First fully automated immunoassay for anti-Müllerian hormone.

BACKGROUND: The increasing importance of anti-Müllerian hormone (AMH) for the assessment of ovarian reserve requires accurate AMH measurements. There have been conflicting results about the reliability of currently existing manual AMH assays. METHODS: Development of a high sensitive, fast and fully automated AMH assay on the Elecsys®/cobas e electrochemiluminescence immunoassay platform. RESULTS: Elecsys® AMH is a monoclonal two-site assay used to measure AMH in 50 µL of serum or lithium heparin plasma in about 18 min. Its measuring range is from 0.01 to 23 ng/mL. The assay detects primarily 140 kDa total AMH (proAMH and AMHN,C). Standardization was against the Beckman AMH Gen II. Recovery against the highly cited Immunotech calibration was about 90%. Within-run imprecision coefficient of variation (CV) calculated on 10 serum samples were between 0.5% and 1.8%. Repeatability and intermediate precision calculated on 14 serum samples ranged from 2.6% to 1.7% and 2.9% to 2.1%, respectively. Limit of detection (LoD) [limit of quantitation (LoQ)] was 0.01 ng/mL (0.03 ng/mL). Percent recovery in dilution studies was <10% and after mixing of high and low AMH pools 94% to 103%. Elecsys® AMH, when compared to revised AMH Gen II (or Ansh Labs ultrasensitive AMH ELISA) using 57 female serum samples yielded a correlation coefficient of 0.98 (0.97) and a slope of 0.81 (0.73). There was no evidence for sample instability or variability. Samples stored at 20-25 °C or 2-8 °C up to 7 days showed no significant storage issues. Freeze-thaw cycles or sample storage at -20 °C and -80 °C for up to 9 months was without any effect on measured AMH. CONCLUSIONS: Availability of an automated Elecsys® AMH assay offers an attractive alternative to the current manual AMH assays.

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. PATIENTS AND MEASUREMENTS: 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. CONCLUSION: 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.

First automated assay for thyrotropin receptor autoantibodies.

BACKGROUND: Hyperthyroidism in Graves' disease (GD) is often associated with the production of autoantibodies (TRAb) to the thyrotropin receptor (TSHR). Current manual second generation TRAb assays demonstrate high clinical sensitivity, but are labor-intensive and time consuming. Until recently, technical difficulties prevented the availability of an automatic TRAb assay. METHODS: Development of a fast and fully automated TRAb assay on the Elecsys/cobas e electrochemiluminescence immunoassay platform. RESULTS: A labeled thyroid-stimulating human monoclonal TSHR autoantibody (M22) was used in an automated M22-binding inhibition assay. TRAb are detected by their ability to competitively inhibit M22-binding to solubilized porcine TSHR (pTSHR). High clinical sensitivity could be maintained by assembling multiple TSHR binding sites within a soluble oligomeric immunocomplex for improved TRAb binding. Requirement of sufficient on board stability of the delicate TSHR structure in solution for several days was met by pre-complexation of the pTSHR with a capture antibody to its C-terminus in combination with the use of structure-stabilizing chemical chaperones. Total imprecision coefficient of variation (CV) at 1.71 (approximate cut-off) was found to be 11.4%. TRAb results were available within 30 min. CONCLUSIONS: Availability of a fast and automatic TRAb assay offers an attractive alternative to the manual TRAb assays for the differential diagnosis of hyperthyroidism.

Technical evaluation of the first fully automated assay for the detection of TSH receptor autoantibodies.

BACKGROUND: Graves' disease (GD) is mediated by autoantibodies which bind to the TSH receptor (TRAb). The aim of the present study was to evaluate the technical performance of the first fully automated immunoassay for TRAb detection. METHODS: The Elecsys Anti-TSHR immunoassay utilizes a porcine TSH receptor (TSHR) and the human thyroid stimulating monoclonal TSHR autoantibody M22. RESULTS: Intraassay and total imprecision CV were determined between 1.4%-14.9%, and 2.4%-28.8%, respectively. Using the 20% CV criteria the functional sensitivity was found at 0.73 IU/L. The median CV at the cut-off (1.75 IU/L) was found to be 11%. Comparison studies with five TRAb immunoassays yielded slopes and intercepts between 1.02-1.48, and -0.74-0.56, respectively. Correlation coefficients were determined between 0.895 and 0.978. ROC plot analysis of patients with GD, patients with other thyroid disorders and healthy controls revealed an AUC of 0.99 resulting in a sensitivity of 97% and a specificity of 99% at a TRAb level of 1.75 IU/L. CONCLUSION: The evaluation of the TRAb immunoassay generated homogeneous performance data and demonstrated a high degree of comparability to established TRAb assays. The automated TRAb assay represents a major improvement of thyroid testing in clinical practice.