Clinical and Laboratory Standards Institute report I/LA20—Analytical Performance Characteristics, Quality Assurance, and Clinical Utility of Immunological Assays for Human Immunoglobulin E Antibodies of Defined Allergen Specificities is written for laboratorians, clinicians, manufacturers, and governmental regulators (inspectors, legislators, reviewers). The report summarizes the current state of immunoglobulin E (IgE) antibody assay technology, routinely tested biological specimens, practical methods for the evaluation of human IgE antibody assay-specific reagents, QA methods, and clinical interpretation of total and allergen-specific IgE antibody results.

Immunological assays for IgE antibodies of defined specificity continue to manifest improved performance. Previous editions of I/LA20 provided a framework from which IgE assay reagent validation and QC, assay calibration, and QA have been defined. This report has been updated to serve as a more comprehensive resource for laboratorians/clinicians), manufacturers, and governmental regulators (inspectors, legislators, reviewers). The primary goal of this report is to foster harmonization and enhance the quality of IgE antibody measurements that are performed in diagnostic immunology laboratories throughout the world. As such, this report expands upon the technical and clinical utility issues covered in the first two editions. It also includes an examination of allergenic molecules used in molecular-based allergy diagnosis.

Harmonization of definitions, proficiency testing survey protocols, and QA methods have been updated. With this report, diagnostic kit manufacturers are given fundamental benchmark targets that can be used for the validation and performance improvement of IgE antibody assays. Useful strategies for assessing the quality of IgE reagents and the clearance of IgE antibody assays for use in licensed diagnostic allergy laboratories are provided for regulators and inspectors. This report incorporates the most current evidence-based information related to IgE antibody analyses.

This report defines the current state of reagents and serological assay technology used to measure total immunoglobulin E (IgE) and IgE antibodies of defined allergen specificities in human blood. This report focuses on IgE assay design and calibration, validation methods, QA of assay reagents, QC strategies, and clinical applications.

The report is designed as a general reference for laboratorians, clinicians, manufacturers, and governmental regulators (inspectors, legislators, reviewers). It provides consensus on the current state of assay technology, the appropriate biological specimens that are routinely tested, practical methods for the validation of allergen and immunological reagents, diagnostic allergy laboratory QC strategies, consensus guidelines for clearance of allergen-containing reagents by governmental regulatory agencies, and a brief examination of the clinical interpretation of IgE antibody results. It also emphasizes achievable qualification practices that have been used by manufacturers to validate the quality and test the performance of reagents and configured assay systems. Once validated by the manufacturer, additional new lot specificity testing of allergen-containing reagents purchased by the user for one of the IgE antibody autoanalyzers does not need to be repeated. I/LA20 outlines strategies and procedures that have been successfully used by clinical laboratory workers to supplement manufacturer testing and QC practices with the goal of optimizing the laboratory’s overall QA program. In addition, this report serves as a resource for inspectors and regulators who are involved in qualifying diagnostic reagents and assays and clinical immunology laboratories that perform IgE analyses.