Rabies virus can be detected by rabies virus antibodies. Neutralizing antibodies can appear right after rabies vaccination, and if the vaccine is effective, the neutralizing antibody level will be above 0.5 IU/mL. However, if a person has a rabies attack, a large amount of rabies virus neutralizing antibodies can be detected in the blood 7 or 8 days after the onset of clinical symptoms, and the concentration of this neutralizing antibody is much higher than the concentration after rabies vaccination, so this can be used as a rabies laboratory test. However, because it can appear in the bloodstream only a few days after the onset of clinical symptoms, it cannot be used as a relevant test during the incubation period. There are no laboratory tests that can be used to determine that a patient is infected with the rabies virus during the incubation period of rabies, which is before the onset of clinical symptoms. Because the rabies virus is present in the nerves and not in the circulation at this time, it cannot be detected by blood sampling. It is only after the onset of rabies or even death that more means of testing are available, usually by taking the brain tissue of the deceased and seeing if there are any endogeneous vesicles inside.