21 CFR 58.81
Standard operating procedures
21 CFR 58.81 is the regulation titled “Standard operating procedures” in 21 CFR Part 58, Good Laboratory Practice for Nonclinical Laboratory Studies. Since 2021, 6 FDA warning letters have cited it.
- Letters citing it
- 6 since 2021
- Jan 1 to Oct 30, 2026
- 1 against 1 on the same dates in 2025
- Most often cited with
- 21 CFR 58.35, in 6 letters
- Closed out
- 0% of these letters have a published close-out
Letters citing it, by year issued
Most are medical device letters (4 of 6). 2026 runs to Oct 30, 2026. Pick a year to see its letters.
What FDA writes when it cites it
The finding headings that cite 21 CFR 58.81 most often, as written in the letters.
- 2 lettersFailure of a testing facility to have standard operating procedures in writing setting forth nonclinical laboratory study methods that management is satisfied are adequate to ensure the quality and integrity of the data…
- 1 letterFailure of the testing facility to establish standard operating procedures in writing, setting forth nonclinical laboratory study methods that management is satisfied are adequate to insure the quality and integrity of…
- 1 letterFailure of the testing facility to have standard operating procedures in writing setting forth nonclinical laboratory study methods that management is satisfied are adequate to ensure the quality and integrity of the…
The regulation
Read the text of 21 CFR 58.81 (eCFR, as of Sep 1, 2026)
(a) A testing facility shall have standard operating procedures in writing setting forth nonclinical laboratory study methods that management is satisfied are adequate to insure the quality and integrity of the data generated in the course of a study. All deviations in a study from standard operating procedures shall be authorized by the study director and shall be documented in the raw data. Significant changes in established standard operating procedures shall be properly authorized in writing by management.
(b) Standard operating procedures shall be established for, but not limited to, the following:
(1) Animal room preparation.
(2) Animal care.
(3) Receipt, identification, storage, handling, mixing, and method of sampling of the test and control articles.
(4) Test system observations.
(5) Laboratory tests.
(6) Handling of animals found moribund or dead during study.
(7) Necropsy of animals or postmortem examination of animals.
(8) Collection and identification of specimens.
(9) Histopathology.
(10) Data handling, storage, and retrieval.
(11) Maintenance and calibration of equipment.
(12) Transfer, proper placement, and identification of animals.
(c) Each laboratory area shall have immediately available laboratory manuals and standard operating procedures relative to the laboratory procedures being performed. Published literature may be used as a supplement to standard operating procedures.
(d) A historical file of standard operating procedures, and all revisions thereof, including the dates of such revisions, shall be maintained.
[43 FR 60013, Dec. 22, 1978, as amended at 52 FR 33780, Sept. 4, 1987]
Text from eCFR as of Sep 1, 2026.
Cited alongside it
Regulations that appear in the same letters as 21 CFR 58.81.
- 21 CFR 58.35Quality assurance unit6 letters cite both
- 21 CFR 58.33Study director5 letters cite both
- 21 CFR 58.202Grounds for disqualification4 letters cite both
- 21 CFR 58.31Testing facility management4 letters cite both
- 21 CFR 58.90Animal care3 letters cite both
- 21 CFR 58.185Reporting of nonclinical laboratory study results2 letters cite both
- 21 CFR 58.107Test and control article handling1 letter cites both
- 21 CFR 58.113Mixtures of articles with carriers1 letter cites both
Latest letters citing it
The 3 letters citing 21 CFR 58.81 that FDA posted most recently.
- DrugsView HealthPartners Neuroscience Center Research and Innovationinvestigational drug (b)(4)IssuedMay 19, 2026PostedJun 2, 2026
- DevicesView Palamur Biosciences Private Limitednonclinical laboratory studies for medical devicesIssuedDec 11, 2025PostedDec 30, 2025
- DevicesView Jiangsu Kerbio Medical Technology Group Co.nonclinical laboratory testing services for medical devicesIssuedJul 11, 2025PostedAug 26, 2025
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Counts include every citation in a letter, as the Letters filter does. How this database is built.