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Positive Control Material Introduced to ASTM Hemolysis Standard

The presence of hemolytic material in contact with the blood may cause loss of, or damage to, red blood cells and may produce increased levels of free plasma hemoglobin capable of inducing toxic effects or other effects to the kidney or other organs. ASTM F 756, Standard Practice for Assessment of Hemolytic Properties of Materials, offers medical professionals a protocol for the assessment of hemolytic properties of materials used in the fabrication of medical devices that contact blood.

Last released in 1993, ASTM F 756 has undergone major revisions including the addition of identifiable positive control materials using only chemicals or hypotonic solutions. A task group has been involved in the redraft for the past three years within Subcommittee F04.16 on Biocompatibility Test Methods under Committee F-4 on Medical and Surgical Materials and Devices. Participating in the group are representatives from industry, the U.S. Food and Drug Administration, and numerous contract labs. At this juncture, the group has done extensive feasibility work and is accumulating statistical information.

According to Task Group Chairman Regina Malczewski, Ph.D., a senior research specialist and special testing and projects group leader at Dow Corning Healthcare Industries, Midland, Mich., the task group has assessed and challenged each part of the standard with respect to viability and value. “It’s been a very interesting, but challenging process. I want to make sure we have a standard that is practical, and most importantly, that is sensitive enough.”

Significant revisions to ASTM F 756, as described by Subcommittee F04.16 Chairman Katharine Merritt, Ph.D., are:

  • A decrease in the concentration of blood used, thus greatly increasing sensitivity;
  • Identification of positive control materials;
  • Change in sequence in which the parts of the standard are presented; and
  • Deletion of the standard techniques for measuring iron as an alternative to measuring hemoglobin.

For further technical information, contact Regina Malczewski, Dow Corning Healthcare Industries Corp., Mail #C40D01, 2200 W. Salzburg Rd., Midland, MI 48686-0994 (517/496-4158; fax: 517/496-4654). Committee F-4 next meets during ASTM Committee Week, May 24-26 in Toronto, Ontario, Canada. For meeting or membership information, contact F-4 Staff Manager Teresa Cendrowska, ASTM (610/832-9718). //