21 CFR § 874.1090 - Auditory impedance tester.

---
identifier: "/us/cfr/t21/s874.1090"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 874.1090 - Auditory impedance tester."
title_number: 21
title_name: "Food and Drugs"
section_number: "874.1090"
section_name: "Auditory impedance tester."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "H"
subchapter_name: "MEDICAL DEVICES"
part_number: "874"
part_name: "EAR, NOSE, AND THROAT 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: "51 FR 40389, Nov. 6, 1986, unless otherwise noted."
cfr_part: "874"
---


# 874.1090 Auditory impedance tester.

(a) *Identification.* An auditory impedance tester is a device that is intended to change the air pressure in the external auditory canal and measure and graph the mobility characteristics of the tympanic membrane to evaluate the functional condition of the middle ear. The device is used to determine abnormalities in the mobility of the tympanic membrane due to stiffness, flaccidity, or the presence of fluid in the middle ear cavity. The device is also used to measure the acoustic reflex threshold from contractions of the stapedial muscle, to monitor healing of tympanic membrane grafts or stapedectomies, or to monitor followup treatment for inflammation of the middle ear.

(b) *Classification.* Class II (special controls). The device, when it is a tympanometer or auditory impedance tester that complies with FDA-recognized consensus standard ANSI S3.39, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 874.9.

[51 FR 40389, Nov. 6, 1986, as amended at 84 FR 71813, Dec. 30, 2019]