A woman visits a health center requesting oral contraceptives. Which laboratory test is most important for the nurse to assess before the patient begins oral contraceptive therapy?

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: This is incorrect because constipation is not a common or serious adverse effect of antihistamines. However, the patient should increase their fluid and fiber intake and exercise regularly to prevent constipation.

Choice B reason: This is incorrect because abdominal cramps are not a common or serious adverse effect of antihistamines. However, the patient should avoid spicy or fatty foods and take the antihistamine with food or milk to prevent stomach irritation.

Choice C reason: This is correct because drowsiness is one of the most common and bothersome adverse effects of antihistamines. The patient should avoid driving or operating machinery if they experience drowsiness and take the antihistamine at bedtime.

Choice D reason: This is incorrect because decreased libido is not a common or serious adverse effect of antihistamines. However, the patient should inform their provider if they experience any sexual dysfunction or mood changes while taking the antihistamine.