U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 28, 2025
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All TitlesTitle 21Chapter IPart 864Subpart H - Subpart H—Hematology Kits and Packages
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(a) Identification. A platelet factor 4 radioimmunoassay is a device used to measure the level of platelet factor 4, a protein released during platelet activation by radioimmunoassay. This device measures platelet activiation, which may indicate a coagulation disorder, such as myocardial infarction or coronary artery disease.
(b) Classification. Class II (performance standards).
