Methods for assaying viability of frozen-thawed granulocytes.

Phagocytosis and microbial killing by granulocytes is a complicated process which is not yet completely understood. Innumerable in vitro and in vivo tests have been outlined for the several stages of granulocyte activity leading to microbial killing. No single simple test is sufficient to determine the nature of the lesion observed in abnormal frozen and thawed granulocytes, Several procedures are required to define such lesions before attempts can be made to inhibit or reverse this damage. The tests most commonly in use measure production, mobilization, chemotaxis, opsonization, phagocytosis, degranulation, peroxidation, and microbial killing. A test of microbial killing, either in vitro or in vivo, should always be used as the definitive assay.