Anaphylaxis: skin testing could help identify patients at low-risk for problems under general anaesthesia

Clinical bottom line (level 4)

  1. Patients with a previous severe reaction during anaesthesia who had negative skin tests (intradermal or prick testing) were very unlikely to have a problem during subsequent anaesthesia (LR-0.0) .
  2. This is based on a sample of only 17, with no incorrect assignment, but the confidence limit stretches from 0% to 19.5%
Fisher and Bowey: British Journal of Anaesthesia 1997; 79: 59-63
Expires November 2004

The study

Setting: anaesthetic allergy clinic, university hospital, Australia

135 patients (aged ?, ?% male) with systemic reactions during anaesthesia requiring vasoactive drugs, subsequently referred for investigation of a possible anaesthetic allergy

Excluded if
  • aged < 10
  • local anaesthetic allergy



    • ?independent unblinded reference standard, applied in all patients from a ?consecutive appropriate spectrum.
    Reference standard:
    • subsequent general anaesthetic (only available in 82 - 61%)
    Diagnostic test: intradermal or prick testing
    • Patients with minor reactions are not included in this CAT.

    The evidence

    pre-test probability of problematic GA: 1.2%, (95% CI: 0.01% to 6.6%)

    diagnostic test problematic GA uneventful GA LR
    (95% CI)    		 post-test probability
    skin tests 1 81 1.3
    (1.1 to 1.4)     		2%
    total 53 82

    Comments

    1. Since the study was not blinded, clinicians may well have avoided certain drugs on the basis of the skin tests - therefore the tests will appear worse than in reality.
    2. Prick testing identified a potential drug in 80% of cases, and intradermal testing in 83% of cases.

    Citation

    1. Fisher MM, and Bowey CJ: intradermal compared with prick testing in the diagnosis of anaesthetic allergy. British Journal of Anaesthesia 1997; 79: 59-63
    Contributor: Mike Bennett, Bob Phillips and Chris Ball, November 1999
    Reviewer: Malcolm Daniel

    Clinical Question.
    Patient previous severe reaction during anaesthesia
    Intervention or Exposure skin testing
    Outcome subsequent problematic GA