# Performance evaluation and reference interval establishment of Abbott Alinity thyroid-stimulating hormone receptor antibody (TRAb) assay for diagnosing Graves’ disease

## TL;DR

This study tested a new thyroid antibody test for diagnosing Graves' disease and set reference ranges for healthy Chinese people.

## Contribution

Established reference intervals for TRAb assay in Chinese populations and validated diagnostic accuracy for Graves' disease.

## Key findings

- Abbott TRAb assay showed high precision with CV% ranging from 1.04% to 5.92%.
- Diagnostic accuracy for Graves' disease had an AUC of 0.999 with 98.4% sensitivity and 99.4% specificity.
- Reference intervals for healthy Chinese population were 1.56 IU/L (95th percentile) and 1.95 IU/L (97.5th percentile).

## Abstract

This study aims to evaluate the analytical and clinical performance of the Abbott Alinity TRAb chemiluminescent microparticle immunoassay and establish the reference interval for healthy Chinese populations.

The precision, analytical sensitivity and linearity of Abbott TRAb assay were verified in accordance with the Clinical and Laboratory Standards Institute guidelines. A total of 300 samples from patients with Grave’s disease (GD) and other thyroid diseases were collected for method comparison and clinical performance verification. The performance of Abbott and Snibe TRAb assays was compared to Roche TRAb assay by correlation and agreement analysis. The diagnostic performance of Abbott TRAb assay was analyzed via receiver operating characteristic (ROC) analysis. The reference interval of Abbott TRAb was established from a cohort of 366 healthy individuals.

The Abbott Alinity TRAb assay demonstrated excellent precision, with repeatability (CV%) ranging from 1.04% to 5.92%, and within-laboratory imprecision (CV%) ranging from 1.09% to 5.92%. Manufacturer-claimed limits of blank, detection, and quantification were successfully verified. Linearity was confirmed from 1.14 to 47.72 IU/L. Strong correlation was observed between Abbott and Roche assays (Spearman r = 0.972; slope = 1.060), while Snibe and Roche assays showed lower correlation (r = 0.784). Concordance analysis showed the total agreement with Roche results were 97.7% for Abbott and 96.7% for Snibe. Diagnostic accuracy of the Abbott TRAb assay for GD was high, yielding an area under curve (AUC) of 0.999, sensitivity of 98.4%, and specificity of 99.4% at an optimal cutoff of 2.89 IU/L. The upper reference limits at 95th percentile and 97.5th percentile for healthy Chinese population using Abbott TRAb assay were 1.56 IU/L and 1.95 IU/L, respectively.

This study demonstrated the robustness of Abbott Alinity TRAb CMIA in clinical use with its verified analytical and clinical performance and established the reference interval for Chinese population.