Paradox of serial interferon-gamma release assays: variability width more important than specificity size

Details

• Alternative Title:
  Int J Tuberc Lung Dis
• Personal Author:
  Stout, J. E. ; Belknap, R. ; Wu, Y-J. ; Ho, C. S.
• Corporate Authors:
  Tuberculosis Epidemiologic Studies Consortium
• Description:
  SETTING:
  
  Serial screening for latent tuberculous infection (LTBI) is commonly performed in certain populations, such as health care workers. The high apparent conversion rate in some studies of interferon-gamma release assays is puzzling given the claimed high specificity of these tests.
  
  OBJECTIVE:
  
  To understand how test-retest variability, specificity, and underlying LTBI prevalence affect observed outcomes of repeated testing for LTBI.
  
  DESIGN:
  
  Mathematical model assuming constant test sensitivity and specificity over time and no new infections.
  
  RESULTS:
  
  Test-retest variability had a large effect on the observed proportion of conversions (initial negative test, followed by a positive test) and reversions (initial positive test, followed by a negative test). For example, a test with 70% specificity and 5% test-retest variability would be associated with a conversion rate of 3.7% and a reversion rate of 7.7%, while a test with 95% specificity but 10% test-retest variability would be associated with a conversion rate of 5.5% and a reversion rate of 57%, assuming that both tests are 80% sensitive and underlying LTBI prevalence was 5%.
  
  CONCLUSION:
  
  Test-retest variability is a key parameter that should be reported for tests used for serial screening for LTBI. Reducing test-retest variability can reduce false-positive and false-negative results.
  
  
• Subjects:
  Health Personnel Humans Interferon-gamma Interferon-gamma Release Tests Latent Tuberculosis Mass Screening Models, Theoretical Reproducibility Of Results Sensitivity And Specificity
• Source:
  Int J Tuberc Lung Dis. 22(5):518-523
• Pubmed ID:
  29663956
• Pubmed Central ID:
  PMC9132738
• Document Type:
  Journal Article
• Funding:
  CC999999/ImCDC/Intramural CDC HHSUnited States/
• Volume:
  22
• Issue:
  5
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:15235a0c1297de8385493d11bed29c5aa8ca8196be8d009d4cee688f63e1f467
• Download URL:
  https://stacks.cdc.gov/view/cdc/119189/cdc_119189_DS1.pdf
• File Type:
  [PDF - 730.24 KB ]