---
kind: "section"
citation: "21 C.F.R. § 866.4540"
title: "21"
number: "866.4540"
heading: "Immunonephelometer equipment."
url: "https://uscodex.org/cfr/21/866.4540"
---

# §866.4540. Immunonephelometer equipment.

- (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.
- (b) **Classification.** Class I (general controls). The device is exempt from the premarket notification procedures in [subpart E of part 807](/cfr/21/part807-subpartE.md) of this chapter subject to the limitations in [§ 866.9](/cfr/21/866.9.md).

## Notes

### Amendments

[47 FR 50823, Nov. 9, 1982, as amended at 54 FR 25047, June 12, 1989; 66 FR 38792, July 25, 2001]

### Authority

Authority: 21 U.S.C. 351, 360, 360c, 360e, 360j, 360 l, 371.

### Source

Source: 47 FR 50823, Nov. 9, 1982, unless otherwise noted.

### Amendments

[47 FR 50823, Nov. 9, 1982, as amended at 54 FR 25047, June 12, 1989; 66 FR 38792, July 25, 2001]