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Mechanical Hemolysis Assay for Blood Contacting Devices

The Mechanical Hemolysis Assay is an in vitro test structured around the ASTM F1830 and F1841 guidelines regarding Standard Practice for Assessment of Hemolysis in Blood Pumps. This test is used to determine the hemolytic potential of blood-contacting test articles in direct comparison to a predicate device.

While the ASTM guidelines are centered around blood pumps (i.e. circulatory assist devices), this standard can be adapted to test a variety of different device types including cannulae, blood collection sets, ablation catheters and more.

The test utilizes whole blood at a standard or custom anticoagulation concentration. Donor blood may be selected from ovine, porcine or, most commonly, bovine. Human blood is also a consideration, but the amount that can be collected, as well as price, can be a limitation. To best mimic a clinical setting, the blood is used for testing within 72 hours of collection and, at request, the blood may be adjusted to a target Activated Coagulation Time (ACT) range (i.e. 350-500 seconds) and/or hematocrit range (33-37 % hematocrit).

The predicate and test devices are prepared as they would be for clinical use. An experienced Study Director is assigned to the project to ensure this and works directly with the Sponsor in custom protocol development. Peristaltic pumps, a flow meter for specified tubing sizes (1/2”, 3/8” or 1/4″), heating tables and ample benchtop space to perform testing are also provided. If a pump is included or is not needed with a device, technologists are very adaptable and experienced with customized design set-ups.

Data analysis utilizes a collection of blood samples taken at numerous time points. For a standard 6-hour exposure, blood samples are collected at baseline, followed by hourly sampling. Complete Blood Counts (CBC) are obtained via a hematology analyzer, while Plasma Free Hemoglobin (PFH – the determining factor of Hemolysis) is obtained via the Randox Clinical Analyzer. These parameters are used in determining a % Hemolysis. Additional blood parameters (various chemistries, electrolytes, and blood gases) may be obtained upon request.

The increase in PFH over time can be plotted, and a direct, statistical comparison can be made between the test and predicate devices to determine significance. The test is performed a total of five times to account for variability between blood donors and to provide sufficient data to perform statistical analysis.

How Can NAMSA Help?

The FDA recommends Mechanical Hemolysis testing for ‘new or altered device designs that affect blood flow pattern.’ While this testing is often designed around blood pump devices, it is very adaptable to allow for a wide net of blood-contacting device types to test. From previous hemolysis testing, our facility has experience with cannulae, blood collection sets, blood pumps, blood administration or storage sets, ablation catheters and other direct blood-contacting devices.

The Mechanical Hemolysis Assay is currently available at the NAMSA Minneapolis lab. If you would like to evaluate the blood damage potential of your device with experienced and knowledgeable staff, look no further than NAMSA. Contact us today and work with our experts to determine the best testing plan for your device or product.

Sarah Howard

Sarah Howard is a laboratory expert with over 10 years of experience. She currently serves as a Senior Manager of Laboratory Services with NAMSA, overseeing the in-vitro testing lab, clinical pathology lab and biocompatibility testing. She also manages the Sample Preparation Supervisors in addition to the Laboratory Service Specialists.

Brady Hendrickson

Brady Hendrickson serves as the Supervisor of the In Vitro Testing lab at Minneapolis. He has been with NAMSA for over 3 years, with in-depth experience in the scientific, sample preparation and in vitro testing departments.