A person suspected of having metabolic alkalosis would have which of the following laboratory findings?

• A. CO2 content elevated and PCO2 elevated, pH decreased
• B. CO2 content decreased and pH elevated
• C. CO2 content decreased, PCO2 decreased and pH decreased
• D. CO2 content elevated and pH elevated

Answer: (D)

In metabolic alkalosis, the primary change is an increase in bicarbonate, which pushes the blood pH higher (alkalemia). This raises the total CO2 content measured in the lab because CO2 content reflects bicarbonate-related CO2 chemistry in the blood. The body compensates by retaining CO2 (hypoventilation), which would further elevate the CO2-related measurements, even though the main driver is the elevated bicarbonate. Therefore, the lab pattern of elevated CO2 content with an elevated pH fits metabolic alkalosis best. Other patterns would show acidemia or decreased CO2, which don’t align with an alkalotic state.