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# BA, BE Sample Retention Compliance Guidance
- URL: https://www.fdaweb.com/ba-be-sample-retention-compliance-guidance/
- Published: 2020-08-18T12:00:00.000Z
- Updated: 2026-09-14T16:25:22.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5147451

FDA has issued a guidance, *Compliance Policy for the Quantity of Bioavailability and Bioequivalence Samples Retained Under 21 CFR 320.28(c)*, related to the retention of reserve samples of the test article and reference standard used in an *in vivo* bioavailability (BA) and *in vivo* or *in vitro* bioequivalence (BE) study. The [document](https://www.fda.gov/regulatory-information/search-fda-guidance-documents/compliance-policy-quantity-bioavailability-and-bioequivalence-samples-retained-under-21-cfr-32038c?utm%5Fcampaign=SBIA%3A%20Samples%20Guidance%20OGD&utm%5Fmedium=email&utm%5Fsource=Eloqua) specifically addresses the requirement to retain reserve samples of sufficient quantity to permit the agency to perform five times all the release tests required in an application of supplement. It also describes the conditions under which FDA does not generally intend to take enforcement action against an applicant or contract research organization for retaining less than the quantity of reserve samples of the test article and reference standard that were used in the BA or BE study as specified in regulations.

The guidance does not apply to other requirements for retention of reserve samples such as how testing facilities must select samples for testing, how the reserve samples must be retained, and whether reserve samples are in fact representative of the test article and reference standard used in the BA or BE study. It also does not apply to the regulatory requirement to retain samples under current good manufacturing practices.

An agency [statement](http://s2027422842.t.en25.com/e/es?s=2027422842&e=364793&elqTrackId=376c7bc788024cd5a73d955f2e3dcbdc&elq=15a76989b39942a095919a4fc62c0ad1&elqaid=13853&elqat=1&ref=fdaweb.com) says FDA has determined that, with technological advances, generally a reduced quantity of reserve samples than the quantity set forth in the regulation is now sufficient for agency testing provided that the applicant retains the minimum quantity deemed by FDA to be sufficient for conducting the necessary chemical and physical examination of the samples to assure the identity and composition of the test article and reference standard as intended by the regulation.