False-positive rubella virus infection is determined by combining clinical symptoms with a specific lgG affinity test. The main immune markers associated with rubella virus are lgG and lgM. lgG is a protective antibody produced by the body’s immune system, which can be seen during the reinfection and recovery phases of rubella virus infection, while lgM represents the acute phase of rubella virus infection. However, the IgM indicator is often false-positive, so the diagnosis can be aided by the patient’s clinical symptoms, such as the presence of prodromal symptoms such as fever, runny nose, sneezing, and muscle aches before the IgM positivity, as well as swollen lymph nodes in the neck and back of the ear that rapidly spreads to the trunk and limbs of the skin rash and so on. In addition, a rubella-specific lgG affinity test can be performed; the higher the lgG affinity, the more likely it is to indicate a past infection rather than a recent one. Regular follow-up and serial monitoring are required for best judgment. If the IgM is positive for a long period of time, it is more likely to be a true positive.