The physician orders a lipid panel on Mary Smith to see if her cholesterol medication is working. The lipid panel includes ____.

The lipid panel specifically measures various components related to cholesterol and lipids in the blood, which are critical in assessing an individual's risk of heart disease and evaluating the effectiveness of cholesterol-lowering medications. The correct answer includes cholesterol levels, lipoproteins (such as LDL and HDL), and triglycerides. This panel provides essential information on both total cholesterol and its fractions, which helps physicians make informed decisions about a patient's treatment plan and lifestyle modifications.

The other options include tests that are not part of a lipid panel. Hemoglobin and hematocrit are measures of red blood cell levels and are used to evaluate anemia or polycythemia, while blood glucose and insulin tests are used to assess metabolic conditions like diabetes. The erythrocyte sedimentation rate is used to detect inflammation in the body and is unrelated to lipid levels. Thus, the lipid panel serves a unique and focused purpose that is accurately represented by the components listed in the correct answer.