Which of the following tests evaluates carbon dioxide levels in the blood?

The test that specifically evaluates carbon dioxide levels in the blood is the Carbon Dioxide (CO2) test. This test directly measures the amount of carbon dioxide present in the blood, which is important for assessing a patient's acid-base balance and assessing respiratory and metabolic functions.

The CO2 levels can indicate how well the lungs are working to remove carbon dioxide from the body and whether there are any issues with the metabolic processes in the body that may be leading to an accumulation of carbon dioxide. Elevated or decreased levels can provide critical information about a patient’s respiratory and overall health.

While other tests listed may provide useful information about other substances or functions, they do not directly assess carbon dioxide levels. For instance, the BMP (Basic Metabolic Panel) does include a measurement of bicarbonate, which is related to carbon dioxide, but it is not a direct measurement of CO2 itself. Creatinine is a marker for kidney function, and Brain Natriuretic Peptide is associated with heart failure. Therefore, the CO2 test is the specific assay for measuring carbon dioxide in the blood.