Life-Threatening Electrolyte Abnormalities

Electrolyte abnormalities are common in both outpatient and inpatient settings. Uncorrected electrolyte abnormalities may have life-threatening consequences. Important electrolytes include calcium (Ca), potassium (K), sodium (Na), and magnesium (Mg).


Indications for Testing

Suspected electrolyte abnormality (eg, patient with loss of consciousness, or patient receiving diuretic therapy)

Laboratory Testing

  • Evaluate whether elevation or decrease is real
    • Hyperkalemia – evaluate for hemolysis in sample
    • Hyponatremia – evaluate for presence of hyperglycemia or hyperlipidemia
  • Initial screen – panel should include Na, potassium chloride, bicarbonate, blood urea nitrogen (BUN), creatinine, glucose, and Ca
  • Mg
  • Albumin
    • Order serum test concurrently if calcium abnormality suspected
    • If hypocalcemia suspected – also order Mg
  • For further evaluation, refer to hypocalcemia

Differential Diagnosis

Refer to individual topics in Background.



ARUP Lab Tests

Evaluate electrolyte abnormalities and underlying hepatic or renal dysfunction

Panel includes albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, bilirubin, Ca, carbon dioxide, creatinine, chloride, glucose, K, protein, Na, and urea nitrogen

Evaluate Mg concentrations in blood

Related Tests

Evaluate for kidney dysfunction in patients with known risk factors (eg, hypertension, diabetes, obesity, family history of kidney disease)

Panel includes Ca, carbon dioxide, chloride, creatinine, glucose, K, Na, and urea nitrogen

Panel includes anion gap carbon dioxide, chloride, K, and Na

Panel includes Na, K, chloride, and creatinine

Diagnose and manage diabetes mellitus and other carbohydrate metabolism disorders

Use to correct for hypoalbuminemia on serum Ca level

Determine Ca concentrations

Asses Ca status

Use for classification of Na disorders and evaluation of unmeasured ions

May be useful in assessment of tissue stores

For routine assessment of Mg deficiency, plasma or serum Mg is preferred

Medical Experts



Jonathan R. Genzen, MD, PhD
Associate Professor of Clinical Pathology, University of Utah
Chief Operations Officer, Medical Director of Automated Core Laboratory, ARUP Laboratories


Christopher M. Lehman, MD
Associate Professor of Clinical Pathology, University of Utah
Medical Director, University of Utah Health Hospital Clinical Laboratory, ARUP Laboratories


Additional Resources