1.1 This practice provides a protocol for rapid, in vitro screening for alternative pathway complement activating properties of solid materials used in the fabrication of medical devices that will contact blood.

1.2 This practice is intended to evaluate the acute in vitro alternative pathway complement activating properties of solid materials intended for use in contact with blood. For this practice, "serum" is synonymous with "complement."

1.3 This practice consists of two procedural parts. Procedure A describes exposure of solid materials to a standard lot of C4-deficient guinea pig serum [C4(-)GPS], using 0.1-mL serum per 13 100-mm disposable glass test tubes. Sepharose™ is used as an example of test materials. Procedure B describes assaying the exposed serum for significant functional alternative pathway complement depletion as compared to control samples. The endpoint in procedure B is lysis of rabbit RBC in buffer containing EGTA and excess Mg⁺⁺.

1.4 This practice does not address function, elaboration, or depletion of individual complement components except as optional additional confirmatory information that can be acquired using human serum as the complement source. This practice does not address the use of plasma as a source of complement.

1.5 This practice is one of several developed for the assessment of the biocompatibility of materials. Practice F748 may provide guidance for the selection of appropriate methods for testing materials for other aspects of biocompatibility. Practice F1984 provides guidance for testing solid materials for whole complement activation in human serum, but does not discriminate between the classical or alternative pathway of activation.