From the Guidelines
Pseudohyperkalemia should be suspected and managed by confirming the diagnosis through proper blood collection techniques and comparing serum potassium with plasma potassium levels, as it is a laboratory artifact that can lead to unnecessary and potentially harmful treatment. Pseudohyperkalemia is a condition where potassium levels are falsely elevated in the laboratory due to the release of potassium from cells during or after blood collection, often caused by hemolysis, extreme thrombocytosis, severe leukocytosis, or improper specimen handling 1. This condition can be distinguished from true hyperkalemia by comparing serum potassium levels with plasma potassium levels, which will be normal in pseudohyperkalemia.
To manage pseudohyperkalemia, it is essential to follow proper blood collection techniques, such as avoiding excessive tourniquet time, fist clenching, or vigorous tube shaking, using a large-bore needle, minimizing vacuum pressure during collection, and ensuring prompt processing of the sample 1. For patients with thrombocytosis or leukocytosis, collecting blood in heparin tubes rather than standard tubes and processing immediately can help prevent pseudohyperkalemia.
Some key points to consider in managing pseudohyperkalemia include:
- Confirming the diagnosis through proper blood collection techniques and comparison of serum and plasma potassium levels
- Avoiding unnecessary treatment with potassium-lowering therapies, which can lead to hypokalemia
- Identifying and addressing the underlying cause of pseudohyperkalemia, such as hemolysis or improper specimen handling
- Ensuring proper blood collection and processing techniques to prevent pseudohyperkalemia in high-risk patients, such as those with thrombocytosis or leukocytosis 1.
By following these steps and considering the potential causes and consequences of pseudohyperkalemia, clinicians can effectively manage this condition and prevent unnecessary treatment and potential harm to patients.
From the Research
Definition and Causes of Pseudohyperkalemia
- Pseudohyperkalemia is defined as a reported rise in serum potassium concentration along with a normal effective plasma potassium concentration 2.
- It can result from multiple factors, including excessive potassium leakage from cells of the forearm during blood collection, hemolysis, problems with sample transport, preanalysis or contamination, cell damage and metabolic changes, familial conditions that permit excessive potassium ion (K+) leak from erythrocytes after blood sampling, and leukocytosis or thrombocytosis 3.
- Patient factors like high platelet, leukocytes, or erythrocyte counts can also lead to pseudohyperkalemia 4.
Clinical Importance and Management
- Recognizing pseudohyperkalemia is crucial to avoid unnecessary and potentially dangerous treatment 2, 5.
- Differentiating true hyperkalemia from pseudohyperkalemia is very important in selected groups of patients to avoid unnecessary medications, higher level of care, and unnecessary procedures including dialysis 5.
- Timely identification of pseudohyperkalemia and differentiating it from true hyperkalemia becomes utmost important to base medical decisions on accurate potassium levels 6.
- To manage pseudohyperkalemia, it is essential to be aware of the preanalytical errors that may result in inaccurate potassium results, such as hemolysis, and to take corrective actions, including proper blood collection and sample processing techniques 4.
Diagnostic Considerations
- Pseudohyperkalemia can be suspected when there is a significant difference between serum and plasma potassium concentration, with serum values being higher 6.
- In patients with leukocytosis and thrombocytosis, pseudohyperkalemia may exist in the absence of electrocardiogram changes or other clinical manifestations of true hyperkalemia, leading to reevaluation of potassium values in serum, plasma, and whole blood to arrive at the true picture 6.
- A practical flow chart and a tabular overview of preanalytical errors, including possible underlying mechanisms, indicators for detection, suggestions for corrective actions, can be used to prevent and investigate potentially biased potassium results 4.