World Health Organisation international standards are the primary standards for an analyte. They should not be used in routine assays. They are supplied as primary standards which can be used to calibrate secondary standards.
These secondary standards may be national standards, regional standards or working reference materials used routinely in the laboratories of manufacturers, regulatory authorities or others. In this way the potency of biological medicinal products is calibrated and traceable to the WHO primary standard.
For some frequently used standards, ‘working standards’ have been prepared at NIBSC which can be supplied in greater quantities, typically in multiples of 5. These are intended for use as direct in-house reference materials.
Working standards are mainly blood product and transfusion reference materials . There are currently over 10 working standards available.NIBSC working standards
CE-marked working standards are mainly serology and nucleic acid testing standards for blood virus testing, together with some products for use in flow cytometry and anti-HLA. There are currently over 20 CE marked working standards availableCE-marked working standards
There are currently over 200 other non-WHO standards available.