Limits...
Estimated Prevalence of Tuberculosis Infection Among a New York City Clinic Population Using Interferon-gamma Release Assays.

Stennis NL, Trieu L, Ahuja SD, Harris TG - Open Forum Infect Dis (2014)

Bottom Line: Patients who were not a case or contact at testing (general clinic patients) and who had a positive QuantiFERON-Gold In-Tube (QFT-GIT) test result were compared with those with indeterminate or negative results to identify characteristics associated with positive results.Nine percent of United States-born patients compared with 19% of foreign-born patients had a positive result.Patient characteristics associated with a positive QFT-GIT result were consistent with known TB risk factors.

View Article: PubMed Central - PubMed

Affiliation: New York City Department of Health and Mental Hygiene, Long Island City, New York.

ABSTRACT

Background: Elimination of tuberculosis (TB) in the United States requires treating not only persons with active disease but also those infected with TB. Achieving this goal requires understanding local TB infection prevalence and identifying subgroups at increased risk for infection and disease.

Methods: The study population included all patients tested with an interferon-gamma release assay (IGRA) test at New York City (NYC) public TB clinics from October 1, 2006 to December 31, 2011. Patients who were not a case or contact at testing (general clinic patients) and who had a positive QuantiFERON-Gold In-Tube (QFT-GIT) test result were compared with those with indeterminate or negative results to identify characteristics associated with positive results. New York City TB surveillance data were used to identify clinic patients later diagnosed with active TB disease.

Results: A total of 69 273 IGRA tests were conducted. Among 20 066 patients tested with QFT-GIT, 16% tested positive, 83% tested negative, and <1% were indeterminate. Of 18 481 general clinic patients, 14% had a positive QFT-GIT result. Nine percent of United States-born patients compared with 19% of foreign-born patients had a positive result. Increasing age and birth in a high-incidence country were associated with a higher likelihood of having a positive result. One patient with a negative QFT-GIT result was identified as a TB case 2 years later.

Conclusions: Using QFT-GIT data, the background prevalence of TB infection in NYC was estimated. Patient characteristics associated with a positive QFT-GIT result were consistent with known TB risk factors. Results suggest that IGRAs are reliable tests for TB infection.

No MeSH data available.


Related in: MedlinePlus

Interferon-gamma release assay tests performed and percentage of positive test results, New York City (NYC), October 2006–December 2011 (N = 69 273 tests). (a) Testing protocols were amended in 2009, limiting testing to only those individuals at highest risk for TB infection or those mandated to be tested by the NYC Health Code: contacts to TB cases; entrants to public housing, homeless shelters, and drug treatment facilities; and patients referred by outside providers.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4281800&req=5

OFU047F2: Interferon-gamma release assay tests performed and percentage of positive test results, New York City (NYC), October 2006–December 2011 (N = 69 273 tests). (a) Testing protocols were amended in 2009, limiting testing to only those individuals at highest risk for TB infection or those mandated to be tested by the NYC Health Code: contacts to TB cases; entrants to public housing, homeless shelters, and drug treatment facilities; and patients referred by outside providers.

Mentions: From October 1, 2006 to December 31, 2011, 70 386 IGRA tests were conducted; 1113 (2%) tests with missing or incomplete quantitative results were excluded, leaving a total of 69 273 tests (Figure 1). Of these, 48 495 (70%) were conducted with QFT-G and 20 778 (30%) were conducted with QFT-GIT. Figure 2 shows the total number of IGRA tests performed over the full study period and the percentage positive by quarter. The number of tests performed dropped in 2009 concurrent with the change in clinic testing policy and shortly before the switch to QFT-GIT. The percentage of test results that were positive also began to increase from this point. Overall, 9% of all test results were positive (7% QFT-G, 16% QFT-GIT); 89% were negative (91% QFT-G, 83% QFT-GIT); and 2% were indeterminate (2% QFT-G, 1% QFT-GIT).Figure 1.


