When this test applies
ISO 10993-1:2025 flags hemocompatibility for every device that contacts circulating blood, directly or indirectly. ISO 10993-4:2017 breaks the endpoint into categories — thrombosis, coagulation, platelets, haematology and immunology (complement) — and selects tests by device category and contact duration. Hemolysis is the one test ISO 10993-4 expects for essentially every blood-contacting device, and the indirect (extract) arm addresses leachables specifically. It is often run with the direct arm as the complete hemolysis study.
When to run it
After cytotoxicity, on finished, sterilised samples with the material and process locked. It is quick relative to the rest of the hemocompatibility set, so run it early in that campaign; an extract that lyses red cells is a materials problem you want to know about before the larger studies start.
What a pass tells you
That the hemolytic index of the extract, read against ASTM F756 under ISO 10993-4, fell in the non-hemolytic range of 0 to 2% — the pass condition. Over 2 up to 5% is slightly hemolytic and above 5% hemolytic.
What it does not tell you
An extract result says nothing about damage caused by the device surface itself in direct contact — that is the direct arm. It also says nothing about thrombosis, coagulation, platelets or complement, each of which is a separate hemocompatibility category, nor anything outside hemocompatibility.
Method
Testing per ISO 10993-4:2017 with ASTM F756. A single extract of the device is prepared and incubated with diluted rabbit blood alongside negative and positive controls; released haemoglobin is measured spectrophotometrically and expressed as a hemolytic index against the total haemoglobin of the sample. Extraction ratio follows 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 (OUS). The laboratory is ISO/IEC 17025 accredited and GLP certified, and the report is issued under Groenakker’s ISO 13485:2016 certified quality system, in Groenakker’s report template or in your document template on request at no extra cost.
Usually ordered alongside
The direct-contact arm, or the two together as complete hemolysis (GRK-4006-03), which is what most submissions expect. Complement activation, platelet and leukocyte counts and PTT where the device category calls for them, plus cytotoxicity as the baseline screen.
