Electrolyte Abnormalities, Life Threatening

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Suspected electrolyte abnormality in patient (eg, unconscious or confused patient, patient on 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 sodium, potassium chloride, bicarbonate, blood urea nitrogen (BUN), creatinine, glucose, and calcium
  • Magnesium
  • Albumin
    • Order serum test concurrently if calcium abnormality suspected
    • If hypocalcemia suspected – also order magnesium
  • For further evaluation, refer to hypocalcemia

Differential Diagnosis

  • Refer to individual topics in Clinical Background section under causes

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).

  • Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

    Comprehensive Metabolic Panel 0020408
    Method: Quantitative Ion-Selective Electrode/Quantitative Enzymatic/Quantitative Spectrophotometry

    Magnesium, Plasma or Serum 0020039
    Method: Quantitative Spectrophotometry


    Verbalis JG, Goldsmith SR, Greenberg A, Korzelius C, Schrier RW, Sterns RH, Thompson CJ. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am J Med. 2013; 126(10 Suppl 1): S1-42. PubMed

    General References

    Assadi F. Hypomagnesemia: an evidence-based approach to clinical cases. Iran J Kidney Dis. 2010; 4(1): 13-9. PubMed

    Bosworth M, Mouw D, Skolnik DC, Hoekzema G. Clinical inquiries: what is the best workup for hypocalcemia? J Fam Pract. 2008; 57(10): 677-9. PubMed

    Braun MM, Barstow CH, Pyzocha NJ. Diagnosis and management of sodium disorders: hyponatremia and hypernatremia. Am Fam Physician. 2015; 91(5): 299-307. PubMed

    Cohen DM, Ellison DH. Evaluating hyponatremia. JAMA. 2015; 313(12): 1260-1. PubMed

    Cooper MS, Gittoes NJ. Diagnosis and management of hypocalcaemia. BMJ. 2008; 336(7656): 1298-302. PubMed

    Goff DA, Higinio V. Hypernatremia. Pediatr Rev. 2009; 30(10): 412-3; discussion 413. PubMed

    Henry DA. In The Clinic: Hyponatremia. Ann Intern Med. 2015; 163(3): ITC1-19. PubMed

    Musso CG. Magnesium metabolism in health and disease. Int Urol Nephrol. 2009; 41(2): 357-62. PubMed

    Nyirenda MJ, Tang JI, Padfield PL, Seckl JR. Hyperkalaemia. BMJ. 2009; 339: b4114. PubMed

    Palmer BF, Clegg DJ. Electrolyte and Acid-Base Disturbances in Patients with Diabetes Mellitus. N Engl J Med. 2015; 373(6): 548-59. PubMed

    Ranadive SA, Rosenthal SM. Pediatric disorders of water balance. Endocrinol Metab Clin North Am. 2009; 38(4): 663-72. PubMed

    Sterns RH. Disorders of plasma sodium--causes, consequences, and correction. N Engl J Med. 2015; 372(1): 55-65. PubMed

    Viera AJ, Wouk N. Potassium Disorders: Hypokalemia and Hyperkalemia Am Fam Physician. 2015; 92(6): 487-95. PubMed

    Medical Reviewers

    Last Update: September 2017