21 CFR § 866.5870 - Thyroid autoantibody immunological test system.

---
identifier: "/us/cfr/t21/s866.5870"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 866.5870 - Thyroid autoantibody immunological test system."
title_number: 21
title_name: "Food and Drugs"
section_number: "866.5870"
section_name: "Thyroid autoantibody immunological test system."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "H"
subchapter_name: "MEDICAL DEVICES"
part_number: "866"
part_name: "IMMUNOLOGY AND MICROBIOLOGY 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."
regulatory_source: "47 FR 50823, Nov. 9, 1982, unless otherwise noted."
cfr_part: "866"
---


# 866.5870 Thyroid autoantibody immunological test system.

(a) *Identification.* A thyroid autoantibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the thyroid autoantibodies (antibodies produced against the body's own tissues). Measurement of thyroid autoantibodies may aid in the diagnosis of certain thyroid disorders, such as Hashimoto's disease (chronic lymphocytic thyroiditis), nontoxic goiter (enlargement of thyroid gland), Grave's disease (enlargement of the thyroid gland with protrusion of the eyeballs), and cancer of the thyroid.

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