Performance characteristics of 5 automated thyroglobulin autoantibody and thyroid peroxidase autoantibody assays.
BACKGROUND
Measurement of thyroid peroxidase autoantibodies (TPOAb) is useful in diagnosing patients with autoimmune thyroid disease. Measurement of thyroglobulin autoantibodies (TgAb) is used to detect potential interferences with thyroglobulin immunoassays and in limited situations for the diagnosis of autoimmune thyroid disease.


METHODS
The limit of detection, imprecision, reference interval, method comparison and diagnostic concordance for the ADVIA Centaur, ARCHITECT i2000, AxSYM, Immulite 2000, Modular E170 (TPOAb only), and UniCel DxI 800 (TgAb only) methods were evaluated. The Advantage was used as the comparison method.


RESULTS
Total imprecision ranged from 2.6% to 14.9% for TgAb and 2.1% to 15.8% for TPOAb. Passing-Bablok slopes ranged from 0.51 to 10.4 (TgAb) and 1.05 to 7.12 (TPOAb) with correlation coefficients of 0.48 to 0.82 (TgAb) and 0.66 to 0.78 (TPOAb). Assay cutoffs were adjusted using a common set of reference interval samples. Concordance with the Advantage assay using the new cutoffs was found to be improved and ranged from 68.5% to 84.7% (TgAb) and 77.5% to 84.7% (TPOAb).


CONCLUSIONS
Although all assays generally performed well, assay concordance for a negative or positive result ranged from 54.2 to 84.7%. Quantitative agreement between methods was generally poor and methods could not be used interchangeably. Additional standardization efforts are required to improve inter-method agreement.
La'ulu
Sonia L
SL
ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, United States.
Slev
Patricia R
PR
Roberts
William L
WL
D001323:Autoantibodies / Q000097:blood*; D001331:Automation; D019937:Diagnostic Techniques and Procedures / Q000592:standards*; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology*; D012015:Reference Standards; D015203:Reproducibility of Results; D013954:Thyroglobulin / Q000276:immunology*; D013967:Thyroiditis, Autoimmune / Q000175:diagnosis*
D001323:Autoantibodies; D013954:Thyroglobulin; D007453:Iodide Peroxidase