Introduction
Serology plays a key role in the evaluation of celiac disease (CD).
Aims & Methods
We assessed the analytical performance for the detection of CD autoantibodies, compared with routine laboratory methods, of MosaiQ AiPlex® CD microarray (AiPlex CD. AliveDx, Switzerland) a CE-marked, novel, single-use, multiplexed microarray immunoassay, used with its fully automated proprietary system. The valuated device features the simultaneous, semi-quantitative measurement of both IgA and IgG anti-tissue transglutaminase (tTG) and IgA and IgG anti-deamidated gliadin peptide (DGP) antibodies, as well as a qualitative measurement of total IgA in human serum; however, for this study, the comparison was limited to tTG IgA and tTG IgG as no samples characterized for DGP IgA nor for DGP IgG were available. Banked, de-identified serum samples characterized as reactive or non-reactive for tTG IgA and tTG IgG as per routine methods were tested with the evaluated device. Routine methods included EliA™ Celikey® IgA (Phadia AB, Sweden), EliA™ Celikey® IgG (Phadia AB, Sweden), QUANTA® Flash h-tTG IgA (Inova Diagnostics, USA), QUANTA® Flash h-tTG IgG (Inova Diagnostics, USA), Anti-Tissue-Transglutaminase IgA (ORGENTEC Diagnostika GmbH, Germany), Anti-Tissue-Transglutaminase IgG (ORGENTEC Diagnostika GmbH, Germany) and QUANTA Lite® R h-tTG IgA ELISA (Inova Diagnostics, USA). Positive percent agreement (PPA), negative percent agreement (NPA) for individual analytes were calculated as were overall positive and percent agreements.
Results
The evaluated device identified 43 out of 45 samples characterized as reactive for tTG IgA per routine methods and 79 out of 81 samples characterized as non-reactive, for a PPA of 96% (95% CI: 84.8, 99.4) and an NPA of 98% (95% CI: 91.3, 99.7). Likewise, it identified 14 out of 18 samples characterized as reactive for tTG IgG per routine methods and 79 out of 85 samples characterized as non-reactive, for a PPA of 78% (95% CI: 52.3, 93.5) and an NPA of 93% (95% CI: 85.2, 97.3). Overall positive and negative percent agreement were 90% (95% CI: 80.4, 96.4) and 95% (95% CI: 90.7, 97.9), respectively (Table 1).
| Table 1. Agreement of the investigational microarray immunoassay with routine laboratory methods |
|---|
PPA: positive percent agreement. NPA: negative percent agreement. CI: confidence interval.
|
| Parameter / Measurand | tTG IgA | tTG IgG | Overall |
| Reactive results (n) | 45 | 18 | 63 |
| PPA | 96% | 78% | 90% |
| 95% CI | 84.8, 99.4 | 52.3, 93.5 | 80.4, 96.4 |
| Non-reactive results | 81 | 85 | 166 |
NPA
| 98%
| 93% | 95% |
| 95% CI | 91.3, 99.7 | 85.2, 97.3 | 90.7, 97.9 |
Conclusion
In the present study, the evaluated multiplexed microarray immunoassay showed high concordance with routine methods for the detection of tTG IgA and tTG IgG. This device may be considered a suitable alternative method for the serological assessment of patients under clinical suspicion of CD and has the potential to help simplifying the laboratory evaluation of this condition by simultaneously and automatically analyzing IgA and IgG isotypes of key CD markers.
Disclosure
This study was funded by AliveDx Suisse SA, Eysins, Switzerland. Gerber Gomez and Christian Fischer are AliveDx employees.