21 CFR § 864.7735 - Prothrombin-proconvertin test and thrombotest.

---
identifier: "/us/cfr/t21/s864.7735"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 864.7735 - Prothrombin-proconvertin test and thrombotest."
title_number: 21
title_name: "Food and Drugs"
section_number: "864.7735"
section_name: "Prothrombin-proconvertin test and thrombotest."
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"
---


# 864.7735 Prothrombin-proconvertin test and thrombotest.

(a) *Identification.* The prothrombin-proconvertin test and thrombotest are devices used in the regulation of coumarin therapy (administration of a coumarin anticoagulant such as sodium warfarin in the treatment of venous thrombosis and pulmonary embolism) and as a diagnostic test in conjunction with, or in place of, the Quick prothrombin time test to detect coagulation disorders.

(b) *Classification.* Class II (special controls). The device 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 60626, Sept. 12, 1980, as amended at 84 FR 71800, Dec. 30, 2019]