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 platelet and leukocyte response is one of them. It is the most direct read on whether a surface is pulling platelets out of circulation, which is the mechanism behind device-associated thrombocytopenia.
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 neither platelet nor leukocyte counts show a significant reduction attributable to the device, measured against the concurrent negative control.
What it does not tell you
A stable count does not mean the platelets are unactivated — activation markers are a separate measurement. It also says nothing about hemolysis, complement or clotting 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. Human whole blood is exposed to the device or a representative sample, and platelet and leukocyte counts after exposure are compared with the concurrent negative control. 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
PTT for the coagulation arm and complement activation for the immune arm, plus hemolysis as the baseline blood-damage test.
