Pitfalls of single radial immunodiffusion techniques used for the quantification of influenza haemagglutinin.

In the case of Tween-ether split vaccines the quantification of haemagglutinin is not achievable by the single radial immunodiffusion test alone. Aggregate formation of solubilized haemagglutinin frequently occurs when the applied detergent is removed and, therefore, a physico-chemical method including an effective disaggregation procedure like SDS treatment in combination with PAGE is recommended.