Longitudinal assessment of an ELISPOT test for Mycobacterium tuberculosis infection
2007

Longitudinal Assessment of an ELISPOT Test for Tuberculosis Infection

Sample size: 740 publication Evidence: moderate

Author Information

Author(s): Philip C. Hill, Roger H. Brookes, Annette Fox, Dolly Jackson-Sillah, David J. Jeffries, Moses D. Lugos, Simon A. Donkor, Ifedayo M. Adetifa, Bouke C. de Jong, Alex M. Aiken, Richard A. Adegbola, Keith P. McAdam

Primary Institution: Bacterial Diseases Programme, Medical Research Council Laboratories, Banjul, The Gambia

Hypothesis

How does the ELISPOT test perform longitudinally compared to the tuberculin skin test in detecting Mycobacterium tuberculosis infection?

Conclusion

Both ELISPOT conversion and reversion occur after exposure to M. tuberculosis, and a negative ELISPOT test should be interpreted with caution.

Supporting Evidence

  • A quarter of initially negative participants had a positive ELISPOT result at three months.
  • ELISPOT reversion occurred in 40.2% of initially positive contacts at three months.
  • The agreement between ELISPOT and TST results was 73% at recruitment.

Takeaway

The study looked at how a blood test for tuberculosis works over time, finding that results can change a lot, so a negative result doesn't always mean you're not infected.

Methodology

The study involved repeated ELISPOT and tuberculin skin tests on contacts of tuberculosis patients over 18 months.

Potential Biases

Potential unknown sources of bias due to loss of follow-up.

Limitations

Some participants were lost to follow-up, and the study did not have a TST and ELISPOT comparison at 3 months.

Participant Demographics

Contacts of tuberculosis patients, aged 15 and older.

Statistical Information

P-Value

0.048

Confidence Interval

95% CI 1.0–5.0

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pmed.0040192

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