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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

Flowchart depicting study cohort and follow-up. n, number of study subjects; ATT, anti-tubercular treatment.
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fig1: Flowchart depicting study cohort and follow-up. n, number of study subjects; ATT, anti-tubercular treatment.

Mentions: Briefly, all study subjects underwent a full systemic review, ocular examination, and standard baseline investigations — Figure 1. Blood was taken for T-SPOT.TB before TST was performed. Patients were excluded if they had (1) any other possible infectious or non-infectious cause to account for the uveitis or (2) a T-SPOT.TB result that was indeterminate as these tests cannot be interpreted. All patients were referred to the infectious diseases physician at Singapore General Hospital for review and were prescribed Anti-TB therapy (ATT) if required. Patients were followed up every 2 weeks for 8 weeks, then 2–3 monthly (or more frequently as required) to monitor response to therapy. Systemic corticosteroids were added if there was any increase in ocular inflammation after commencing ATT,15 defined as a two-step increase in inflammation using the Standardization of Uveitis Nomenclature (SUN) working group activity score.16 Patients were followed up for a period of 6 months after completion of therapy (if ATT was given) or a minmum of 1 year if no ATT was given (whichever was longer).


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

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

Flowchart depicting study cohort and follow-up. n, number of study subjects; ATT, anti-tubercular treatment.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Flowchart depicting study cohort and follow-up. n, number of study subjects; ATT, anti-tubercular treatment.
Mentions: Briefly, all study subjects underwent a full systemic review, ocular examination, and standard baseline investigations — Figure 1. Blood was taken for T-SPOT.TB before TST was performed. Patients were excluded if they had (1) any other possible infectious or non-infectious cause to account for the uveitis or (2) a T-SPOT.TB result that was indeterminate as these tests cannot be interpreted. All patients were referred to the infectious diseases physician at Singapore General Hospital for review and were prescribed Anti-TB therapy (ATT) if required. Patients were followed up every 2 weeks for 8 weeks, then 2–3 monthly (or more frequently as required) to monitor response to therapy. Systemic corticosteroids were added if there was any increase in ocular inflammation after commencing ATT,15 defined as a two-step increase in inflammation using the Standardization of Uveitis Nomenclature (SUN) working group activity score.16 Patients were followed up for a period of 6 months after completion of therapy (if ATT was given) or a minmum of 1 year if no ATT was given (whichever was longer).

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