1.1 This practice provides a protocol for the assessment of hemolytic properties of materials used in the fabrication of medical devices that will contact blood. 1.2 This practice is intended to evaluate the acute in vitro hemolytic properties of materials intended for use in contact with blood. 1.3 This practice consists of a protocol for a hemolysis test under static conditions with either an extract of the material or direct contact of the material with blood. It is recommended that both tests (extract and direct contact) be performed unless the material application or contact time justifies the exclusion of one of the tests. 1.4 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 a specific application. Test Method E2524 provides a protocol using reduced test volumes to assess the hemolytic properties of blood-contacting nanoparticulate materials; this may include nanoparticles that become unbound from material surfaces. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This