Assessment of antithyroglobulin and antimicrosomal autoantibodies in patients with autoimmune thyroid disease: comparison of haemagglutination assay, enzyme-linked immunoassay and radioligand assay.
Four different assay systems for detection of antithyroglobulin (T-Ab) and thyroid antimicrosomal autoantibodies (M-Ab) were evaluated: two passive haemagglutination assays (PHA), an enzyme-linked immunoassay (ELISA) and a radioligand assay (RLA). Antibody levels measured with these methods correlated well (T-Ab: r = 0.72 to 0.88; M-Ab: r = 0.63 to 0.84; p less than 0.0001). However, when the results of the measured samples were classified as normal, slightly elevated and pathological, only 40-50% of the samples showed congruous results in all tests; 60-70% agreed in PHA and ELISA, whereas 80 to 90% corresponded in the two PHAs. RLA and ELISA gave more frequently positive results for T-Ab and negative results for M-Ab than the PHAs. Despite the lower sensitivity of the quantitative methods for M-Ab detection, they depicted more readily small changes after thyroxine treatment than the PHAs. We suggest that differences in autoantibody levels found with different methods may be due to autoantibody heterogeneity.
Engler
H
H
Department of Internal Medicine, University Hospital, Basel, Switzerland.
Staub
J J
JJ
Althaus
B
B
Ryff-deLèche
A
A
Gerber
H
H
D001323:Autoantibodies / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006386:Hemagglutination Tests; D006801:Humans; D011237:Predictive Value of Tests; D011869:Radioligand Assay; D013959:Thyroid Diseases / Q000175:diagnosis*; D013967:Thyroiditis, Autoimmune / Q000175:diagnosis*
D001323:Autoantibodies; C006606:anti-thyroglobulin; C056626:thyroid microsomal antibodies