Standard Operating Procedures (SOPs) are followed at each step of production. Every production SOP is developed through optimization and is validated by subsequent testing. Batch records are required and documented for every batch of production from cell culture/ascites production to purification, conjugation, bottling and packaging. In addition, every stage of production is well documented in an electronic database to maintain accuracy as well as to allow traceability.


Purified antibodies are produced by affinity purification methods. To ensure reproducibility, each cell line (clone) has defined cell culture specifications and purification specifications, such as resins for purification, elution condition, and final storage buffer. Each batch of purified material is tested for purity by SDS-PAGE and IEF gel analysis. Purity is required to be 95% for IgG. Endotoxin is tested by the LAL testing method for LEAF™ (Low Endotoxin Azide Free), Ultra-LEAF™, and GoInVivo™ Purified antibodies, as well as recombinant proteins. Endotoxin tested products are guaranteed to be below the limits indicated on each TDS. If your endotoxin requirements are more stringent, BioLegend may be able to provide products with endotoxin as low as 0.001 EU/µg of protein. The specificity and activity (titer) of purified materials are tested according to QC specifications. A batch of antibody can be released only if it passes all above required testing. Furthermore, GoInVivo™ products are tested for pathogens.

Conjugate products are manufactured by following defined conjugation SOPs and specifications. Critical raw materials are fully evaluated and validated for antibody conjugation usage. Each batch of critical materials is tested and meets its specifications before release for production. Each batch of conjugated product goes through physical testing such as dye to antibody ratios and dye to dye ratios (for tandem dye conjugates) to ensure these parameters meet the production specifications and to ensure lot to lot consistency of each antibody-fluorochrome conjugate. The functional activity of each conjugate product is tested for its intended application.

Validity and Authentication of Biological Reagents

The NIH (National Institutes of Health) has recently published a notice for grant applications to enhance the reproducibility of research (NOT-OD-16-011). It requests that grant applications include information on the authentication of key biological and/or chemical resources. BioLegend takes extensive measures, including the quality control measures outlined on this page, to ensure that all research products sold by BioLegend are valid and reproducible. We also list our products on the Antibody Registry, which is part of the Resource Indentification Initiative. BioLegend's technical data sheets now display the RRID number from the Antibody Registry for easy cross-referencing.

More resources for authentication of reagents: