U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 28, 2025
(a) Identification. A partial thromboplastin time test is a device used for primary screening for coagulation abnormalities, for evaluation of the effect of therapy on procoagulant disorders, and as an assay for coagulation factor deficiencies of the intrinsic coagulation pathway.
(b) Classification. Class II (performance standards).