<prompt> The nurse is assigned to care for a client with cytomegalovirus retinitis and acquired immunodeficiency syndrome who is receiving foscarnet Foscavir. The nurse carefully monitors which of the following laboratory test during the treatment with this medication, except?Serum creatinine.Serum calcium.Serum magnesium.Serum sodium.  <response>: Renal impairment is the major toxicity involve in Foscarnet Foscavir; This medicine also may cause decreased levels of calcium, magnesium, phosphorous, and potassium. 