Development of a simple estimation method of serum caffeine concentration using a point-of-care test kit for urinary...

Area of Science:

• Clinical Chemistry
• Toxicology
• Point-of-Care Testing

Background:

• Serum caffeine concentration is a key indicator of caffeine intoxication.
• Measuring serum caffeine in emergency departments is challenging.
• A rapid and accessible method for estimating caffeine levels is needed.

Purpose of the Study:

• To develop a simple estimation method for serum caffeine concentration.
• To utilize a point-of-care test kit for urinary caffeine.
• To provide a practical tool for assessing caffeine intoxication.

Main Methods:

• Caffeine-spiked human serum samples were diluted at various folds (10x, 20x, 50x, 100x).
• Diluted samples were applied to a point-of-care urinary caffeine test kit.
• Membrane images were scanned and processed using ImageJ software.

Main Results:

• A two-step procedure using 20x and 100x dilutions allowed classification of serum caffeine concentrations.
• Concentrations were categorized into ≤25 µg/mL, >25-≤100 µg/mL, and >100 µg/mL.
• The method was validated with postmortem blood samples from fatal caffeine intoxication cases.

Conclusions:

• A simple estimation method for serum caffeine concentration was successfully developed.
• The method employs readily available point-of-care urinary caffeine test kits.
• This approach facilitates the assessment of caffeine intoxication severity.