When this test applies
Required wherever the device contacts circulating blood, under ISO 10993-1:2025. ISO 10993-4 does not prescribe one test — it sets out which blood-interaction categories apply to which device type, and hemolysis is one of them. Running both arms together is the more defensible design where the device presents both a surface and a leachables risk, which is most blood-contacting devices.
When to run it
After cytotoxicity, and once the material set and surface finish are settled. Blood interaction is sensitive to surface topography and to processing residues, so running it on a material you still intend to change tends to buy a result you have to repeat.
What a pass tells you
That the hemolytic index falls in the 0 to 2% non-hemolytic band for both arms — direct contact and extract. A slightly hemolytic or hemolytic result on either arm fails the study.
What it does not tell you
Hemolysis is one blood-interaction category. It says nothing about complement activation, platelet and leukocyte effects, or coagulation time. ISO 10993-4 may call for several of the blood-interaction tests together, and a pass on one says nothing about the others.
Method
Testing per ISO 10993-4:2017 with ASTM F756. The device is placed in direct contact with rabbit blood and a single extract is run in parallel, and the hemolytic index of each is determined against concurrent controls. Extraction ratios follow ISO 10993-12: 6 cm²/mL for material under 0.5 mm thick, 3 cm²/mL at 0.5 mm or thicker, or 0.1 to 0.2 g/mL where surface area is indeterminate.
Where it runs
This method is internationally sourced. The laboratory is ISO/IEC 17025 accredited and GLP certified, and the report is issued under Groenakker cover, in Groenakker’s report template or in your document template on request at no extra cost.
Usually ordered alongside
Complement activation, platelet and leukocyte counts, and PTT, depending on which categories ISO 10993-4 assigns to your device type.
