Hemocompatibility testing: what’s new in 2017
In 2017, the new revision of ISO 10993-4 was released. This article provides a brief overview of changes that took place in it.
ISO 10993 is used worldwide for biological evaluation of medical devices. While part 1 of the ISO 10993 provides a framework for biocompatibility testing for particular devices (based on its intended use, the nature of the contact and its duration), ISO 10993-4 provides general requirements for evaluating the interactions of medical devices with blood.
The following is a step-by-step comparison of the changes implemented in the ISO 10993-4:2017 compared with the previous version: ISO 10993-4:2009:
Five test categories were defined: Thrombosis, Coagulation, Platelets, Hematology and Complement. Particularly, separate categories were defined for “thrombosis” (in vivo) and “coagulation” (in vitro). Testing under “Thrombosis” category was required for majority of devices in contact with circulating blood.
Test categories are reorganized.
Two major categories are now defined: “Hemolysis” (with distinction made between material- and mechanical-induced haemolysis) and “Thrombosis”.
The “Thrombosis” category currently include both in vitro and in vivo testing for assessment of risk for thrombosis.
With animal welfare in mind, risk for thrombosis can now be evaluated with in vitro testing only, when it is appropriate and properly justified. Prolonged and repetitive exposure devices, as well as implanted devices, still require in vivo testing in animal model.
Laboratory tests - Principles, scientific basis and interpretation
Has been updated to cover only the most common practiced tests for assessing blood interactions.
Annex C was dedicated to hemolysis tests methods description.
Has been changed and now covers the topic of in vivo thrombosis and recommended methods for its testing.
Non-Anticoagulation Venous Implant (NAVI) vs. Anticoagulation Venous Implant (AVI) methods are discussed in details.
None (was Annex C in the previous edition)
Has been updated and now includes added information on mechanically-induced haemolysis.
Has been added to cover the topic of complement testing and best test method practices. This Annex describes in greater detail complement testing history, commercially available test kits, surface area calculation approach etc.
Annexes F and G
Have been added to present the less common tests used to assess interactions with blood and the tests that are not recommended for preclinical assessment of medical device blood interaction, respectively. Many of these methods were previously recommended by the standard; some of them are found to be less sensitive or specific while others are outdated.