---
kind: "section"
citation: "21 C.F.R. § 660.51"
title: "21"
number: "660.51"
heading: "Processing."
url: "https://uscodex.org/cfr/21/660.51"
---

# §660.51. Processing.

- (a) **Processing method.**
  - (1) The processing method shall be one that has been shown to yield consistently a specific, potent final product, free of properties that would adversely affect the product for its intended use throughout its dating period.
  - (2) Anti-IgG, -C3d (polyspecific) reagents and anti-IgG products may be colored green.
  - (3) Only that material which has been fully processed, thoroughly mixed in a single vessel, and filtered shall constitute a lot. Each lot shall be identified by a lot number.
  - (4) A lot may be subdivided into sublots which shall be identified by the lot number to which has been added a distinctive prefix or suffix. If lots are to be subdivided, the manufacturer shall include this information in the license application . The manufacturer shall describe the test specifications to verify that each sublot is identical to other sublots of the lot.
- (b) **Final containers and dropper assemblies.**
  - (1) Final containers and dropper assemblies shall be clean.
  - (2) Final containers and dropper pipettes shall be colorless and sufficiently transparent to permit observation of the contents for presence of particulate matter or increased turbidity.
- (c) **Date of manufacture.** The date of manufacture shall be the date the manufacturer begins the last entire group of potency tests.

## Notes

### Amendments

[50 FR 5579, Feb. 11, 1985, as amended at 50 FR 16474, Apr. 26, 1985; 65 FR 77499, Dec. 12, 2000; 67 FR 9587, Mar. 4, 2002]

### Authority

Authority: 21 U.S.C. 321, 331, 351, 352, 353, 355, 360, 360c, 360d, 360h, 360i, 371, 372; 42 U.S.C. 216, 262, 263, 263a, 264.

### Amendments

[50 FR 5579, Feb. 11, 1985, as amended at 50 FR 16474, Apr. 26, 1985; 65 FR 77499, Dec. 12, 2000; 67 FR 9587, Mar. 4, 2002]