Purpose: to determine whether the test facility has procedures designed (i) to ensure that the identity, potency, quantity and composition of test and reference substances are in accordance with their specifications, and (ii) to properly receive and store test and reference substances.

The inspector should check that:

• there are written records on the receipt (including identification of the person responsible), and for the handling, sampling, usage and storage of tests and reference substances,

• test and reference substances containers are properly labelled,

• storage conditions are appropriate to preserve the concentration, purity and stability of the test and reference substances,

• there are written records on the determination of identity, purity, composition, stability, and for the prevention of contamination of test and reference substances, where applicable,

• there are procedures for the determination of the homogeneity and stability of mixtures containing test and reference substances, where applicable,

• containers holding mixtures (or dilutions) of the test and reference substances are labelled and that records are kept of the homogeneity and stability of their contents, where applicable,

• when the test is of longer than four weeks duration, samples from each batch of test and reference substances have been taken for analytical purposes and that they have been retained for an appropriate time,

• procedures for mixing substances are designed to prevent errors in identification or cross-contamination.