March 20, 2013

VETERINARY SERVICES MEMORANDUM NO. 800.79

TO: Biologics Licensees, Permittees, and Applicants

Directors, Center for Veterinary Biologics

Veterinary Services Leadership Team

FROM: John R. Clifford /s/ John R. Clifford

Deputy Administrator

SUBJECT: Submission of Host Animal Serum Samples for In Vitro Potency Tests

I. PURPOSE

This memorandum provides guidance to licensees, permittees, and applicants concerning the 

Center for Veterinary Biologics (CVB) policy on submitting serum samples for in vitro

potency testing. This document describes procedures for selecting, authenticating, and 

submitting serum samples to the CVB from host animals used in the potency evaluation of 

biological products.

II. REPLACEMENT

This document replaces Veterinary Services (VS) Memorandum No. 800.79 dated October 1, 

1990, which is cancelled.

III. BACKGROUND

The regulations at title 9, Code of Federal Regulations (9 CFR) 113.6 authorize the testing of 

biological products. The Standard Requirements in 9 CFR part 113 provide for the 

submission of serum samples from host animals used in potency tests for confirmatory 

testing according to the Outline of Production or Standard Requirement. Compliance with 

this memorandum should preclude the use of additional host animals in evaluating the 

potency of biological products.

IV. POLICY

A. At least one sample of pre-vaccination and post-vaccination serum from each animal 

used in the Standard Requirement or Outline of Production potency test for each 

serial should be retained after in-house testing. The minimum serum sample size 

should be documented in an approved Outline of Production.

United States 

Department of 

Agriculture

Animal and Plant 

Health Inspection 

Service

Veterinary

Services

Washington, DC 

20250

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VETERINARY SERVICES MEMORANDUM NO. 800.79

Page 2

B. The licensee or permittee will hold retained serum samples for potential premarketing release confirmatory testing by the CVB. Serum samples should be held at 

or below -20°C and retained throughout product dating.

C. On selection of a serial for confirmatory testing, the CVB will request corresponding 

serum samples. The firm’s official government sampler should authenticate the origin 

of the serum samples, their packaging, and the shipment of the samples to the CVB. It 

is the responsibility of the licensee or permittee to ensure bleeding procedures, blood 

processing, and in-house testing comply with the regulations. Samples should be 

submitted in accordance with VS Memorandum No. 800.59.

V. IMPLEMENTATION AND APPLICABILITY

This policy is effective immediately for serum samples from host animals used in potency 

tests for evaluation of biological products. This memorandum differs from the previous 

version in that it is no longer necessary to ship accompanying serum samples with every 

product serial. The policy to ship serum only on request is a privilege for the licensee or 

permittee. At any time, the CVB may notify a licensee or permittee that serum samples from 

each serial must be submitted with product samples. The CVB will identify the basis for the 

changes which may be prompted by inspection, investigation findings, or regulatory 

compliance concerns.