Given the following serum electrolyte data, what is the anion gap: Na = 132 mmol/L, Cl = 90 mmol/L, HCO3- = 22 mmol/L?

To calculate the anion gap, we use the formula:

Anion Gap = (Na+) - (Cl- + HCO3-)

In this case, the serum sodium (Na+) is 132 mmol/L, the serum chloride (Cl-) is 90 mmol/L, and the serum bicarbonate (HCO3-) is 22 mmol/L. Plugging these values into the formula gives:

Anion Gap = 132 - (90 + 22)

Anion Gap = 132 - 112

Anion Gap = 20 mmol/L

This result indicates an anion gap of 20 mmol/L, which aligns with the correct choice. The anion gap is a useful measure in clinical chemistry, commonly used to help identify metabolic acidosis and other electrolyte imbalances. By calculating the anion gap, healthcare professionals can gather critical information about an individual's metabolic state and potential underlying health issues.