Non-pretreatment digoxin assays and developments in immunoanalyzers

Area of Science:

• Clinical Chemistry
• Immunoassay Technology
• Therapeutic Drug Monitoring

Background:

• Digoxin is a critical medication for managing cardiac arrhythmias.
• Accurate therapeutic drug monitoring is essential for optimizing digoxin efficacy and minimizing toxicity.
• Advancements in immunoassay technology aim to improve the speed and reliability of drug level testing.

Purpose of the Study:

• To evaluate the performance of a new, non-pretreatment digoxin assay on the Abbott IMx analyzer.
• To determine the assay's reliability and suitability for routine clinical use in long-term care facilities.
• To compare the new assay's operational characteristics with existing immunoanalyzer generations.

Main Methods:

• Assessed within-run and day-to-day precision and the limit of detection.
• Evaluated the effect of digoxin-like immunoreactive factors and carryover.
• Compared results from the new IMx digoxin assay against the Dade Stratus II digoxin test using patient serum samples.

Main Results:

• The assay exhibited a limit of detection of 0.27 ng/mL and day-to-day precision between 3.4% and 5.9% CV.
• Linear regression showed strong correlation with the reference method (r = 0.9776).
• No significant interference was observed from digitoxin-like immunoreactive factors.

Conclusions:

• The Abbott IMx non-pretreatment digoxin assay meets manufacturer specifications.
• The assay demonstrates favorable performance compared to other automated digoxin tests.
• The evaluated digoxin assay is suitable for routine clinical application in therapeutic drug monitoring.