Intra and inter-laboratory reproducibility of a monoclonal antibody cocktail based ELISA for detection of allergen specific IgE in dogs: Proficiency monitoring of macELISA in six laboratories

The purpose of this study was to evaluate the reproducibility of results yielded using a monoclonal antibody based ELISA for detection of allergen specific IgE when run in six separate affiliated laboratories. On two separate occasions, duplicate samples of 15 different sera pools were independently evaluated by each laboratory in a single blinded fashion. The average intra-assay variance among reactive assay calibrators in all laboratories was 6.2% (range 2.6-18.2%), while the average intra-laboratory inter-assay variance was 12.1% (range 8.0-17.1%). The overall inter-assay inter-laboratory variance was consistent among laboratories and averaged 15.6% (range 15.1-16.6%). All laboratories yielded similar profiles and magnitudes of responses for replicate unknown samples; dose-response profiles observed in each of the laboratories were indistinguishable. Considering positive/negative results, inter-assay inter-laboratory concordance of results exceeded 95%. Correlation of OD values between and among all laboratories was strong (r>0.9, p<0.001). Correlation of OD values between the two separate evaluations was also high for all allergens except olive, which was attributed to lot-to-lot differences of allergen coated wells. Collectively, the results demonstrated that the monoclonal antibody based ELISA for measuring allergen specific canine IgE is reproducible, and documents that consistency of results can be achieved not only in an individual laboratory, but between laboratories using the same monoclonal-based ELISA.     

Ultrafast mid-infrared response of YBa(2)Cu(3)O(7-delta)

Optical spectra of high-transition-temperature superconductors in the mid-infrared display a gap of in-plane conductivity whose role for superconductivity remains unresolved. Femtosecond measurements of the mid-infrared reflectivity of YBa(2)Cu(3)O(7-delta) after nonequilibrium optical excitation are used to demonstrate the ultrafast fill-in of this gap and reveal two gap constituents: a picosecond recovery of the superconducting condensate in underdoped and optimally doped material and, in underdoped YBa(2)Cu(3)O(7-delta), an additional subpicosecond component related to pseudogap correlations. The temperature-dependent amplitudes of both contributions correlate with the antiferromagnetic 41-millielectronvolt peak in neutron scattering, supporting the coupling between charges and spin excitations.     

Performance characteristics of a monoclonal antibody cocktail-based ELISA for detection of allergen-specific IgE in dogs and comparison with a high affinity IgE receptor-based ELISA

The purpose of this study was to define the operational and performance characteristics of a commercially available monoclonal antibody based (mac) ELISA for detection of allergen-specific IgE in dogs. The average intra-assay variance over 1 year was 9.7% (range 2.5–62.7%), while the interassay variance averaged 10.8% (range 8.1–13.8%). The average positive control responses observed for grass, weed, tree and mite allergens during each month remained relatively constant; the average monthly variance was 11.6% (range 8.3–19.2%) for grass pollens, 13.3% (range 9.1–20.4%) for weed pollens, 13.3% (range 9.8–18.2%) for tree pollens and 13.6% (range 8.9–18.7%) for mite allergens. The interlaboratory concordance of results for the macELISA was approximately 91%. The interlaboratory concordance of results comparing the macELISA and a high affinity IgE receptor-based ELISA was approximately 92%. The results demonstrate that the macELISA is reproducible and the results are comparable to the high affinity IgE receptor based ELISA within and between laboratories.