Novel Nanofluidic IgE Assay versus a Reference Method: A Real-World Comparison.

BACKGROUND: Clinically meaningful specific IgE determination is an important step in the diagnosis of allergic diseases. While patient's history and skin prick tests are available during the medical visit, most IgE immunoassays require hours to several days to be available. Recent developments in the field of nanofluidic technology open new horizons for point-of-care management of this unmet medical need. OBJECTIVE: This study aimed to compare IgE diagnostic agreement between a nanofluidic assay (abioSCOPE®) and a laboratory reference method (Phadia Laboratory System®) in a real-world clinical setting. METHODS: Sera from 105 patients whose routine allergy diagnostic workup required a blood sampling were used to compare the novel nanofluidic IgE assay to a reference method in a blind manner for a panel of five respiratory allergens. To assess the agreement between methods, patient records were reviewed by four independent experts to establish the final diagnosis. Experts were blinded to the IgE serological method used, but had access to patient history, skin prick tests, and blood test results. RESULTS: Analytic agreement between the two methods was 81% for the tested panel of allergens (ranging from 77 to 89%). The overall agreement in clinical diagnosis decision taken by the expert panel was 94.6% with the nanofluidic IgE assay when compared to the reference method. CONCLUSION: The nanofluidic IgE assay, as determined through an evaluation based on clinical history, skin prick tests, and IgE measurement, is a valuable tool for allergy experts to identify patients' sensitization patterns at the point of care, and for routine IgE diagnostic workup.

Structured oligonucleotides for target indexing to allow single-vessel PCR amplification and solid support microarray hybridization.

The combination of molecular diagnostic technologies is increasingly used to overcome limitations on sensitivity, specificity or multiplexing capabilities, and provide efficient lab-on-chip devices. Two such techniques, PCR amplification and microarray hybridization are used serially to take advantage of the high sensitivity and specificity of the former combined with high multiplexing capacities of the latter. These methods are usually performed in different buffers and reaction chambers. However, these elaborate methods have high complexity and cost related to reagent requirements, liquid storage and the number of reaction chambers to integrate into automated devices. Furthermore, microarray hybridizations have a sequence dependent efficiency not always predictable. In this work, we have developed the concept of a structured oligonucleotide probe which is activated by cleavage from polymerase exonuclease activity. This technology is called SCISSOHR for Structured Cleavage Induced Single-Stranded Oligonucleotide Hybridization Reaction. The SCISSOHR probes enable indexing the target sequence to a tag sequence. The SCISSOHR technology also allows the combination of nucleic acid amplification and microarray hybridization in a single vessel in presence of the PCR buffer only. The SCISSOHR technology uses an amplification probe that is irreversibly modified in presence of the target, releasing a single-stranded DNA tag for microarray hybridization. Each tag is composed of a 3-nucleotide sequence-dependent segment and a unique "target sequence-independent" 14-nucleotide segment allowing for optimal hybridization with minimal cross-hybridization. We evaluated the performance of five (5) PCR buffers to support microarray hybridization, compared to a conventional hybridization buffer. Finally, as a proof of concept, we developed a multiplexed assay for the amplification, detection, and identification of three (3) DNA targets. This new technology will facilitate the design of lab-on-chip microfluidic devices, while also reducing consumable costs. At term, it will allow the cost-effective automation of highly multiplexed assays for detection and identification of genetic targets.