Reference and Retain Samples in Pharmaceutical Industry

Samples are retained to fulfil two purposes; 

  • To provide a sample for analytical testing 
  • To provide a specimen of the fully finished product. 

Reference sample

A sample of a batch of starting material, packaging material or finished product which is stored for the purpose of being analysed should the need arise during the shelf life of the batch concerned. 

Where stability permits, reference samples from critical intermediate stages or intermediates, that are transported outside of the manufacturer’s control, should be kept.

Retention sample

A sample of a fully packaged unit from a batch of finished product. It is stored for identification purposes. 

For example, presentation, packaging, labelling, patient information leaflet, batch number, expiry date should the need arise during the shelf life of the batch concerned. 

There may be exceptional circumstances where this requirement can be met without retention of duplicate samples e.g. where small amounts of a batch are packaged for different markets or in the production of very expensive medicinal products.

For finished products, in many instances the reference and retention samples will be presented identically. 

In such circumstances, reference and retention samples may be regarded as interchangeable.

The reference and/or retention samples serve as a record of the batch of finished product or starting material and can be assessed in the event of, for example, a dosage form quality complaint, a query relating to compliance with the marketing authorisation, a labelling/packaging query or a pharmacovigilance report.

Records of traceability of samples should be maintained and be available for review by competent authorities.

Duration of Storage

Reference and retention samples should be retained for at least one year after the expiry date. 

Unless a longer period is required under the law of the Member State of manufacture, samples of starting materials shall be retained for at least two years after the release of product. 

Packaging materials should be retained for the duration of the shelf life of the finished product concerned.

Size of Reference and Retention Samples

The reference sample should be of sufficient size to permit the carrying out, on, at least, two occasions, of the full analytical controls on the batch in accordance with the Marketing Authorisation File.

Where applicable, national requirements should be followed.

 Where a batch is packaged in two, or more, distinct packaging operations, at least one retention sample should be taken from each individual packaging operation.


  • 21CFR211.170
  • SwissMedic I-SMI.TI.03e Version 6.0

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