Sample evaporation from pierceable cups: still an important source of analytical error

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Laboratory Medicine

Background:

• Sample evaporation is a common issue in laboratory practice.
• Evaporation can significantly alter analytical results.
• Preventive measures are crucial for accurate diagnostics.

Purpose of the Study:

• To quantify the impact of sample evaporation on key analytes.
• To evaluate the effectiveness of different sample configurations and handling.
• To identify strategies for minimizing analytical errors caused by evaporation.

Main Methods:

• Plasma samples (n=10) were analyzed for glucose, sodium (Na+), bicarbonate (HCO3-), and calcium.
• Samples were tested in six different configurations over a 2-hour period.
• Measurements were taken at five distinct time points to track changes.

Main Results:

• Glucose, Na+, and calcium concentrations increased over time due to evaporation.
• Bicarbonate (HCO3-) levels decreased significantly with time.
• Observed changes were clinically significant, impacting potential diagnoses.

Conclusions:

• Sample evaporation introduces significant analytical error.
• Proper sample handling is essential to reduce evaporation-related inaccuracies.
• Pierceable caps are ineffective in preventing bicarbonate loss from samples.