Since the advent of HIV, great progress has been made in education, awareness, testing technology and access to care—yet HIV is still stigmatized and continues to spread. As other articles in our HIV Testing series have mentioned, a large number of people are unaware that they have HIV. The CDC (Centers for Disease Control and Prevention) estimates that one out of four HIV-positive Americans are unaware of their status. Those numbers are even higher outside of the United States: the World Health Organization estimates that 80 percent of people with HIV in developing countries are unaware they have it. With so many people unaware of their HIV status, increasing testing is critical to prevent new infections and help HIV-positive people lead healthy lives.

There are a variety of ways to get tested. You can go to your doctor's office, go to a local testing site (such as a public health clinic), or use an in-home test. At the doctor's office or clinic, they may offer the standard blood test that requires blood drawn from a vein (enzyme immunoassay or Elisa), or they may offer a rapid test (which uses saliva or blood from a fingerprick). Rapid HIV antibody tests have developed over the past decade and provide results in approximately 5-30 minutes (as opposed to 2 weeks with Elisa tests). Same-day results from rapid tests increase their effectiveness, as people don't always return to get their results after 2 weeks. Rapid tests have also expanded access to testing, since they don't require specialized equipment and extensive lab work. A positive result from an Elisa or rapid test should be confirmed with a Western Blot test.

There is only one at-home test that has been approved by the Federal Drug Administration (FDA): the Home Access HIV-1 Test System, which can be found at most drugstores. This collection kit allows a consumer to prick their finger and send the blood sample to a laboratory. After a specified amount of time, the consumer calls the lab with their identification number to receive the results over the phone. This method is controversial because some experts believe that test counseling is better in person.

The CDC revised its recommendations last fall to advocate that all patients in all health-care settings aged 13-64 years get routine screening for HIV infection. Their rationale for "opt-out" screening:

People who are infected with HIV but not aware of it are not able to take advantage of the therapies that can keep them healthy and extend their lives, nor do they have the knowledge to protect their sex or drug-use partners from becoming infected. Knowing whether one is positive or negative for HIV confers great benefits in healthy decision making.

The CDC also recommends universal HIV screening for pregnant women early in their pregnancy. This enables HIV-positive women and infants to benefit from medication and other important health advances.

There are many complex and different reasons why people don't get tested. But as testing technology continues to improve, testing sites increase, policies change and society addresses the stigma and discrimination associated with HIV, those reasons will stand in the way less and less. Knowledge is power.