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677 - NOVEOS system is a good alternative to validated tests to dose specific IgE in clinical practi


ePDS04_Novel insights in allergy and clinical immunology 677 - NOVEOS system is a good alternative to validated tests to dose specific IgE in clinical practice


ABSTRACT

Authors

D. Caimmi (Unité d’allergologie, Département de Pneumologie et Addictologie, CHU de Montpellier, IDESP, UMR UA11, Inserm, Université de Montpellier, Montpellier, France), C. Cognot Pons (Département d’Immunologie, CHU de Montpellier, Montpellier, France), N. Michel (Département d’Immunologie, CHU de Montpellier, Montpellier, France), T. Vincent (Département d’Immunologie, CHU de Montpellier, Université de Montpellier, Montpellier, France), P. Demoly (Unité d’allergologie, Département de Pneumologie et Addictologie, CHU de Montpellier, IDESP, UMR UA11, Inserm, Université de Montpellier, Montpellier, France)


Background

In vitro tests to measure serum levels of allergen-specific IgE (sIgE) have been used for many years and represent a milestone in the diagnosis of type I allergic reactions. Several automated and standardized systems are currently available and require a small amount of serum, not necessarily fresh-collected. One of the most commonly used and validated system to assess the level of specific IgE in patients’ serum is the ImmunoCAP® system. We evaluated the results obtained with the NOVEOS® system and then compared them with the previously mentioned one, in a cohort of patients suffering from respiratory and IgE mediated food allergy


Method

The study was conducted at the University hospital of Montpellier (France), in 2020. To evaluate the NOVEOS® system we ran a 5-day precision study, and a LoB/LOQ testing. We compared then the results obtained by using the two different systems, by assessing the relative agreement and a Passing Bablok analysis. We performed the study on samples from 82 mono-sensitized patients. Evaluated allergens included: Dermatophagoïdes pteronyssinus (D001), Der p 1 (D202), cat dander (E001),  Phleum pratense (G006),  Phl p 1 (G205), Juniperus sabinoides (T006), peanut (F013), Ara h 2 (F423). 


Results

During the course of the evaluation over 10 days of utilization, differences were observed in the instrument performance at days 1 – 3. There was a month gap between days 5 and 6 in the evaluation. The system was re-aligned and upgraded. Results from days 6 – 10  analysis showed that, with the exception of two samples, all results exhibited coefficients of variations ranging from 3.7% to 8.7%. LoQ analysis, showed that all allergens tested exhibited an LoQ less than 0.17 kUA/L, which is the LoQ presented in the directional insert from the manufacturer. When comparing results from the NOVEOS® system and the ImmunoCAP®, the sensitivity positive agreement was 89.86%, while the specificity negative agreement was 100%. Discordances were analyzed in details. Correlation assessed by a Passing Bablok analysis showed r = 0.782 (Figure 1).

 

Conclusion

Our results suggest that the performance of the NOVEOS® system was comparable to ImmunoCAP® for all allergens evaluated. The NOVEOS® meets therefore the criteria for dosing serum specific IgE in clinical and laboratory settings and this with only 4 instead of 40 µL of sampling.

 

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