Home
Home
Quick search
Order ImmunoCAP® Products Online About us Products ImmunoCAP Design Methodology Product Performance Binding Capacity Comparison RAST versus ImmunoCAP Methods of Assay Calibration Quantitation Requires Parallelism Dilution Recovery Linearity Testing Comparison Quantitation Requires Precision Correlation Coefficient
Quality Assessment Performance Phadia Electronic Directions For Use Phadia Automation Phadia Software U.S. Product Catalog Material Safety Data Sheets Customer Care Phadia US Careers News Journal & Web Publications Trade shows Links Site Map
Methods of Assay Calibration

Methods of Assay Calibration

 
Quantitative allergen-specific IgE antibody assay (multi-point calibration curve)

  1. Calibration to WHO IgE reference preparation (IRP) 75/502 (1)
  • ImmunoCAP Calibration design
    -  Calibrators: human IgE
    -  1 U/L ~ 2.4 ng/L IgE
    -  Permits a wider measurement range with the same initial
       slope of the WHO dose-response curves
    -  Provides quantitative patient results in kUA/L
    -  New Quantitative Specific IgE calibration range: 0 - 100 kU/L
       with detection and reportable quantitative limits of 0.1 kUA/L) (2, 3)
     
  • ImmunoCAP products produce quantitative results (except for allergen mixes and qualitative screening tests, such as Phadiatop®)

Qualitative assays (no calibration curve)

  • Results depicted as Positive or Negative based on preassigned positive threshold

Semiquantitative assays

  • Single-point calibration (negative, low moderate, high levels)
    Modified scoring system- Alternative scoring system (ASM)
     
  • Multipoint calibration curve- Class scoring system (0-5 classes)

References

  1. I/LA20-A, Vol. 17 No. 24 Evaluation Methods and Analytical Performance Characteristics of Immunological Assays for Human Immunoglobulin E (IgE) Antibodies of Defined Allergen Specificities; Approved Guideline
  2. NCCLS EP17-A Determination of Limits of Detection and Limits of Quantitation
  3. ImmunoCAP Specific IgE 0-100 Directions for Use
 
ImmunoCAP technology has been and is the method of choice for researchers and clinicians as seen in over 3000 publications. When reviewing comparison studies, beware if correlation claims are presented as "with-in Class" or "±1 Class" - this presentation can mask performance problems.
 
In 1992, the Executive Committee of the American Academy of Allergy and Immunology recommended "the arbitrary reference systems with myriad class-scoring schemes should be abandoned in favor of quantitative reporting methods where test results are reported in units that are proportional to antibody content.
 
Reference: Lockey R, Lichtestein L, Bloch K, Kaliner M, Zweiman B, Rochelesky G. Position statement. The use of in vitro tests for IgE antibody in the specific diagnosis of the IgE-mediated disorders and in the formulation of allergen immunotherapy. J Allergy Clin Immunol 1992;90:263-267.