A nurse is reviewing the medication list for a client who has a new diagnosis of type 2 diabetes mellitus. The nurse should recognize which of the following medications can cause glucose intolerance?

Choice A reason: This is correct because hemoglobin A1C level reflects the average blood glucose level over the past 2 to 3 months. It is a reliable indicator of the patient's glycemic control and adherence to the antidiabetic therapy. The goal for most patients with type 2 diabetes is to keep the hemoglobin A1C level below 7%.

Choice B reason: This is incorrect because serum insulin level is not a good measure of the patient's adherence to the antidiabetic therapy, as it may vary depending on the type, dose, and timing of the insulin or oral antidiabetic agents. Serum insulin level may also be affected by other factors, such as stress, infection, or exercise.

Choice C reason: This is incorrect because fingerstick fasting blood glucose level only reflects the blood glucose level at a single point in time. It does not provide information about the patient's long-term glycemic control or adherence to the antidiabetic therapy. Fingerstick fasting blood glucose level may also be influenced by the patient's diet, activity, or medication intake before the test.

Choice D reason: This is incorrect because hemoglobin level is not related to the patient's adherence to the antidiabetic therapy, as it measures the amount of oxygen-carrying protein in the red blood cells. Hemoglobin level may be affected by conditions such as anemia, dehydration, or blood loss.

Choice A reason: Vaginal cultures are not necessary for oral contraceptive therapy. They are used to diagnose infections such as bacterial vaginosis, yeast infection, or sexually transmitted diseases.

Choice B reason: Complete blood count is not essential for oral contraceptive therapy. It is used to measure the number and types of blood cells, such as red blood cells, white blood cells, and platelets.

Choice C reason: Serum potassium level is the most important laboratory test for oral contraceptive therapy. This is because some oral contraceptives can increase the risk of hyperkalemia, which is a high level of potassium in the blood. Hyperkalemia can cause serious complications such as cardiac arrhythmias, muscle weakness, and paralysis.

Choice D reason: Pregnancy test is not a laboratory test, but a urine test. It is important to rule out pregnancy before starting oral contraceptive therapy, but it is not the most important test for the nurse to assess.