Quality control laboratory testing should be available as a part of the premarket evaluation process. It is essential that a sample be tested if the DRA has been unable, for whatever reason, to conduct a full evaluation itself. Quality control laboratory testing should also be available in cases where the evaluator has reason to question the information provided, for example to check whether an assay method will in fact work.

The sample subjected to testing should comply in all respects with the information submitted for premarket evaluation, including formulation, method and site of manufacture, quality control, and so on.

If there is no national quality control laboratory, or if the country in question lacks the facilities to test the product (e.g. because special equipment is required), contract testing by another DRA or by WHO interregional or regional laboratories is acceptable. Where national quality control laboratories do exist, operational links with peripheral laboratories (both public and private) can enhance geographical coverage.

Quality control laboratory testing of products that are already marketed, followed up by strong action when quality is found to be poor, encourages manufacturers to maintain product quality.