confidence intervals (CI), 0.86-2.42) or TST (1.47; 95% CI, 1.12-1.94)-positive result are more likely to have TAU.Negative T-SPOT.TB or TST results do not exclude TAU (negative likelihood ratios <1.0).

View Article: PubMed Central - PubMed

Affiliation: Singapore National Eye Centre, National University of Singapore, Singapore, Singapore.

ABSTRACT

Background: To study the use of interferon-gamma release assay (IFN-γ) (IGRAs) as a diagnostic test for tuberculosis (TB)-associated uveitis (TAU).

Design: Prospective cohort study.

Participants: Consecutive new patients (n=162) with clinical ocular signs suggestive of TAU, seen >1 year period at a single tertiary center.

Methods: All subjects underwent investigations to rule out underlying disease, including T-SPOT.TB and tuberculin skin test (TST). Twenty-one subjects with underlying disease and three with interdeterminate T-SPOT.TB results were excluded. Those with T-SPOT.TB- or TST-positive results were referred to infectious diseases physician for evaluation. Anti-TB therapy (ATT) was prescribed if required. Patients' treatment response and recurrence were monitored for six months after completion of ATT, if given; or 1 year if no ATT was given.

Main outcome measure: Diagnosis of TAU.

Results: Mean age of study cohort (n=138) was 46.8 ± 15.3 years. Majority were Chinese (n=80, 58.0%) and female (n=75, 54.3%). TST was more sensitive than T-SPOT.TB (72.0% vs 36.0%); but T-SPOT.TB was more specific (75.0% vs 51.1%) for diagnosing TAU. Patients with either a T-SPOT.TB (1.44; 95% confidence intervals (CI), 0.86-2.42) or TST (1.47; 95% CI, 1.12-1.94)-positive result are more likely to have TAU. The accuracy of diagnosing TAU increases when both tests are used in combination (area under the receiver operator curve=0.665; 95% CI, 0.533-0.795). Patients with both tests positive are 2.16 (95% CI, 1.23-3.80) times more likely to have TAU. Negative T-SPOT.TB or TST results do not exclude TAU (negative likelihood ratios <1.0).

Conclusions: We recommend using a combination of clinical signs, IGRA, and TST to diagnose TAU.

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Related in: MedlinePlus

AUC for tuberculin skin test (T) and T-SPOT.TB (S).
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fig3: AUC for tuberculin skin test (T) and T-SPOT.TB (S).

Mentions: The study cohort was divided into four main groups, as illustrated in Figure 2: S+T+ (both T-SPOT.TB and TST positive), T+ (only TST positive, T-SPOT.TB negative), S+ (only T-SPOT.TB positive, TST negative), and S−T− (neither test positive). The statistical basis of our study involves the comparison of these four groups and their respective final diagnosis of TAU. We estimated the sensitivities, specificities, and AUC of each test individually and when used in combination (Table 2). In the analysis of each test individually, the TST (60.9% 95% CI, 52.7–69.0) has a higher diagnostic accuracy than the T-SPOT.TB (58.7% 95% CI, 50.5–66.9). Although the TST is more sensitive as compared with T-SPOT.TB (72.0% vs 36.0%), the latter is more specific for diagnosis (75.0 vs 51.1%). The incorporated ROC (AUC) value for TST (0.616; 95% CI, 0.534–0.698) was greater than for T-SPOT.TB (0.555; 95% CI, 0.474–0.636) — Figure 3.


Interferon-gamma release assay as a diagnostic test for tuberculosis-associated uveitis.

Ang M, Wong W, Ngan CC, Chee SP - Eye (Lond) (2012)

AUC for tuberculin skin test (T) and T-SPOT.TB (S).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351054&req=5

fig3: AUC for tuberculin skin test (T) and T-SPOT.TB (S).
Mentions: The study cohort was divided into four main groups, as illustrated in Figure 2: S+T+ (both T-SPOT.TB and TST positive), T+ (only TST positive, T-SPOT.TB negative), S+ (only T-SPOT.TB positive, TST negative), and S−T− (neither test positive). The statistical basis of our study involves the comparison of these four groups and their respective final diagnosis of TAU. We estimated the sensitivities, specificities, and AUC of each test individually and when used in combination (Table 2). In the analysis of each test individually, the TST (60.9% 95% CI, 52.7–69.0) has a higher diagnostic accuracy than the T-SPOT.TB (58.7% 95% CI, 50.5–66.9). Although the TST is more sensitive as compared with T-SPOT.TB (72.0% vs 36.0%), the latter is more specific for diagnosis (75.0 vs 51.1%). The incorporated ROC (AUC) value for TST (0.616; 95% CI, 0.534–0.698) was greater than for T-SPOT.TB (0.555; 95% CI, 0.474–0.636) — Figure 3.

Bottom Line: Those with T-SPOT.TB- or TST-positive results were referred to infectious diseases physician for evaluation.Patients with either a T-SPOT.TB (1.44; 95% confidence intervals (CI), 0.86-2.42) or TST (1.47; 95% CI, 1.12-1.94)-positive result are more likely to have TAU.Negative T-SPOT.TB or TST results do not exclude TAU (negative likelihood ratios <1.0).

View Article: PubMed Central - PubMed

Affiliation: Singapore National Eye Centre, National University of Singapore, Singapore, Singapore.

ABSTRACT

Background: To study the use of interferon-gamma release assay (IFN-γ) (IGRAs) as a diagnostic test for tuberculosis (TB)-associated uveitis (TAU).

Design: Prospective cohort study.

Participants: Consecutive new patients (n=162) with clinical ocular signs suggestive of TAU, seen >1 year period at a single tertiary center.

Methods: All subjects underwent investigations to rule out underlying disease, including T-SPOT.TB and tuberculin skin test (TST). Twenty-one subjects with underlying disease and three with interdeterminate T-SPOT.TB results were excluded. Those with T-SPOT.TB- or TST-positive results were referred to infectious diseases physician for evaluation. Anti-TB therapy (ATT) was prescribed if required. Patients' treatment response and recurrence were monitored for six months after completion of ATT, if given; or 1 year if no ATT was given.

Main outcome measure: Diagnosis of TAU.

Results: Mean age of study cohort (n=138) was 46.8 ± 15.3 years. Majority were Chinese (n=80, 58.0%) and female (n=75, 54.3%). TST was more sensitive than T-SPOT.TB (72.0% vs 36.0%); but T-SPOT.TB was more specific (75.0% vs 51.1%) for diagnosing TAU. Patients with either a T-SPOT.TB (1.44; 95% confidence intervals (CI), 0.86-2.42) or TST (1.47; 95% CI, 1.12-1.94)-positive result are more likely to have TAU. The accuracy of diagnosing TAU increases when both tests are used in combination (area under the receiver operator curve=0.665; 95% CI, 0.533-0.795). Patients with both tests positive are 2.16 (95% CI, 1.23-3.80) times more likely to have TAU. Negative T-SPOT.TB or TST results do not exclude TAU (negative likelihood ratios <1.0).

Conclusions: We recommend using a combination of clinical signs, IGRA, and TST to diagnose TAU.

Show MeSH
Related in: MedlinePlus