Section 864.5400 - Coagulation instrument(a)Identification. A coagulation instrument is an automated or semiautomated device used to determine the onset of clot formation for in vitro coagulation studies.(b)Classification. Class II (special controls). A fibrometer or coagulation timer intended for use with a coagulation instrument is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 864.9 .45 FR 60598, Sept. 12, 1980, as amended at 84 FR 71799 , Dec. 30, 2019