21 CFR § 864.7750 - Prothrombin time test.

---
identifier: "/us/cfr/t21/s864.7750"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 864.7750 - Prothrombin time test."
title_number: 21
title_name: "Food and Drugs"
section_number: "864.7750"
section_name: "Prothrombin time test."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "H"
subchapter_name: "MEDICAL DEVICES"
part_number: "864"
part_name: "HEMATOLOGY AND PATHOLOGY DEVICES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 351, 360, 360c, 360e, 360j, 360 371."
cfr_part: "864"
---


# 864.7750 Prothrombin time test.

(a) *Identification.* A prothrombin time test is a device used as a general screening procedure for the detection of possible clotting factor deficiencies in the extrinsic coagulation pathway, which involves the reaction between coagulation factors III and VII, and to monitor patients receiving coumarin therapy (the administration of one of the coumarin anticoagulants in the treatment of venous thrombosis or pulmonary embolism).

(b) *Classification.* Class II (performance standards).

[45 FR 60626, Sept. 12, 1980]