From the Research
Dehydration significantly alters a Basic Metabolic Panel (BMP) by causing several characteristic changes, including elevated blood urea nitrogen (BUN) and creatinine levels, electrolyte abnormalities, and changes in bicarbonate and glucose levels, as seen in studies such as 1 and 2. When a patient is dehydrated, the BMP typically shows elevated BUN and creatinine levels, reflecting decreased kidney perfusion and reduced glomerular filtration rate. The BUN-to-creatinine ratio often increases above the normal 10:1 to 15:1 or higher.
- Electrolyte abnormalities are common, including hypernatremia (elevated sodium) due to free water loss exceeding sodium loss.
- Potassium levels may be elevated (hyperkalemia) or decreased (hypokalemia) depending on the cause and severity of dehydration.
- Bicarbonate levels might be decreased in cases of metabolic acidosis from severe dehydration, while glucose can be elevated due to stress hormone release.
- Chloride levels typically follow sodium changes. These alterations occur because dehydration reduces blood volume, concentrates blood components, and impairs kidney function, leading to retention of waste products and disruption of electrolyte balance. Clinicians should consider the patient's hydration status when interpreting BMP results, as rehydration often normalizes these laboratory abnormalities, as suggested by studies such as 3, 4, and 5. In clinical practice, it is essential to prioritize the patient's hydration status and consider the potential effects of dehydration on BMP results to provide accurate diagnosis and treatment, as supported by the most recent and highest quality study 1.