Estimated Prevalence of Tuberculosis Infection Among a New York City Clinic Population Using Interferon-gamma Release Assays.

Stennis NL, Trieu L, Ahuja SD, Harris TG - Open Forum Infect Dis (2014)

Interferon-gamma release assay tests performed and percentage of positive test results, New York City (NYC), October 2006–December 2011 (N = 69 273 tests). (a) Testing protocols were amended in 2009, limiting testing to only those individuals at highest risk for TB infection or those mandated to be tested by the NYC Health Code: contacts to TB cases; entrants to public housing, homeless shelters, and drug treatment facilities; and patients referred by outside providers.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4281800&req=5

OFU047F2: Interferon-gamma release assay tests performed and percentage of positive test results, New York City (NYC), October 2006–December 2011 (N = 69 273 tests). (a) Testing protocols were amended in 2009, limiting testing to only those individuals at highest risk for TB infection or those mandated to be tested by the NYC Health Code: contacts to TB cases; entrants to public housing, homeless shelters, and drug treatment facilities; and patients referred by outside providers.
Mentions: From October 1, 2006 to December 31, 2011, 70 386 IGRA tests were conducted; 1113 (2%) tests with missing or incomplete quantitative results were excluded, leaving a total of 69 273 tests (Figure 1). Of these, 48 495 (70%) were conducted with QFT-G and 20 778 (30%) were conducted with QFT-GIT. Figure 2 shows the total number of IGRA tests performed over the full study period and the percentage positive by quarter. The number of tests performed dropped in 2009 concurrent with the change in clinic testing policy and shortly before the switch to QFT-GIT. The percentage of test results that were positive also began to increase from this point. Overall, 9% of all test results were positive (7% QFT-G, 16% QFT-GIT); 89% were negative (91% QFT-G, 83% QFT-GIT); and 2% were indeterminate (2% QFT-G, 1% QFT-GIT).Figure 1.

Bottom Line: Patients who were not a case or contact at testing (general clinic patients) and who had a positive QuantiFERON-Gold In-Tube (QFT-GIT) test result were compared with those with indeterminate or negative results to identify characteristics associated with positive results.Nine percent of United States-born patients compared with 19% of foreign-born patients had a positive result.Patient characteristics associated with a positive QFT-GIT result were consistent with known TB risk factors.

View Article: PubMed Central - PubMed

Affiliation: New York City Department of Health and Mental Hygiene, Long Island City, New York.

ABSTRACT

Background: Elimination of tuberculosis (TB) in the United States requires treating not only persons with active disease but also those infected with TB. Achieving this goal requires understanding local TB infection prevalence and identifying subgroups at increased risk for infection and disease.

Methods: The study population included all patients tested with an interferon-gamma release assay (IGRA) test at New York City (NYC) public TB clinics from October 1, 2006 to December 31, 2011. Patients who were not a case or contact at testing (general clinic patients) and who had a positive QuantiFERON-Gold In-Tube (QFT-GIT) test result were compared with those with indeterminate or negative results to identify characteristics associated with positive results. New York City TB surveillance data were used to identify clinic patients later diagnosed with active TB disease.

Results: A total of 69 273 IGRA tests were conducted. Among 20 066 patients tested with QFT-GIT, 16% tested positive, 83% tested negative, and <1% were indeterminate. Of 18 481 general clinic patients, 14% had a positive QFT-GIT result. Nine percent of United States-born patients compared with 19% of foreign-born patients had a positive result. Increasing age and birth in a high-incidence country were associated with a higher likelihood of having a positive result. One patient with a negative QFT-GIT result was identified as a TB case 2 years later.

Conclusions: Using QFT-GIT data, the background prevalence of TB infection in NYC was estimated. Patient characteristics associated with a positive QFT-GIT result were consistent with known TB risk factors. Results suggest that IGRAs are reliable tests for TB infection.

No MeSH data available.


Related in: MedlinePlus