Analytical and Clinical Comparison of Two Fully Automated Immunoassay Systems for the Diagnosis of Celiac Disease

Gabriella Lakos,Debby Santora,Michael Mahler,Peter Martis,Gary L Norman,Alessio Fasano,Chelsea Bentow

doi:10.1155/2014/371263

Abstract

Objective. Here we compared analytical and clinical performance characteristics of two novel automated assay systems for the detection of celiac disease (CD) specific antibodies: QUANTA Flash (INOVA Diagnostics, Inc.) and EliA (Thermo Scientific). Methods. A total of 74 biopsy-proven CD patients (2 with IgA deficiency) and 138 controls were tested by both methods. Results. Sensitivities of QUANTA Flash assays ranged from 35.1% to 90.5% and specificities from 96.4% to 99.3%, while sensitivities for EliA assays ranged from 37.8% to 90.5% (equivocal considered positive) and specificities from 97.1% to 100.0%. Good qualitative agreement was found between all assays. Thirty-four (50.0%) of the 68 QUANTA Flash h-tTG IgA positive results were higher than 10 times the upper limit of normal (ULN). In contrast, only 22.8% of the EliA tTG IgA positive samples were >10x ULN. Seventy-three (98.6%) biopsy-proven CD patients were correctly identified with the QUANTA Flash h-tTG IgA+DGP IgG combination, while 64 (86.5%) and 72 (97.3%) (depending on equivocal range) were identified with the same combination of EliA assays. Conclusion. The QUANTA Flash CD assays have outstanding clinical performance. Of particular clinical significance, in light of proposals to decrease the absolute necessity of biopsy, was the demonstration that 50% of the QUANTA Flash h-tTG IgA results were >10x ULN.

Highlights

Celiac disease (CD) is characterized by a life-long intolerance to gluten from wheat, barley, or rye
The highest sensitivity for biopsy-proven CD patients was found for the QUANTA Flash h-tissue transglutaminase (tTG) IgA (90.5%)
receiver operating characteristics (ROC) curve analysis was performed for all assays showing AUC values ranging from 0.91 to 0.98 (QUANTA Flash) and from 0.91 to 0.97 (FEIA) (Figure 1)

Summary

Introduction

Celiac disease (CD) is characterized by a life-long intolerance to gluten from wheat, barley, or rye. CD can be considered a systemic autoimmune disease with treatment involving a gluten-free diet; recent research has explored novel therapies and other dietary factors [6, 7]. The diagnosis of CD typically consists of three parts: serology, small bowel biopsy, and remission of the disease following adherence to a gluten-free diet. The serological tests for CD include assays to detect antibodies to human tissue transglutaminase (tTG), deamidated gliadin peptide (DGP, detection of antibodies to whole gliadin is not appropriate for CD diagnosis), or endomysium and are frequently followed by intestinal biopsy if positive [4, 8]. While the gold standard for the unequivocal diagnosis of CD is the demonstration of villous blunting on duodenal biopsy, increasing attention has been focused on whether serological assays could be used to significantly decrease the need for biopsy [9,10,11]

Methods

Results

Discussion

Conclusion