ASTM F1984-99(2003)

Inappropriate activation of complement by blood-contacting medical devices may have serious acute or chronic effects on the host. This practice is useful as a simple, inexpensive screening method for determining functional whole complement activation by solid materials in vitro.

This practice is composed of two parts. In Part A (Section 11), human serum is exposed to a solid material. Complement may be depleted by the classical or alternative pathways. In principle, nonspecific binding of certain complement components also may occur. The alternative pathway can deplete later acting components common to both pathways, that is components other than C1, C4, and C3 (1).⁴ In Part B (Section 12), complement activity remaining in the serum after exposure to the test material is assayed by classical pathway-mediated lysis of sensitized RBC.

Assessment of in vitro whole complement activation, as described here, provides one method for predicting potential complement activation by medical materials intended for clinical application in humans when the material contacts the blood. Other test methods for complement activation are available, including assays for specific complement components and their split products (see X1.3 and X1.4).

This in vitro test method is suitable for adoption in specifications and standards for screening solid materials for use in the construction of medical devices intended to be implanted in the human body or placed in contact with human blood.

1.1 This practice provides a protocol for rapid, in vitro screening for whole 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 whole complement activating properties of solid materials intended for use in contact with blood. For this practice, the words "serum" and "complement" are used interchangeably (most biological supply houses use these words synonymously in reference to serum used as a source of complement).

1.3 This practice consists of two procedural parts. Procedure A describes exposure of solid materials to a standard lot of human serum, using a 0.1-mL serum/13 x 100-mm disposable test tube. Cellulose acetate powders and fibers are used as examples of test materials. Procedure B describes assaying the exposed serum for significant functional whole complement depletion as compared to control samples.

1.4 This practice does not address function, elaboration, or depletion of individual complement components, nor does it 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 F 748 may provide guidance for the selection of appropriate methods for testing materials for other aspects of biocompatibility.