Diagnosis of rabies requires the collection of multiple samples (e.g., saliva, skin, serum, cerebrospinal fluid) and multiple tests because of the limited sensitivity of a single test. For example, serum viral antibody titers may not be detected until late in the course of the disease, if ever. However, the sensitivity when combining multiple tests is close to 100%, depending on sample quality, timing of collection and diagnostic expertise. 1. Saliva: All saliva samples should be collected in small sterile containers and securely sealed. Laboratory tests include PCR for viral RNA and isolation of the virus by viral culture. 2. Skin biopsy: A piece of full-thickness skin (i.e., 5-6 mm in diameter) should be taken from the hairline at the back of the neck. The sample should include at least 10 hair follicles and the cutaneous nerve at the base of the follicle. The sample should be placed on a piece of sterile gauze moistened with sterile water (not immersed in diluent or transfer medium) and placed in an airtight container. Laboratory tests include PCR and immunofluorescent staining against viral antigens. 3. Serum and cerebrospinal fluid: At least 0.5mL of serum and cerebrospinal fluid should be collected for testing. If the patient has been vaccinated against rabies, another serum sample should be taken a few days later to see if the antibody titer is elevated. Laboratory tests for rabies antibodies include indirect immunofluorescence and virus neutralization tests.