Whole Blood Interferon-Gamma Assay for Baseline Tuberculosis Screening among Japanese Healthcare Students
2007

Evaluating Tuberculosis Screening Tests in Japanese Healthcare Students

Sample size: 207 publication 10 minutes Evidence: moderate

Author Information

Author(s): Hotta Katsuyuki, Ogura Toshio, Nishii Kenji, Kodani Tsuyoshi, Onishi Masaru, Shimizu Yukito, Kanehiro Arihiko, Kiura Katsuyuki, Tanimoto Mitsune, Tobe Kazuo

Primary Institution: Okayama University, Okayama, Japan

Hypothesis

The whole blood interferon-gamma assay (QFT) is more accurate than the tuberculin skin test (TST) for tuberculosis screening in Japanese healthcare students at low risk for infection.

Conclusion

The QFT test yielded discordant results compared to the TST, likely due to the low specificity of the TST in BCG-vaccinated individuals.

Supporting Evidence

  • The agreement between the QFT and TST results was poor, with positive result rates of 1.4% vs. 27.5%.
  • The specificity of the blood assay was calculated as 96.6%, while the TST had a specificity of 17.6% for induration ≥5 mm.
  • The study found that the change in interleukin-10 levels after exposure to specific antigens was inversely associated with changes in interferon-gamma levels.

Takeaway

This study looked at two tests for tuberculosis in Japanese healthcare students and found that one test gave very different results than the other, which might be because many students had been vaccinated.

Methodology

Healthcare students received both the TST and QFT tests to compare their results, and interleukin-10 levels were measured before and after exposure to specific antigens.

Potential Biases

Selection bias due to a high non-response rate may have affected the positive rates of the TST and blood assay.

Limitations

The study did not fully assess the sensitivity of the blood assay due to a low number of subjects with active tuberculosis and had a high non-response rate.

Participant Demographics

{"gender":{"male":75,"female":132},"median_age":{"value":20,"range":"18-42"},"student_groups":{"medical_students":42,"nursing_students":107,"dental_students":44,"postgraduate_students":14}}

Statistical Information

P-Value

p=0.046

Confidence Interval

95% confidence interval: 0.737–2.818

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0000803

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