Deceptive potassium and magnesium measurements

Area of Science:

• Clinical Chemistry
• Electrolyte Balance
• Diagnostic Testing

Background:

• Potassium and magnesium are vital intracellular cations with only ~1% circulating in extracellular fluids like blood.
• Blood levels of these electrolytes are frequently used to estimate total body content.
• Inaccurate measurements can lead to significant clinical consequences.

Purpose of the Study:

• To highlight and discuss the often-overlooked pitfalls in potassium and magnesium blood measurements.
• To provide methods for identifying and correcting these measurement errors.
• To enhance the clinical interpretation of electrolyte test results.

Main Methods:

• Review and analysis of common laboratory procedures for potassium and magnesium.
• Identification of pre-analytical and analytical factors affecting measurement accuracy.
• Discussion of clinical case scenarios illustrating interpretation challenges.

Main Results:

• Several less-appreciated technical and interpretative pitfalls associated with potassium and magnesium assays were identified.
• Specific recommendations for improving the reliability of these measurements were proposed.
• The potential for misdiagnosis due to flawed electrolyte testing was emphasized.

Conclusions:

• Awareness of measurement limitations is essential for accurate potassium and magnesium assessment.
• Improved laboratory practices and clinical interpretation can prevent diagnostic errors.
• Addressing these pitfalls can reduce unnecessary investigations and healthcare costs.