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 complement activation is one of them. It matters most for devices with large blood-contacting surface areas and extended contact — oxygenators, dialysers, circuits — where cascade activation has clinical consequences.
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 SC5b-9 generation is not significantly greater than the concurrent negative control. Worth knowing before you read a report: ISO 10993-4 sets no fixed numeric threshold here, so the conclusion rests on the comparison to controls rather than on a published limit.
What it does not tell you
Complement is one arm of the immune and coagulation response. It says nothing about hemolysis, platelet consumption or clotting time, and a device can activate complement without being hemolytic. 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. Human serum is exposed to the device or a representative sample and SC5b-9 is quantified by ELISA against concurrent negative and positive controls. Where a representative sample rather than the whole device is used, 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
Platelet and leukocyte counts and PTT, which together with this test cover the thrombosis and immune categories ISO 10993-4 defines. Hemolysis is normally run as well.
