Understanding Lab Tests for Hyperkalemia
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Hyperkalemia is a serious medical condition characterized by abnormally high levels of potassium in the blood. Since elevated potassium can cause dangerous heart rhythm problems and other complications, accurate diagnosis through blood testing is essential for proper treatment and monitoring.
Top Recommended Test
Potassium, Serum
This is the primary diagnostic test for hyperkalemia, directly measuring potassium levels in the blood serum. Elevated results confirm the diagnosis and help determine the severity of the condition, which can be caused by decreased kidney function, certain medications, or metabolic acidosis.
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Diagnosing Hyperkalemia
Blood tests are the primary method for diagnosing hyperkalemia. These tests directly measure potassium levels in the blood and can also help identify underlying causes such as kidney dysfunction, medication effects, or hormonal imbalances that may be contributing to the elevated potassium levels.
Other Relevant Tests
Comprehensive Metabolic Profile (includes eGFR)
This comprehensive panel provides a complete picture of metabolic function, including potassium levels and kidney function assessment through eGFR. Since hyperkalemia is often caused by kidney disease, hormone deficiencies, or medications, this test helps identify underlying causes while confirming the diagnosis.
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Kidney Function Profile
Since the kidneys are responsible for maintaining proper potassium balance in the body, this specialized profile is crucial for identifying kidney disease as a potential cause of hyperkalemia. Impaired kidney function is one of the most common reasons for elevated blood potassium levels.
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Electrolyte Panel
This panel measures all major electrolytes including potassium, providing a comprehensive view of electrolyte balance. It helps diagnose hyperkalemia while also assessing other electrolyte imbalances that may occur due to kidney dysfunction, certain medications, or dietary factors.
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Anion Gap Panel (Electrolyte Balance)
This test evaluates overall electrolyte balance and can help identify metabolic causes of hyperkalemia. It's particularly useful for detecting acid-base disorders and kidney-related issues that may contribute to abnormally high potassium levels in the blood.
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Potassium, RBC
This test measures potassium levels within red blood cells, providing additional insight into cellular potassium distribution. High RBC potassium levels can indicate hyperkalemia and help healthcare providers understand the condition's impact at the cellular level, especially when caused by kidney disease, medications, or adrenal gland disorders.
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Mineral Profile, RBCs
This comprehensive mineral analysis of red blood cells includes potassium and other essential minerals. It helps diagnose hyperkalemia by showing how excess potassium affects cellular mineral balance, which can result from kidney dysfunction, adrenal gland disorders, or excessive potassium intake.
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Tacrolimus, Highly Sensitive, LC/MS/MS
This specialized test measures tacrolimus levels in patients taking this immunosuppressive medication. Since tacrolimus can cause hyperkalemia as a side effect, monitoring drug levels helps determine if medication-induced high potassium is occurring, which could lead to dangerous heart rhythm problems.
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Post COVID-19 Expanded Panel
This comprehensive panel includes potassium testing along with other markers that may be affected after COVID-19 infection. Since hyperkalemia can occur due to kidney complications, diabetes, and certain medications used during or after COVID-19 treatment, this panel helps identify elevated potassium levels in post-COVID patients.
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Understanding Your Results
Normal serum potassium levels typically range from 3.5 to 5.0 mEq/L. Hyperkalemia is generally diagnosed when potassium levels exceed 5.5 mEq/L, with severe cases occurring above 6.0 mEq/L. Your healthcare provider will interpret your results in the context of your symptoms, medical history, and other test findings to determine the appropriate treatment approach.
Important Considerations
The information provided here is for educational purposes only and is not a substitute for professional medical advice. Hyperkalemia can be a medical emergency requiring immediate treatment. Always consult with a healthcare provider for proper diagnosis, interpretation of test results, and treatment recommendations.
