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For biocompatibility tests requiring hemocompatibility, we offer multiple test types dependent on your product type and data needs, including Hemolysis, PTT, Complement Activation and In Vivo Thrombogenicity. These tests comply with the ISO 10993 biocompatibility guidelines.

Download the biocompatibility test matrix. [Based on ISO 10993-1:2010 (E) and FDA “Use of international standard ISO 10993-1”]

Applicable Standards

  • ISO 10993-4
  • ASTM F756

Hemolysis Test

The Hemolysis test is designed to determine the hemolytic properties of a medical device/material. This test is performed on medical devices/materials that have direct or indirect blood contact and fulfills hematological testing requirements for selection of tests for interactions with blood. Nelson Labs tests with fresh human blood rather than rabbit blood.

PTT Test

The Partial Thromboplastin Time (PTT) test is a general screening test for the detection of coagulation abnormalities in the intrinsic pathway. This test is performed on devices/materials that have direct contact with circulating blood.

Complement Activation

The Complement Activation test is used to determine the potential for activation of the complement system by a medical device. This humoral immune response, caused by the introduction of a foreign material into the body, can lead to adverse effects such as tissue damage. This test was designed to fulfill the immunology testing requirement for selection of tests for interactions with blood. Nelson Labs includes three time points in the assay to look at possible levels of activation over time.

In Vivo Thrombogenicity Test

The In Vivo Thrombogenicity test determines a comparative thrombo-resistant for medical devices that are intended for blood contact. This test enables manufacturers to see if the medical devices cause any potentially undesirable effects on humans, such as activation of platelets, formation of a thrombus, embolism, or injury to cells.

Testing Locations

Study Outline


The Hemolysis procedure was designed to determine the hemolytic properties of the test sample. The procedure involves exposing the test material or material extract to a blood cell suspension and then determining the amount of hemoglobin released. The test is performed using citrated human blood.

ASTM F 756-13 recommends that both tests (extract and direct contact) be performed unless the material application or contact time justifies the exclusion of one of the tests. If an extract test is being performed, please include the extraction parameters when you submit your samples.

Partial Thromboplastin Time (PTT)

The Partial Thromboplastin Time (PTT) assay was developed from the plasma recalcification and uses a PTT reagent as a platelet substitute. The sample is exposed to citrated plasma for 60 minutes at a validated temperature. The exposed plasma is divided into six replicates and incubated at 37 ± 1°C for three minutes.

The PTT reagent is then added, followed by the addition of a calcium chloride solution which inactivates the anticoagulant and allows a clot to form. The amount of time elapsed prior to the clot formation is monitored and recorded. Evaluation of the clotting times is performed using statistical comparisons to the controls.

Complement Activation

The Complement Activation test is performed in vitro using commercially prepared Enzyme Immunoassay (EIA) kits that detect the presence of specific complement proteins:

  • C3a: An enzyme generated during the activation of the complements system via the classical or the alternate pathway
  • SC5b-9-complex: The soluble, nonlytic form of Terminal Complement Complex (TCC) generated as a consequence of activation of the complement system

In Vivo Thrombogenicity

In Vivo Thrombogenicity
The In Vivo Thrombogenicity test generates safety data for a blood-contacting device. While in use, blood-contacting medical device interactions may have potentially undesirable effects on humans. This test is designed to determine the comparative thromboresistance of a medical device intended for blood contact by implanting the test article in the venous system of a canine study model. Its performance is then compared to an appropriate negative control device.

If you have additional questions about Hemocompatibility Testing, or would like to consult with the experts at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.