Clinical and Laboratory Standards Institute document I/LA34-P - Design and Validation of Immunoassays for Assessment of Human Allergenicity of New Biotherapeutic Drugs; Proposed Guideline provides a framework for the design and validation of a qualitative immunoassay that detects human IgE antibody to new drugs in various body fluids and tissue extracts. It addresses technical challenges that are uniquely associated with the development of an assay that detects drug-specific IgE antibody in human blood and tissue extracts. It provides an approach for validation of an assay in the absence of a positive drug-specific human IgE antibody serum, which involves a feasibility study phase and then development and validation, using a concomitantly established drug-specific human IgG antibody assay as part of its quality control (QC) program. This guideline is intended for use by clinical and laboratory investigators who are involved in generating preclinical data and performing clinical trials involving new biotherapeutic drugs. It is also intended as a guideline for administrators of manufacturer safety programs, and government regulators who are required to critique IgE antibody assay methods and assess the validity of allergenicity data that have been submitted by innovator pharmaceutical investigators as part of a governmental licensing process for a new drug.