Clinical evaluation of CAP System and RAST in the measurement of specific IgE

Allergy. 1992 Oct;47(5):463-6. doi: 10.1111/j.1398-9995.1992.tb00665.x.


We investigated the diagnostic value of a new in vitro test, Pharmacia CAP System (Pharmacia Diagnostics AB, Uppsala, Sweden), for the quantitative measurement of allergen-specific IgE antibodies by comparison with RAST in 2 groups of patients, 71 atopic and 48 non-atopic. In the last 20 years RAST has supplied a good diagnostic tool, but this test presents some problems, the main one being sensitivity. The new test has a solid phase able to bind even very small amounts of specific IgE and an anti-IgE tracer with very low cross-reactivity with other immunoglobulins, thus presenting more favourable conditions. From the analysis of our results, Pharmacia CAP System gave higher sensitivity (94% compared to 88% of RAST) with no loss of specificity (96% for both tests). The reliability of these results is ensured by the proper selection of patients who were all suffering from pollinosis and were clinically diagnosed as certainly hypersensitive to a single pollen. A positive trend was found between severity of asthma and levels of specific IgE for timothy. Pharmacia CAP System appears to identify a larger number of atopic patients than RAST.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Allergens
  • Antibodies, Monoclonal*
  • Capsules
  • Child
  • Evaluation Studies as Topic
  • Female
  • Humans
  • Hypersensitivity, Immediate / diagnosis*
  • Immunoglobulin E / analysis*
  • Male
  • Middle Aged
  • Plants / immunology
  • Radioallergosorbent Test*
  • Reference Standards
  • Sensitivity and Specificity
  • Serologic Tests / methods*


  • Allergens
  • Antibodies, Monoclonal
  • Capsules
  • Immunoglobulin E