A rate nephelometric phenobarbital and phenytoin assay: analytical and correlation studies of a new single-point calibration immunoprecipitation inhibition method.
A new single-point calibration immunoprecipitation inhibition rate nephelometric assay for phenobarbital (PB) and phenytoin (PT) has been evaluated on the Beckman ICS-II analyzer. Within-run precision (n = 20) coefficients of variation (CV) were less than 4.0% for PB (10-44 micrograms/ml) and less than 5.7% for PT (12-34 micrograms/ml). Between-run precision CVs of pooled sera (n = 20) assay were less than 4.2% for PB (7.5-33.8 micrograms/ml) and less than 8.7% for PT (4.5-17.8 micrograms/ml). Linearity and recoveries were good over a broad range of drug levels for both assays. Excellent correlation was found with existing PB, ICS vs. EMIT on the IL Multistat III MCA (y = 1.26 + 1.00x; r = 0.994), ICS vs. Dupont aca (y = 0.832 + 1.01x; r = 0.997), and ICS vs. GLC (y = 0.08 + 0.99x; r = 0.998) methods, and PT, ICS vs. MCA (y = -1.76 + 1.04x; r = 0.985), ICS vs. aca (y = -2.02 + 1.054x; r = 0.987), and ICS vs. GLC (y = -0.26 + 0.990x; r = 0.999) methods. These assays were found to provide accurate drug analyses, good stat or batching capability, and good correlation with existing methods.
D011232:Chemical Precipitation; D002849:Chromatography, Gas / Q000379:methods; D006801:Humans; D007120:Immunochemistry; D009391:Nephelometry and Turbidimetry / Q000379:methods; D010634:Phenobarbital / Q000097:blood*; D010672:Phenytoin / Q000097:blood*; D011233:Precipitin Tests; D011933:Reagent Kits, Diagnostic
D011933:Reagent Kits, Diagnostic; D010672:Phenytoin; D010634:Phenobarbital