Podcast
Questions and Answers
What is one potential cause of artifactual hyperkalemia when blood is taken from patients with thrombocytosis?
What is one potential cause of artifactual hyperkalemia when blood is taken from patients with thrombocytosis?
What practice can help prevent increased potassium levels due to thrombocytosis during blood collection?
What practice can help prevent increased potassium levels due to thrombocytosis during blood collection?
How does clenching the fist excessively before venipuncture affect potassium levels?
How does clenching the fist excessively before venipuncture affect potassium levels?
What is the recommended temperature to store whole blood samples for K+ determinations?
What is the recommended temperature to store whole blood samples for K+ determinations?
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What can result from hemolysis of blood samples after collection?
What can result from hemolysis of blood samples after collection?
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What approximate increase in potassium is associated with slight hemolysis of about 50 mg/dL of hemoglobin?
What approximate increase in potassium is associated with slight hemolysis of about 50 mg/dL of hemoglobin?
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What is the maximum estimated increase in potassium levels due to gross hemolysis of more than 500 mg/dL of hemoglobin?
What is the maximum estimated increase in potassium levels due to gross hemolysis of more than 500 mg/dL of hemoglobin?
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Which of the following practices should be avoided to prevent artifactual hyperkalemia during sample collection?
Which of the following practices should be avoided to prevent artifactual hyperkalemia during sample collection?
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Flashcards
How does coagulation affect potassium?
How does coagulation affect potassium?
The process of blood clotting releases potassium from platelets, leading to higher serum potassium levels compared to plasma potassium levels.
How does platelet count influence potassium?
How does platelet count influence potassium?
High platelet count (thrombocytosis) can further elevate serum potassium levels due to increased potassium release during clotting.
What can cause artifactual hyperkalemia during blood collection?
What can cause artifactual hyperkalemia during blood collection?
Leaving a tourniquet on for too long during blood collection or excessive forearm squeezing can cause cells to release potassium into the plasma.
How do you avoid potassium release due to clotting?
How do you avoid potassium release due to clotting?
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Why should blood samples for potassium analysis be stored at room temperature?
Why should blood samples for potassium analysis be stored at room temperature?
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How does hemolysis affect potassium?
How does hemolysis affect potassium?
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What is the effect of slight hemolysis on potassium levels?
What is the effect of slight hemolysis on potassium levels?
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What is the effect of gross hemolysis on potassium levels?
What is the effect of gross hemolysis on potassium levels?
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Study Notes
Sample Collection for Potassium (K+) Analysis
- Proper sample collection crucial for accurate K+ analysis. Artifactual hyperkalemia (falsely high K+) has many causes.
- Coagulation and Platelets: Serum K+ may be 0.1–0.7 mmol/L higher than plasma K+ due to K+ release from platelets. High platelet counts (thrombocytosis) further elevate serum K+.
- Tourniquets and Muscle Contraction: Prolonged tourniquet use, muscle clenching, or exercise before venipuncture release K+ from cells into the plasma.
- Preventing Artifactual Hyperkalemia: Use heparinized tubes to prevent clotting, and handle patients gently before blood draw.
- Storage and Analysis: Storing blood on ice releases K+ from cells, so room temperature storage is preferred. Analyze samples promptly or centrifuge to separate cells before analyzing.
- Hemolysis: Hemolysis (rupturing of red blood cells) after blood draw is the most common cause of artifactual hyperkalemia. Slight hemolysis (≈50 mg/dL hemoglobin) increases K+ by about 3%. Gross hemolysis (>500 mg/dL hemoglobin) raises K+ by up to 30%.
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Description
Explore the critical procedures for proper sample collection in potassium (K+) analysis. Understand the potential impacts of artifacts such as hyperkalemia, methods for preventing them, and best practices for sample handling and storage.
