Blood products and related biologicals

International reference materials

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

WHO provides International Biological Reference Preparations which serve as reference sources of defined biological activity expressed in an internationally agreed unit.

These preparations are the basis for a uniform reporting system, helping physicians and scientists involved in patient care, regulatory authorities and manufacturers to communicate in a common language for:

  • designating the activity or potency of blood derived products used in prophylaxis or therapy
  • ensuring the reliability of in vitro biological diagnostic procedures used for diagnosis of diseases and treatment monitoring

This concept of using well-characterized preparations as global measurement standards against which batches of biological products are assessed remains fundamental to ensuring the quality of biological products as well as the consistency of production and are essential for establishment of appropriate clinical dosing. These preparations are generally intended for use in the characterization of the activity of secondary reference preparations (regional, national or in-house working standards). They are made for use in laboratory assays only and should not be administered to humans.


The responsibility for the establishment of WHO International Biological Reference Preparations lies with the WHO Expert Committee on Biological Standardization (ECBS).

The establishment process involves a number of steps summarized as follows:

  • The need for an International Biological Reference Preparation is recognized by scientific and medical community worldwide.
  • On the basis of this a case is formally made by the WHO Secretariat to the ECBS.
  • Working groups of experts set the priorities and characteristics for selection of the candidate reference preparations.
  • An international collaborative study is carried out before any candidate reference preparation may be considered for establishment by the WHO ECBS.
  • An internationally agreed unit is attributed to the first International Reference Preparation for biological activity characterization. The continuity of such unit is ensured by replacement with a new batch of reference preparation which must be calibrated against the first or previous reference preparation.
  • In all cases such studies must show that the proposed materials are suitable to serve as a WHO International Biological Reference Preparations in terms of stability and reliability of the materials.
  • The Biological Standardization (BS) document which reports the international multi-method collaborative study is peer-reviewed by group of experts and international scientific forums before being submitted to the WHO ECBS.

The document supporting the establishment of the Reference Preparation (BS doc) is held at WHO and can be obtained on request to the biological program.

WHO International Reference Materials

Related documents

Documents supporting establishment of reference preparations

Related links


World Health Organization
Department of Essential Medicines and Health Products
20 Avenue Appia
1211, Geneva 27