21 CFR 58.35
Quality assurance unit
21 CFR 58.35 is the regulation titled “Quality assurance unit” in 21 CFR Part 58, Good Laboratory Practice for Nonclinical Laboratory Studies. Since 2021, 11 FDA warning letters have cited it.
- Letters citing it
- 11 since 2021
- Jan 1 to Oct 30, 2026
- 2 against 2 on the same dates in 2025
- Most often cited with
- 21 CFR 58.33, in 8 letters
- Closed out
- 18% of these letters have a published close-out
Letters citing it, by year issued
Most are medical device letters (5 of 11). 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 58.35 most often, as written in the letters.
- 2 lettersFailure of the Quality Assurance Unit (QAU) to maintain a copy of a master schedule sheet of all nonclinical laboratory studies conducted at the testing facility indexed by test article and containing the test system,…
- 1 letterFailure of the Quality Assurance Unit (QAU) to determine that no deviations from approved protocols or SOPs were made without proper authorization and documentation [21 CFR 58.35(b)(5)]
- 1 letterFailure of the Quality Assurance Unit (QAU) to fulfill responsibilities [21 CFR 58.35(a),58.35(b)(1), 58.35(b)(5), and 58.35(b)(6)]
The regulation
Read the text of 21 CFR 58.35 (eCFR, as of Sep 1, 2026)
(a) A testing facility shall have a quality assurance unit which shall be responsible for monitoring each study to assure management that the facilities, equipment, personnel, methods, practices, records, and controls are in conformance with the regulations in this part. For any given study, the quality assurance unit shall be entirely separate from and independent of the personnel engaged in the direction and conduct of that study.
(b) The quality assurance unit shall:
(1) Maintain a copy of a master schedule sheet of all nonclinical laboratory studies conducted at the testing facility indexed by test article and containing the test system, nature of study, date study was initiated, current status of each study, identity of the sponsor, and name of the study director.
(2) Maintain copies of all protocols pertaining to all nonclinical laboratory studies for which the unit is responsible.
(3) Inspect each nonclinical laboratory study at intervals adequate to assure the integrity of the study and maintain written and properly signed records of each periodic inspection showing the date of the inspection, the study inspected, the phase or segment of the study inspected, the person performing the inspection, findings and problems, action recommended and taken to resolve existing problems, and any scheduled date for reinspection. Any problems found during the course of an inspection which are likely to affect study integrity shall be brought to the attention of the study director and management immediately.
(4) Periodically submit to management and the study director written status reports on each study, noting any problems and the corrective actions taken.
(5) Determine that no deviations from approved protocols or standard operating procedures were made without proper authorization and documentation.
(6) Review the final study report to assure that such report accurately describes the methods and standard operating procedures, and that the reported results accurately reflect the raw data of the nonclinical laboratory study.
(7) Prepare and sign a statement to be included with the final study report which shall specify the dates inspections were made and findings reported to management and to the study director.
(c) The responsibilities and procedures applicable to the quality assurance unit, the records maintained by the quality assurance unit, and the method of indexing such records shall be in writing and shall be maintained. These items including inspection dates, the study inspected, the phase or segment of the study inspected, and the name of the individual performing the inspection shall be made available for inspection to authorized employees of the Food and Drug Administration.
(d) A designated representative of the Food and Drug Administration shall have access to the written procedures established for the inspection and may request testing facility management to certify that inspections are being implemented, performed, documented, and followed-up in accordance with this paragraph.
[43 FR 60013, Dec. 22, 1978, as amended at 52 FR 33780, Sept. 4, 1987; 67 FR 9585, Mar. 4, 2002]
Text from eCFR as of Sep 1, 2026.
Cited alongside it
Regulations that appear in the same letters as 21 CFR 58.35.
- 21 CFR 58.33Study director8 letters cite both
- 21 CFR 58.81Standard operating procedures6 letters cite both
- 21 CFR 58.202Grounds for disqualification5 letters cite both
- 21 CFR 58.185Reporting of nonclinical laboratory study results4 letters cite both
- 21 CFR 58.31Testing facility management4 letters cite both
- 21 CFR 58.90Animal care4 letters cite both
- 21 CFR 58.130Conduct of a nonclinical laboratory study3 letters cite both
- 21 CFR 58.190Storage and retrieval of records and data2 letters cite both
Latest letters citing it
The 3 letters citing 21 CFR 58.35 that FDA posted most recently.
- DrugsView Lovelace Biomedical Research Institutenonclinical laboratory studiesIssuedOct 6, 2026PostedOct 13, 2026
- 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
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Counts include every citation in a letter, as the Letters filter does. How this database is built.