Comparison of homogeneous enzyme immunoassay and high-pressure liquid chromatography for the determination of theophylline concentration in serum.

A comparison of the new homogeneous enzyme-multiplied immunoassay technique (EMIT, Syva) with a high-pressure liquid chromatographic technique for the determination of theophylline concentration is presented. The accuracy, precision, and specificity of the methods were compared. In addition, 100 samples from 61 pediatric patients receiving theophylline were assayed by both methods. The accuracy, precision, and specificity of the enzyme immunoassay support the use of this method for the quantification of theophylline concentration in clinical specimens. A significant correlation (R = 0.981, P less than 0.001) was found between results generated by enzyme immunoassay and high-pressure liquid chromatography for patient samples. The regression line relating these results had an intercept of 0.22 microgram per ml, a slope of 1.05, and a standard error of the estimate of 1.36 microgram per ml.