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.

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:

• Look up the Certificate of Analysis for your lot of product.
• Request QC data for your lot of product.

The specificity and sensitivity of each antibody is thoroughly validated in the New Product Development stage. This is done by staining multiple target cells with either single- or multi-color analysis or by other testing approaches. The QC specifications and testing SOPs and gold standard for each product are then developed. 

The functional performance of each batch of BioLegend products is strictly QC-tested according to the established QC procedures. In general, each product is tested using the following criteria: 
 

1. Staining of 1-3 target cell types with either single- or multi-color analysis detailed in the QC specification (including positive and negative controls). The tested cells can be primary cells and/or cell lines known to be positive or negative for the target antigen.
2. Each batch product is validated by QC testing with a series of dilutions to make sure the product is working within expected antibody titer range. 
   
   
    
3. Each batch is compared to an internally established "gold standard" to maintain batch-to-batch consistency.
4. When applicable, our products are side-by-side tested with our competitors' products to make sure that BioLegend's products exceed or are at least the same quality.
5. For most tandem dye-conjugated products, color compensation is examined in order to verify tandem integrity.

BioLegend provides an extensive selection of products in addition to our flow cytometry reagents. All of these products also undergo rigorous quality control, specific to each product line, to ensure the highest level of performance.

We are always seeking feedback on the performance of our products. In order to accomplish this with a fair and broad set of data, we draw on a number of internal and external validation sources.