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Developing a Certified Reference Material containing autoantibodies against vasculitis

Test tube with blood sample for anti-PR3 test
Jul 01 2019

In close collaboration with clinical scientists from the International Federation of Clinical Chemistry and Laboratory Medicine, the JRC developed a new certified reference material (CRM) consisting of specific autoantibodies for the diagnosis of small vessel-associated vasculitis.

This CRM ensures accurate results of measurements independently of the test assay used in the clinical laboratory.

The disease vasculitis is an inflammation of blood vessels. This can cause a range of symptoms and complications, as the walls of the affected blood vessels can swell, bulge and may even burst, causing bleeding insight the body.

Vasculitis belongs to the rare diseases, its exact cause is unknown. The type of vasculitis affecting the small blood vessels may be related to infections, such as those associated with hepatitis. When properly diagnosed, vasculitis can be treated with specific drugs. Therefore it is of utmost importance to make the right diagnosis early on. Screening tests are based on immunoassays.

With a diagnosis depending largely on the immunoassay selected by a laboratory, the accurate and comparable measurement of autoantibodies is very important. The discrepancy between test results, partly because of the arbitrary units used by the various immunoassays available in the market, is an issue which may lead to misdiagnosis of a patient or in the very least a delay in diagnosis.

The appropriate use of a common calibrant brings results from available immunoassays closer together, having an overall positive impact. The development of a certified reference material (CRM) includes a number of steps from finding the appropriate starting material to its characterisation. The appropriateness of a material is decided through a study known as commutability.

For the material against PR3 ANCA IgG autoantibodies, several formats of candidate materials were tested alongside several patient samples and immunoassays. The ultimate goal was to find, which material behaved as the patient samples. Careful analyses of the results lead to the choice of the format most suitable as CRM.

The chosen starting material was a plasmapheresis material from one patient donor which was transformed into serum, filled into vials and freeze dried. The homogeneity between and within a number of the vials produced was analysed as was the stability of the material for various shipment conditions but also for long-term storage.

All JRC CRMs are being monitored annually for their stability during storage. Finally, a concentration value in mg/mL (SI) was assigned to the CRM ERM-DA483/IFCC based on a value transfer protocol.

More information you find on the Reference Materials catalogue

Read more in:

E. Monogioudi et al.: "Certified reference material against PR3 ANCA IgG autoantibodies. From development to certification", Clin Chem Lab Med (2019)

DOI: 10.1515/cclm-2018-1095