Electrolytes
This section will cover:
- Electrolytes’ roles in the body
- How to measure and interpret electrolyte levels
- How to connect laboratory results to clinical diagnosis
Biochemical Theory and Pathways
- Electrolytes: Ions in solution, crucial for fluid balance, nerve/muscle function
- Key Electrolytes
- \(Na^+\), \(K^+\), \(Cl^-\), \(HCO_3^-\), \(Ca^{2+}\), \(Mg^{2+}\), \(P\), \(Fe\)
- Regulation
- Hormones: Aldosterone, ADH, PTH, Vitamin D
- Organs: Kidneys, parathyroid glands
- Transport Mechanisms
- Ion channels, pumps, binding proteins
Laboratory Test Procedures
- Common Methods
- Ion Selective Electrodes (ISE)
- Spectrophotometry
- Blood Gas Analysis
- Key Analytes Measured
- Electrolyte concentrations in serum, plasma, or whole blood
- Total Iron-Binding Capacity (TIBC)
- Important Considerations:
- Proper specimen collection and handling
- Reagent and calibration controls
Calculations
- Osmolality
- Formula: \(2[Na^+] + \left( \frac {[Glucose (mg/dL)]} {18} \right) + \left( \frac {[BUN (mg/dL)]} {2.8} \right)\)
- Assesses hydration, presence of toxins
- Anion Gap
- Formula: (\(Na^+\) + \(K^+\)) - (\(Cl^-\) + \(HCO_3^-\))
- Identifies causes of metabolic acidosis