J Lab Med Qual Assur.  2017 Jun;39(2):97-105. 10.15263/jlmqa.2017.39.2.97.

Development and Performance Evaluation of External Quality Controls for Allergen-Specific Immunoglobulin E Tests

Affiliations
  • 1Department of Laboratory Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. ejoh@catholic.ac.kr
  • 2Samkwang Medical Laboratories, Seoul, Korea.
  • 3Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul, Korea.

Abstract

BACKGROUND
Many companies have developed different methods and products for allergen-specific immunoglobulin E (IgE) tests. Because there is no standardised reference method, external quality assessment (EQA) is important for allergen-specific IgE test to ensure the comparability and reliability of the results from different laboratories. We prepared specimens for EQA of allergen-specific IgE tests and evaluated their stability.
METHODS
Four pooled sera with 24 selected allergen-specific IgE levels were prepared and stored at −80℃. The stability of allergen-specific IgE levels was assessed on days 1, 7, and 14 at −20℃, 2℃ to 8℃, and 20℃ to 25℃, and then after 3 months at −80℃. Mock proficiency tests were performed with the four sets of prepared external quality controls for six laboratories, using the commercial multiple allergen simultaneous test (MAST) methodology.
RESULTS
About 150 specimens (650 µL each) for EQA were prepared; randomly selected specimens showed similar IgE levels for the 24 allergens (±1 class). The levels of allergen-specific IgE remained stable throughout the study period (P>0.05). Although mock survey results from six laboratories using four MAST assays revealed some variability with a difference (2-3 class), no consistent differences were observed through the allergens or MAST methods. Qualitative results from the mock survey showed 85.4% (cut-off of class 1) and 81.3% (cut-off of class 2) concordance with the results from ImmunoCAP (Phadia, Sweden).
CONCLUSIONS
The pooled sera prepared for allergen-specific IgE tests might be adequate and useful for EQA.

Keyword

Pooled serum; Allergen-specific immunoglobulin E; Stability; External quality control

MeSH Terms

Allergens
Immunoglobulin E*
Immunoglobulins*
Methods
Quality Control*
Allergens
Immunoglobulin E
Immunoglobulins
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