Definition and Overview

HIV screening tests are performed to determine if the patient’s body is hosting the human immunodeficiency virus, or HIV, which is responsible for AIDS (or acquired immunodeficiency syndrome). The patient’s urine, saliva, or blood will be used for testing.

Over the years, HIV screening tests have developed to be more sophisticated. Testing procedure can measure various factors, such as the patient’s RNA, as well as the presence of antigens and antibodies. However, it is important to note that HIV screening tests do not accurately diagnose AIDS—it is mostly concerned with diagnosing the presence of the human immunodeficiency virus, which can cause AIDS, but not in every single patient.

Aside from diagnosis, HIV screening procedures can also be used to monitor the progress of the virus, which could be instrumental in the treatment and management of the disease.

The HIV screening procedure offers patients with several benefits; the first and most important one being the relief of anxiety over one’s unknown status. These tests can also be used to provide the patient and his doctor with a baseline, which could be highly useful in providing the patient with the most appropriate overall healthcare. Patients who tested negative can access information to protect themselves and adapt behaviours that can protect them from future infection. On the other hand, patients who tested positive will also gain access not just to information but also to care, support, counselling, and treatment to manage their symptoms. It is also important for HIV-positive patients to learn about the ways to prevent transmission and possible re-exposure in the future.

Who Should Undergo and Expected Results

Everyone can undergo HIV screening procedure, but it is highly recommended for people who are at risk. People who meet the following conditions are the best candidates:

  • Has had sexual contact with multiple partners
  • Has had unprotected sex with a person who has HIV or could be positive for the virus
  • Has injected steroids or drugs, or who has shared needles or other such equipment with another person during the use of said drugs
  • Has a history of sexually transmitted disease, such as herpes and hepatitis
  • Has had sex in exchange for goods, drugs, or money
  • Has had intercourse with a person who has a history of sexually transmitted diseases, or someone with unknown sexual history

It is important to remember that HIV or AIDS screening procedures are anchored in a human rights approach that honour and respect ethical principles. The conduct of such diagnostic procedures should be confidential and with informed consent of the individual undergoing the procedure. The diagnosis, should it turn out to be positive, should be accompanied by counselling, conducted by a trained professional.

When the test is performed, both the medical professional and patient should be knowledgeable about the window period, which is the period from the supposed infection (or contact) to the period when changes in the body can be detected. Typically, HIV-1 antibody tests have a window period of 25 days to observe the subtype B. Newer tests can also detect HIV presence through an antigen, around twenty or so days earlier than other tests.

Test results will often be described in two terms: sensitivity and specificity. Sensitivity pertains to the percentage of the results, which will come back positive, if the virus is present in the patient’s system. On the other hand, specificity is the negative results that indicate the absence of the human immunodeficiency virus.

There are also limitations to HIV screening procedures, and these limitations can result in dubious or erroneous results. A false positive means that the test indicates that the virus is present in a person without it, while a false negative will indicate the opposite.

How Does the Procedure Work?

For many standard tests, only a blood sample is required, which can be obtained through a pinprick on the patient’s finger. Blood tests are designed to check for antibodies closely linked to HIV infections. When the virus is present, the individual’s body will produce antibodies in direct response to the infection in an effort to protect itself. However, standard blood tests are not designed to immediately diagnose HIV infection, as the human body generally needs about two to eight weeks to produce antibodies that combat the infection. Other standard tests require urine or saliva to screen for HIV antibodies.

Diagnostic tests using saliva can produce faster results. In under thirty minutes or less, rapid antibody tests can determine the presence of HIV in a patient. Though fast, rapid antibody tests are as accurate as standard HIV screening procedures.

Another option for patients is a home testing kit. These do-it-yourself kits are created in the effort to keep the screening test confidential. Patients can perform the HIV test in the comfort of their home, which requires either blood or saliva to detect the presence of HIV antibodies. Some of these kits might still require mailing the sample collected at home to a medical lab, but the patient’s identity is still protected. The medical lab will usually phone in the results after about three business days. Saliva kits typically require samples collected from the upper and lower mouth, with results coming back in under forty minutes. It is still important, however, to undergo a follow-up test to confirm positive results.

HIV screening procedures also monitor the CD4 levels. These tests require a blood sample to determine the number of white immune cells with CD4 proteins on their surface. CD4 monitoring should be performed every three to six months during the treatment phase. Viral load tests can also come in handy when monitoring the amount of virus present in the patient’s blood. A low viral load means that treatment is effective in keeping numbers low. At the beginning of the treatment phase, the patient needs to undergo viral load monitoring every two to four weeks, and once every two months until there is no more virus present in the blood.

Possible Complications and Risks

There are no associated complications and risks with HIV screening procedures, especially since they are very minimally invasive and require a small amount of samples from the patient.

References:

  • Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. Department of Health and Human Services. Updated May 1, 2014. Accessed May 12, 2014.

  • Quinn TC. Epidemiology of human immunodeficiency virus infection and acquired immunodeficiency syndrome. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 392.

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