A 20-year-old woman complains of headache and discomfort in both sides of her jaw. Physical examination reveals enlarged parotid glands that are slightly tender on palpation. There is reddening of the orifice of Stensen's duct on intra oral examination; her temperature is 38.3degC, and the pulse rate is 80/min. Laboratory data show hemoglobin 14 g/dL; hematocrit 40%; WBC 11000/mL, with 33% segmented neutrophils, 7% monocytes, and 60% lymphocytes. Which of the following diagnostic tests will help to confirm the diagnosis of epidemic parotitis?

Acute and convalescent titres of specific IgG antibodies will confirm the diagnosis of mumps. A single test revealing a specific IgM antibody can also confirm the disease. Urine, saliva, and throat swabs will grow the mumps virus, but blood does not. Salivary amylase is elevated but is relatively nonspecific. Of course, a typical presentation during an epidemic probably does not require any confirmatory tests. Sporadic cases require more active confirmation. Other causes of parotitis requiring specific treatment include calculi, bacterial infections, and drugs. Tumors, sarcoid, TB, leukemia, Hodgkin's disease, Sjogren's syndrome, and lupus erythematosus can also cause parotid enlargement.