Hyperkalemia laboratory findings

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Priyamvada Singh, M.B.B.S. [2], Aditya Ganti M.B.B.S. [3]

Overview

In a patient who does not have a risk for hyperkalemia, repeating the blood test is indicated before taking any actions unless changes are present on electrocardiography

Laboratory Findings

The first step in diagnosing hyperkalemia is to exclude pseudohyperkalemia by repeating the blood test.^[1]

Grade	Potassium level
Mild	5-6.0mEq/L
Moderate	6.1-7.2mEq/L
Severe	>7.2mEq/L

Initial tests

Complete blood count (CBC)^[2]
Metabolic profile .^[3]
Urine potassium, sodium, and osmolality ^[4]

Aldosterone

Hyperkalemia

Exclude psuedohyperkalemia by repeating the blood test

Acute rise in potassium

Persistent hyperkalemia

Increase release of K+ from cells
Trauma,radiation therapy, DKA, metabolic acidosis

Decreased urinary excreation of K+
rule out aldosterone deficency
24 hr urine K+ excreation

Cause specific

Blood glucose In patients with history of diabetes mellitus
Digoxin level
Arterial or venous blood gas (acidosis)
Urinalysis (renal insufficiency)
Serum cortisol and aldosterone levels (mineralocorticoid deficiency)
Serum uric acid and phosphorus assays (tumor lysis syndrome)
Serum creatinine phosphokinase (CPK) and calcium measurements and urine myoglobin test (crush injury or rhabdomyolysis)

Psudeohyperkalemia

Defined as the release of potassium from cells after their breakdown. Most commonly seen during blood collection, so it’s required to repeat blood test in patients with a transient rise in potassium without any risk factors.
Other causes include
- Clotting increases release of potassium from platelets
- In patients with the history of leukemia where the WBC count is >120,000/microL the potassium is raised to cell fragility
- Hereditary (familial) forms of pseudohyperkalemia

References

↑ Lehnhardt A, Kemper MJ (2011). “Pathogenesis, diagnosis and management of hyperkalemia”. Pediatr Nephrol. 26 (3): 377–84. doi:10.1007/s00467-010-1699-3. PMC 3061004. PMID 21181208.
↑ Ingelfinger JR (2015). “A new era for the treatment of hyperkalemia?”. N Engl J Med. 372 (3): 275–7. doi:10.1056/NEJMe1414112. PMID 25415806.
↑ Kogika MM, de Morais HA (2017). “A Quick Reference on Hyperkalemia”. Vet. Clin. North Am. Small Anim. Pract. 47 (2): 223–228. doi:10.1016/j.cvsm.2016.10.009. PMID 27939860.
↑ Conte G, Dal Canton A, Imperatore P, De Nicola L, Gigliotti G, Pisanti N; et al. (1990). “Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure”. Kidney Int. 38 (2): 301–7. PMID 2402122.

Template:WH Template:WS

[pmid21181208-1] Lehnhardt A, Kemper MJ (2011). “Pathogenesis, diagnosis and management of hyperkalemia”. Pediatr Nephrol. 26 (3): 377–84. doi:10.1007/s00467-010-1699-3. PMC 3061004. PMID 21181208.

[pmid25415806-2] Ingelfinger JR (2015). “A new era for the treatment of hyperkalemia?”. N Engl J Med. 372 (3): 275–7. doi:10.1056/NEJMe1414112. PMID 25415806.

[pmid27939860-3] Kogika MM, de Morais HA (2017). “A Quick Reference on Hyperkalemia”. Vet. Clin. North Am. Small Anim. Pract. 47 (2): 223–228. doi:10.1016/j.cvsm.2016.10.009. PMID 27939860.

[pmid2402122-4] Conte G, Dal Canton A, Imperatore P, De Nicola L, Gigliotti G, Pisanti N; et al. (1990). “Acute increase in plasma osmolality as a cause of hyperkalemia in patients with renal failure”. Kidney Int. 38 (2): 301–7. PMID 2402122.

[1]

[2]

[3]

[4]