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Variable and inaccurate serum IgG4 levels resulting from lack of standardization in IgG subclass assay calibration.
- Source :
-
Clinical chemistry and laboratory medicine [Clin Chem Lab Med] 2019 Oct 25; Vol. 57 (11), pp. 1777-1783. - Publication Year :
- 2019
-
Abstract
- Background The quantification of serum IgG4 is commonly performed during the diagnostic workup of IgG4-related diseases (IgG4-RD). According to recent literature, IgG4 values above 1.35 g/L are characteristic of IgG4-RD and support its diagnosis at initial presentation. The purpose of this study was to evaluate comparability and accuracy of the two main commercially available IgG4 assays (Siemens Healthineers and The Binding Site). Methods Method comparison was performed for IgG and IgG subclasses using a collective of selected samples with elevated serum IgG4. In addition, we assessed the accuracy of both assays using purified polyclonal and monoclonal IgG4 preparations. Results Our data show significant discrepancies between the two IgG subclass assays for the measurement of IgG4 and, to a lesser extent, IgG3. Conclusions The lack of standardization between the two main providers of commercially available IgG4 assays leads to significant inter-assay result discrepancies, which might potentially cause unnecessary clinical workup. We conclude that serum IgG4 assay-specific decision limits, and not an assay-independent single cut-off level for IgG4 (e.g. 1.35 g/L), should be used when assessing patients for IgG4-RD. An internationally recognized, certified reference material for IgG subclasses is urgently needed, and assay manufactures are encouraged to undertake steps toward standardization of measurements of IgG4 and other IgG subclasses.
- Subjects :
- Female
Humans
Male
Reference Standards
Calibration standards
Immunoglobulin G blood
Subjects
Details
- Language :
- English
- ISSN :
- 1437-4331
- Volume :
- 57
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Clinical chemistry and laboratory medicine
- Publication Type :
- Academic Journal
- Accession number :
- 31188751
- Full Text :
- https://doi.org/10.1515/cclm-2019-0261