CLSI I/LA20—Analytical Performance Characteristics, Quality Assurance, and Clinical Utility of Immunological Assays for Human Allergen-Specific Immunoglobulin E Antibodies defines the current state of allergen reagents (extracts, molecules, and epitopes) and assay technology (ie, singleplex and multiplex, manual and autoanalyzer based) used to measure total immunoglobulin E (IgE) and allergen-specific IgE antibodies (Abs) in human blood. CLSI I/LA20 examines IgE assay design, calibration, validation, and verification methods; QA of assay reagents; internal QC strategies; external proficiency testing; and clinical applications. It contrasts the advantages and disadvantages of IgE Ab serological results with those obtained by in vivo skin testing and provocation testing. Mentioned but not covered in detail is a general discussion of the clinical history-based diagnostic algorithm for human allergic disease, cell-based assays (eg, basophil and eosinophil), and immunoglobulin G (IgG)/IgG4-blocking Ab assays (eg, facilitated allergen binding assay). Important trends in IgE Ab assay technology are highlighted; these include the use of molecular allergens, multiplexed bead, fluid-phase and chip-based arrays, and allergen-specific IgE monoclonal antibodies as reference and QC reagents. CLSI I/LA20 serves as a reference for laboratory professionals, clinicians, assay manufacturers, and regulatory bodies aiming to harmonize practices and improve the accuracy of IgE Ab measurements globally.

CLSI I/LA20-Ed4 replaces CLSI I/LA20-Ed3, published in October 2016. Several changes were made in this edition, including:

• Adding a discussion of new molecular allergen and allergenic epitope-based measuring system and micro- and macro-arrays for the detection of allergen-specific IgE Ab
• Enhancing the discussion of strategies for governmental clearance of multiplex measuring systems and chip-based assays
• Updating definitions, proficiency testing survey protocols, and QA methods
• Adding a discussion of the utility of the new companion CLSI I/LA37 {1} Diagnostic Allergen Database

NOTE: The content of CLSI I/LA20 is supported by the CLSI consensus process and does not necessarily reflect the views of any single individual or organization.

CLSI I/LA20 provides recommendations on the current state of reagents and assay technology (ie, serological and molecular) used to measure total immunoglobulin E (IgE) and allergen-specific IgE antibodies (Abs) in human blood. CLSI I/LA20 focuses on IgE assay design and calibration, validation and verification methods, QA of assay reagents, QC strategies, and clinical applications. It contrasts serological results with those obtained by in vivo skin testing and provocation testing. 

The intended users of CLSI I/LA20 are health care professionals, governmental regulators and inspectors, and industrial manufacturers of allergens (extracts, molecules, epitopes) and IgE Ab assays. 

CLSI I/LA20 is not intended to cover cell-based assays involving basophils (eg, basophil activation test [BAT]) or eosinophils or immunoglobulin G (IgG)/IgG4-blocking Ab assays (eg, facilitated allergen-binding assay).