More than one million Americans are living with HIV infection, and approximately one in five don't know it. CDC recommends that everyone between the ages of 13 and 64 be tested for HIV at least once in their lifetime, and those at increased risk—such as gay and bisexual men, injection drug users, or persons with multiple sexual partners—should be tested at least annually. Testing is an essential first step to link persons with HIV infection to medical care and ongoing support to improve their health and help them maintain safer behaviors.CDC also recommends that pregnant women get tested early in their pregnancy so steps can be taken that will prevent transmission of HIV to their babies.