An improved theophylline method by EMIT on the multistat III micro centrifugal analyzer

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Biomedical Instrumentation

Background:

• Theophylline measurement is crucial for therapeutic drug monitoring.
• Existing assays may require optimization for improved precision and efficiency.
• Automation of immunoassays can enhance laboratory throughput.

Purpose of the Study:

• To optimize the Syva EMIT assay for theophylline on the Instrumentation Laboratories Multistat III Micro Centrifugal Analyzer (MCA).
• To enhance the precision, speed, and cost-effectiveness of theophylline quantification.
• To validate the modified assay against established methods.

Main Methods:

• Modified the Syva EMIT theophylline assay parameters on the MCA, including sample volume, reaction time, reagent formulation, and loading sequence.
• Programmed reagent and sample loading to align with manufacturer recommendations.
• Assessed assay precision using controls and standards.
• Performed cross-correlation analysis with a standard method (Gilford 3500).

Main Results:

• Achieved coefficient of variation (CV) values below 10% for controls and standards.
• Cross-correlation study demonstrated high agreement with the Gilford 3500 method (r=0.992, slope=0.98, y-intercept=0.07).
• The modified method proved to be precise, rapid, and cost-effective at approximately $0.63 per sample.

Conclusions:

• The optimized Syva EMIT theophylline assay on the MCA provides a precise and reliable method for therapeutic drug monitoring.
• The modifications enhance assay performance, making it suitable for routine clinical laboratory use.
• This automated approach offers a cost-effective and efficient alternative for theophylline analysis.