SIGNS / SYMPTOMS
Pseudohyperkalemia is a falsely elevated potassium concentration due to release of potassium from blood cells during in vitro coagulation. Hematologic disorders (e.g., thrombocytosis, polycythemia vera, extreme leukocytosis [as in leukemia], hereditary spherocytosis) may predispose to pseudohyperkalemia.[2]Rafique Z, Peacock F, Armstead T, et al. Hyperkalemia management in the emergency department: an expert panel consensus. J Am Coll Emerg Physicians Open. 2021 Oct;2(5):e12572.
https://www.doi.org/10.1002/emp2.12572
http://www.ncbi.nlm.nih.gov/pubmed/34632453?tool=bestpractice.com
Pseudohyperkalemia may also be caused by errors in sample collection and/or storage, such as prolonged transit time from taking the sample to laboratory analysis, poor storage conditions, and mechanical trauma during venipuncture.[1]Alfonzo A, Harrison A, Baines R, et al; UK Kidney Association (formerly the Renal Association). Clinical practice guidelines: treatment of acute hyperkalaemia in adults. June 2020 [internet publication].
https://ukkidney.org/sites/renal.org/files/RENAL%20ASSOCIATION%20HYPERKALAEMIA%20GUIDELINE%20-%20JULY%202022%20V2_0.pdf
[2]Rafique Z, Peacock F, Armstead T, et al. Hyperkalemia management in the emergency department: an expert panel consensus. J Am Coll Emerg Physicians Open. 2021 Oct;2(5):e12572.
https://www.doi.org/10.1002/emp2.12572
http://www.ncbi.nlm.nih.gov/pubmed/34632453?tool=bestpractice.com
Consider pseudohyperkalemia if the patient has normal renal function, normal ECG, and/or history of a hematologic disorder.[1]Alfonzo A, Harrison A, Baines R, et al; UK Kidney Association (formerly the Renal Association). Clinical practice guidelines: treatment of acute hyperkalaemia in adults. June 2020 [internet publication].
https://ukkidney.org/sites/renal.org/files/RENAL%20ASSOCIATION%20HYPERKALAEMIA%20GUIDELINE%20-%20JULY%202022%20V2_0.pdf
INVESTIGATIONS
Repeated measurements of serum potassium will be normal.[2]Rafique Z, Peacock F, Armstead T, et al. Hyperkalemia management in the emergency department: an expert panel consensus. J Am Coll Emerg Physicians Open. 2021 Oct;2(5):e12572.
https://www.doi.org/10.1002/emp2.12572
http://www.ncbi.nlm.nih.gov/pubmed/34632453?tool=bestpractice.com
In practice, if there was mechanical trauma during venipuncture, the serum will have a reddish tint and the laboratory will usually report the result as hemolyzed.