The results of the HIV antibody test are usually available between 2 and 3 days after the blood is drawn, which is not a long time. However, the patient must take the HIV antibody test after the window period has passed, otherwise there is a possibility of getting a false negative result, which is not helpful to rule out HIV infection. If a patient wants to determine how long he or she has been in the window period, he or she should first consult with the local tertiary care hospital and the CDC about what kind of HIV antibody test is used. If the test is a third-generation test, the window period is about 6-8 weeks. If the test is a fourth-generation test, the window period can be shortened to about 42 days. Patients should always consult before making a judgment and when exactly to have the blood test.