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Sensitivity to sensitins and tuberculin in Swedish children. III. Sequential versus simultaneous skin testing
L O Larsson1, B E Skoogh, M W Bentzon
1Department of Pulmonary Medicine, University of Göteborg, Sweden.
Insights
Skin testing with tuberculin and sensitins yields consistent results whether performed simultaneously or sequentially. This study found no significant differences or booster effects, confirming reliability in diagnostic procedures.
Area of Science:
- Immunology
- Microbiology
- Public Health
Background:
- Tuberculin skin testing (TST) and sensitin skin testing are crucial for diagnosing mycobacterial infections.
- Assessing the consistency of results between simultaneous and sequential skin testing is important for accurate diagnosis and epidemiological studies.
Purpose of the Study:
- To evaluate the consistency of results obtained from simultaneous versus sequential skin testing with purified protein derivative (PPD) tuberculin and mycobacterial sensitins.
- To determine if a 3-day interval between sequential skin tests influences reaction rates or causes a booster effect.
Main Methods:
- A comparative study involving 475 schoolchildren (8-9 years old) undergoing sequential skin testing (3-day interval) with PPD tuberculin and either Mycobacterium avium or Mycobacterium scrofulaceum sensitin.
- Comparison of results with 470 simultaneously tested children from the same population.
- Analysis of reaction frequencies using a 6 mm cut-off for positive results.
Main Results:
- No statistically significant differences were observed in reaction frequencies between sequential and simultaneous testing groups.
- Sequential testing showed reaction rates of 3.1% (tuberculin), 19% (M. avium sensitin), and 30% (M. scrofulaceum sensitin).
- Simultaneous testing showed slightly higher reaction rates: 4.7% (tuberculin), 21% (M. avium sensitin), and 36% (M. scrofulaceum sensitin).
Conclusions:
- Simultaneous and sequential skin testing with tuberculin and sensitins provide comparable results.
- A 3-day interval between sequential tests does not appear to induce a booster effect in non-BCG-vaccinated children.
- The findings support the reliability of both testing methodologies in mycobacterial diagnostics.
Abstract:
The aim of this study was to determine whether simultaneous and sequential skin testing with tuberculin and sensitins give consistent results. A total of 475 8- or 9-year-old schoolchildren were skin tested sequentially, at an interval of 3 days, with PPD tuberculin and with either Mycobacterium scrofulaceum or M. avium sensitin. The results were compared with those of 470 simultaneously tested children chosen from the same living area. There were no statistically significant differences between the frequencies of the reactions of sequentially and simultaneously tested children. When the sequential testing procedure was employed, 3.1% reacted to tuberculin, 19% to M. avium sensitin and 30% to M. scrofulaceum sensitin, taking a 6 mm cut-off. The corresponding figures for the simultaneously tested children were 4.7, 21 and 36%, respectively. Thus, there was no indication that the simultaneous testing procedure in itself influenced the results, neither was there any sign of a booster effect when testing in sequence with an interval of 3 days in non-BCG-vaccinated children.