A comparative study of a monoclonal immunoassay reagent strip test and high pressure liquid chromatography for theophylline

Our experience with the determination of theophylline in serum using a monoclonal immunoassay reagent strip test is reported. The day-to-day precision of a series of drug assay controls (n = 74) was investigated with a mean theophylline value of 15,3 +/- 1,2 mg/l. Interference and/or cross reactivity of structurally related compounds and metabolites of theophylline was tested. Serum samples from 148 asthmatic patients who were treated with theophylline were analyzed by the SERALYZER ARIS*) reagent strip test and by high pressure liquid chromatography. A correlation coefficient of 0.99 was found between these techniques using a linear regression analysis.

The use of a rapid theophylline assay in the ambulatory setting

The Seralyzer reflectance photometer was evaluated in three ambulatory settings. Of the total 99 assays in the pediatric general medicine clinic, 47 were below the therapeutic range, and 20 patients were noncompliant. There were 13 low and nine high levels along with 22 noncompliant patients detected from a total of 109 in the allergy clinic. The physician's office documented 43 low and four high levels along with 10 noncompliant patients from 105 assays. The mean time required for Seralyzer results in both the allergy and pediatric general medicine clinic was 13 minutes. Regression analysis of both finger-stick and venipuncture split samples indicated a strong correlation between Seralyzer results and traditional methods of assay (r = 0.94 and 0.99, respectively). The Seralyzer proved accurate, timely, and simple to operate.