Final answer:
The nurse would anticipate the prescription of calcitriol based on the patient's abnormal levels of calcium, phosphorus, and vitamin D.
Step-by-step explanation:
The nurse anticipates that the medication prescribed for a patient with chronic kidney disease (CKD) and abnormal levels of calcium, phosphorus, and vitamin D would be calcitriol. Calcitriol is the active form of vitamin D, which plays a crucial role in the regulation of calcium and phosphorus levels in the body. In this case, the patient's low vitamin D level (20 mg/mL) and high calcium level (13 mg/dL) suggest that additional calcitriol may be needed to help restore normal serum concentrations of calcium and phosphate.