{"data":{"id":"us/21-cfr-866.4540","jurisdiction":"us","citation":"21 CFR 866.4540","heading":"Immunonephelometer equipment.","body":"(a) Identification. Immunonephelometer equipment for clinical use with its electrical power supply is a device that measures light scattering from antigen-antibody complexes. The concentration of these complexes may be measured by means of reflected light. A beam of light passed through a solution is scattered by the particles in suspension. The amount of light is detected by a photodetector, which converts light energy into electrical energy. The amount of electrical energy registers on a readout system such as a digital voltmeter or a recording chart. This electrical readout is called the light-scattering value and is used to measure the concentration of antigen-antibody complexes. This generic type of device includes devices with various kinds of light sources, such as laser equipment.\n(b) Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 866.9.","path":["Title 21—Food and Drugs","CHAPTER I—FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER H—MEDICAL DEVICES","PART 866—IMMUNOLOGY AND MICROBIOLOGY DEVICES","Subpart E—Immunology Laboratory Equipment and Reagents"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-21.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:47Z","sha256":"7dd717527083b184b88c1f7026a900b146aeb77bc0b5d6a1a69234dd71440e75","source_id":"us-cfr","stale":true,"prev":"us/21-cfr-866.4520","next":"us/21-cfr-866.4600"},"notice":"GroundRules: Original legal text. Not legal advice."}