From the Guidelines
Pseudo-hyperkalemia should be suspected and investigated when a patient's potassium levels are elevated without corresponding clinical symptoms, and measurement should be repeated with proper blood sampling techniques to rule out laboratory artifacts, as stated in the expert consensus document on hyperkalaemia management 1. When evaluating a patient with suspected pseudo-hyperkalemia, it is essential to consider the potential causes of this laboratory artifact, including hemolysis, thrombocytosis, or leukocytosis.
- Key factors to consider in the diagnosis of pseudo-hyperkalemia include:
- Comparison of serum and plasma potassium levels to identify significant differences
- Proper blood collection techniques to prevent hemolysis or other artifacts
- Use of lithium heparin tubes for blood collection and prompt transportation to the laboratory
- The expert consensus document on hyperkalaemia management highlights the importance of recognizing pseudo-hyperkalemia to avoid unnecessary treatment and potential harm to patients 1. In clinical practice, pseudo-hyperkalemia can be prevented by following proper blood collection and handling procedures, and clinicians should be aware of the potential for laboratory artifacts when interpreting potassium levels, as emphasized in the European Heart Journal study 1.
- The study also notes that hyperkalaemia can be classified as mild, moderate, or severe, and that the risk of arrhythmic emergencies and sudden death varies widely among patients, making accurate diagnosis and management crucial 1. Proper diagnosis and management of pseudo-hyperkalemia are critical to prevent unnecessary treatment and potential harm to patients, and clinicians should prioritize accurate laboratory results and careful patient evaluation, as recommended by the expert consensus document 1.
From the Research
Definition and Causes of Pseudo Hyperkalemia
- Pseudo hyperkalemia is defined as an artificial rise in serum potassium (Sk) that does not reflect the actual in vivo serum potassium levels 2.
- It can result from multiple factors, including:
- Excessive potassium leakage from cells of the forearm during blood collection due to release from exercising the muscle during fist clenching, while washout is prevented by tourniquet application 2.
- Hemolysis, problems with sample transport, preanalysis or contamination, cell damage and metabolic changes 2, 3.
- Familial conditions that permit excessive potassium ion (K+) leak from erythrocytes after blood sampling 2.
- Leukocytosis or thrombocytosis 2, 4.
Clinical Importance and Implications
- Differentiating true hyperkalemia from pseudo hyperkalemia is crucial to avoid unnecessary medications, higher level of care, and unnecessary procedures including dialysis 5.
- Pseudo hyperkalemia can lead to misdiagnosis and inappropriate patient management, highlighting the need for immediate recognition and appropriate interpretation 3.
- In patients with leukocytosis and thrombocytosis, pseudo hyperkalemia may exist in the absence of electrocardiogram changes or other clinical manifestations of true hyperkalemia 4.
Diagnosis and Prevention
- To diagnose pseudo hyperkalemia, it is essential to compare serum and plasma potassium concentrations, with a difference of more than 0.4 meq/L indicating pseudo hyperkalemia 4.
- Preventive measures include proper blood collection techniques, such as avoiding fist clenching and tourniquet application, and ensuring timely sample processing and analysis 2, 3.
- An algorithm for investigation of pseudo hyperkalemia and preventive measures should be established and implemented in the clinical laboratory to improve patient care 3.