The alteration of serum potassium level during sample transit

Area of Science:

• Clinical Biochemistry
• Laboratory Medicine
• Analytical Chemistry

Background:

• Accurate blood test results are crucial for patient diagnosis and treatment.
• Pre-analytical variables, such as sample handling time, can impact laboratory test outcomes.
• Potassium levels are vital electrolytes with narrow therapeutic ranges.

Purpose of the Study:

• To investigate the effect of delayed blood sample processing on serum potassium levels.
• To determine the time frame at which potassium levels become significantly altered.
• To assess the clinical significance of potassium level changes due to sample delay.

Main Methods:

• Blood samples were collected via venepuncture.
• Samples were processed at varying time intervals post-collection (e.g., immediate, 1 hour, 3 hours).
• Serum potassium concentrations were measured using standard laboratory analyzers.

Main Results:

• A delay of three hours between venepuncture and blood processing led to unpredictable increases in potassium levels.
• The magnitude of potassium elevation varied between samples.
• These potassium level changes were deemed potentially clinically significant.

Conclusions:

• Prompt processing of blood samples is essential to ensure accurate potassium measurements.
• Delays exceeding three hours can introduce pre-analytical errors affecting potassium results.
• Clinical decisions based on potassium levels should consider potential pre-analytical sample handling delays.