As the prevalence of mumps is low, routine serology testing for anti-mumps IgM antibodies may yield false positive results. Patients having an illness with acute onset of unilateral or bilateral tender, self-limited, swelling of the parotid or other salivary gland, lasting 2 or more days, and without other apparent cause should be discussed with public health officials. Appropriate testing in this situation would consist of Mumps PCR, performed on oral/buccal swabs submitted in viral transport media. Testing is performed only with prior approval by the Michigan Department of Health and Human Services. Pre-approval arrangements must be made through Infection Prevention and Epidemiology at 734-936-6355 or page 30032