WHO provides Biological Reference Materials which serve as reference sources of defined biological activity expressed in an internationally agreed unit. These preparations are the basis of a uniform reporting system, helping physicians and scientists involved in patient care, regulatory authorities and manufacturing settings to communicate in a common language for designating the activity or potency of biological preparations used in prophylaxis or therapy, and ensuring the reliability of in vitro biological diagnostic procedures used for diagnosis of diseases and treatment monitoring.

To define an internationally agreed unit to allow comparison of biological measurements worldwide

Complete guidance on the establishment of WHO reference materials, together with the catalogue of WHO reference materials and their distribution, can be found on the WHO biologicals web pages.