Inter-laboratory reproducibility and inter-assay correlation of the Turbo-MP™ radioimmunoassay for quantitative measurement of allergen-specific immunoglobulin E

Abstract

Rationale Turbo-MP is a quantitative radioimmunoassay that was developed for the measurement of allergen-specific immunoglobulin E. We examined the intra- and inter-laboratory reproducibility of this assay, and its correlation to another commercially available test (Pharmacia UniCAP ® 100e). Methods Thirty serum samples were selected from a serum bank and were tested on two different days at two laboratories using the same lots of reagents. Quantitation of specific IgE was done for 13 allergens ( D. pteronyssinus, D. farinae, dog epithelium, cat dander, egg white, cow's milk, cod fish, peanut, box elder, Bermuda grass, P. notatum, A. fumigatus, and A. tenuis). Correlation of quantitative results was determined by linear regression. Testing of samples using UniCAP (Pharmacia FEIA) was conducted at one laboratory. Results The data from one laboratory exhibited a correlation coefficient of 0.94 (slope 1.1) and data from the other laboratory had a coefficient of 0.99 (slope 1.1). Inter-laboratory comparisons of the data sets resulted in correlation coefficients of 0.94 to 0.96 (slope 0.9 to 1.2). The comparison of Turbo-MP and UniCAP quantitative results resulted in a correlation coefficient of >0.90 (slope 0.8 to 1.2). Conclusions We demonstrate that the Turbo-MP radioimmunoassay exhibited excellent quantitative reproducibility in runs conducted within and between laboratories and that the Turbo-MP produces results that are essentially interchangeable with the Pharmacia UniCAP system.