Diagnosis and Testing
Reviewed by: HU Medical Review Board | Last reviewed: September 2019
It has been estimated that roughly 1.1 million Americans are living with HIV, and about 15 percent are unaware of their status (have not yet been diagnosed).1,2 That’s about one out of every seven individuals with HIV. When an individual does not know their HIV status and is HIV-positive, they can unknowingly transmit the virus to others.
It can take a long time for serious, long-term symptoms related to HIV to arise. And the symptoms that can occur early on are often non-specific, and easy to mistake for another illness. This is why medical testing for HIV is so important and is the only way to know for sure whether or not you have the virus.
Who should get an HIV test?
Current recommendations from the Centers for Disease Control and Prevention in the United States encourage all individuals between the ages of 13 and 64 to have at least one HIV test.3-5 This HIV test can be incorporated into their normal care and can provide a baseline for their HIV status.
Some individuals may need to be tested more frequently for HIV or may be at increased risk of acquiring the virus. Aside from the CDC’s recommendation of a one-time test, individuals may need additional testing if they have one or more of the following risk factors:
- Have had vaginal or anal sex with someone who has or may have HIV
- Are a man who regularly has sex with other men
- Have ever exchanged sex for money, drugs, items, or basic living necessities
- Have had multiple sexual partners, especially if they’ve had multiple partners since their last HIV test
- Currently have, previously had, or have ever been treated for another sexually transmitted infection (STI), such as herpes, gonorrhea, chlamydia, or others
- Have, or previously have, used injection drugs and shared needles or other equipment to inject drugs with others (water, cotton, or other “works”)
- Have ever been diagnosed or treated for tuberculosis (TB) or hepatitis
- Have or previously have had sex with someone who has one or more of the previously listed risk factors4,5
Individuals who have one or more of these risk factors may need to be tested on a regular basis, such as once a year, for as long as the risk factors apply to them. Men who have sex with other men, especially unprotected sex with multiple partners, may benefit from more frequent testing, such as testing every three to six months.
This is because these are high-risk behaviors for transmitting HIV, and members of this group are often at an elevated risk of getting the virus. Additionally, since HIV can be transmitted from a pregnant woman to her child before, during, and after birth, it is recommended that all women receive an HIV test as part of their general prenatal workup once they find out they are pregnant.3-5
Symptoms at each stage of HIV
Primary HIV infection
An individual who is newly infected with HIV may show symptoms early on, and then have no symptoms for years after, depending on how quickly their HIV progresses. The symptoms that can occur early on are often non-specific and are easily mistaken for another illness like the flu or another short-term virus. For those who do experience signs of early-stage HIV infection, also called acute or primary HIV infection (lasting about two to four weeks), symptoms often include, but are not limited to:
- Fever (greater than 100.4ºF or 38ºC)
- Swollen lymph nodes (especially in the armpits and neck)
- Sore muscles or joints
- Sore throat
- Rash (especially across the neck, face, and upper chest)
- Dry cough
- Weight loss6-9
Clinical latency stage
The second stage of HIV (after acute or primary infection) is called the clinical latency stage. This period may also be referred to as chronic HIV infection. After initial infection, HIV replication eventually slows down within the body, although it never actually stops. Without treatment, this period of time can last anywhere from two to 15 years or more depending on a variety of factors.
With treatment, this period can last much longer. As time goes on, the HIV replication will slowly win out over the CD4 cells, leading to a significant decrease in CD4 count over time. CD4 cells are cells that are part of the immune system and help our bodies fight off infections and other foreign invaders. There are often no symptoms during this period.6-9
The most advanced stage of HIV is AIDS (acquired immunodeficiency virus). Eventually, the slowly replicating HIV in a person’s body will lead to a significant decrease in their CD4 cell count. A normal CD4 count in a healthy individual can be anywhere from 500-1,500 cells/microliter. When an individual has AIDS, their CD4 count is below 200 cells/microliter (also referred to as a CD4 count of 200).
Without CD4 cells, we are much more susceptible to illnesses, foreign invaders, and cancers, and can get infections that individuals with normally functioning immune systems don’t get. These are called opportunistic infections. Regardless of an individual’s CD4 count, they can be diagnosed with AIDS at any time if they have HIV and one or more AIDS-defining illnesses including invasive cervical cancer, Burkitt lymphoma, and many others.6-9
There are many locations and services an individual can use to get tested. A good first step is to visit your regular doctor or primary care provider. They can provide HIV testing, including proper interpretation of results and access to treatment if need be. Not all individuals needing HIV testing will feel comfortable seeing their primary care provider, and some may not have a regular provider at all. If this is the case, HIV testing is still readily available. Many community health centers or clinics offer testing, as well as local health departments, family planning clinics, substance abuse programs or treatment centers, VA health centers, and Planned Parenthood clinics.5,10
If you are unsure of where to start when it comes to HIV testing, you can also use national resources created by the CDC (Centers for Disease Control and Prevention) to find options near you. These include:
- Visiting gettested.cdc.gov
- Texting your zip code to 566948 (KNOW IT)
- Calling 1-800-CDC-INFO (1-800-232-4636)5
Different test types available
There are a variety of different tests available for HIV. Some of the most common tests include the following:
- Nucleic acid tests (NATs): NATs work by looking for HIV RNA in the blood. This is the virus’ genetic material, and shows that HIV is in your blood and replicating. NATs are generally only used when a person has had a recent exposure to HIV and is showing early-stage, flu-like symptoms. NATs are expensive and not typically used in routine screening.
- Antibody tests: As mentioned, when the body is infected with HIV, it begins to make antibodies against the virus. Antibody tests look for HIV-specific antibodies in the blood. Only an individual who is infected with HIV will have these. Someone who does not have HIV will not. Some antibody tests are rapid tests, meaning the results can come back in a matter of minutes.
- Antigen/antibody tests: In addition to antibodies, some tests may also look for virus-specific proteins in the blood. These virus-specific proteins are called antigens. Our immune system responds to, and fights off, foreign antigens when they enter our body. One HIV-specific antigen is called p24, which is a protein that is a part of HIV itself. Some tests may be able to detect this antigen sooner than HIV antibodies, and when tested together, may provide an earlier result.
- At-home testing kits: At-home kits look for HIV-specific antibodies in the blood. The only FDA-approved at-home testing kit currently available on the market is the OraQuick In-Home HIV test. The OraQuick requires a sample of oral fluid taken using a swab. The results come back in about 20 minutes. If an individual has tested positive for HIV using the at-home kit, follow-up testing in a healthcare setting will be required.5,11,12
After you test positive in a healthcare setting, your blood may need to be tested further to determine your viral load, or how much active virus is present in your body. This information helps your healthcare team guide and monitor your treatment.
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