Clinical value of the first automated TSH receptor autoantibody assay for the diagnosis of Graves' disease (GD): an international multicentre trial.
BACKGROUND
Most recently, a new rapid and fully automated electrochemiluminescence immunoassay for the determination of TSH receptor autoantibodies (TRAb) based on the ability of TRAb to inhibit the binding of a human thyroid-stimulating monoclonal antibody (M22) has been established.


OBJECTIVE
To evaluate this assay system in clinical routine based on an international multicentre trial and to compare the results with other established TRAb assays.


METHODS
Totally 508 Graves' disease (GD), 142 autoimmune thyroiditis, 107 subacute thyroiditis, 109 nonautoimmune nodular goitre, 23 thyroid cancer patients and 446 normal controls were retrospectively evaluated.


RESULTS
ROC plot analysis revealed an area under curve of 0.99 (95% CI: 0.99-1.0) indicating a high assay sensitivity and specificity. The highest sensitivity (99%) and specificity (99%) was seen at a cut-off level of 1.75 IU/l. Here, the calculated positive predictive value was 95%, whereas the negative predictive value was 100%. Applying the ROC plot-derived cut-off of 1.75 IU/l we found a sensitivity for TRAb positivity within the group of newly diagnosed GD patients of 97% which is in accordance to the sum of different nonautomated porcine TSH receptor-based assays with a sensitivity of 94% indicating an excellent analytical performance of the new assay format. Detailed comparison of the automated and the sum of manual assays revealed a near identical specificity.


CONCLUSIONS
Our results demonstrate that this new assay system has a high sensitivity for detecting GD and specificity for discriminating from other thyroid diseases. This assay may represent the future technology for rapid fully automated TRAb detection.
Schott
Matthias
M
Department of Endocrinology, Diabetes and Rheumatology, University Hospital Duesseldorf, Moorenstrasse 5, Duesseldorf, Germany. matthias.schott@med.uni-duesseldorf.de
Hermsen
Derik
D
Broecker-Preuss
Martina
M
Casati
Marco
M
Mas
Jordi Camara
JC
Eckstein
Anja
A
Gassner
Dieter
D
Golla
Ruth
R
Graeber
Claudia
C
van Helden
Josef
J
Inomata
Keiko
K
Jarausch
Jochen
J
Kratzsch
Jürgen
J
Miyazaki
Naoko
N
Moreno
Miguel Angel Navarro
MA
Murakami
Tsukasa
T
Roth
Heinz Jürgen
HJ
Stock
Werner
W
Noh
Jaeduk Yoshimura
JY
Scherbaum
Werner A
WA
Mann
Klaus
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001322:Autoanalysis; D001323:Autoantibodies / Q000032:analysis*; D002648:Child; D005260:Female; D006111:Graves Disease / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011989:Receptors, Thyrotropin / Q000032:analysis / Q000276:immunology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013959:Thyroid Diseases / Q000175:diagnosis / Q000276:immunology; D013964:Thyroid Neoplasms / Q000175:diagnosis; D013967:Thyroiditis, Autoimmune / Q000175:diagnosis
D001323:Autoantibodies; D011989:Receptors, Thyrotropin