HIV & AIDS: What Are They and How Are They Diagnosed?

Determination of whether a patient has HIV or AIDS is based on the results of an HIV test. An HIV test, tests the patient's blood, urine, or saliva for the presence of HIV antibodies, the virus, or other viral components. A patient is diagnosed HIV+ if he/she test positive for the presence of any of the aforementioned HIV antibodies, virus, or viral components because the presence of these things in the blood, urine, or saliva indicates that the patient has been infected to the HIV or AIDS disease.

More Specifically:

An HIV antibodies test is especially accurate in indicating whether the patient has been infected with HIV because it documents the body's response to infection. This is done by testing for the presence of special proteins produced by the body upon in reaction to being infected with the HIV disease. These proteins are called antibodies. A patient who tests positive for the presence of these antibodies indicates that the body has already begun to fight the infection and is diagnosed HIV+. Similarly, a patient who is absent of the HIV antibodies is diagnosed negative of the disease. HIV antibodies are usually detectable within a period of 6 -12 weeks following infection.

The diagnosis that a patient is HIV+ does not necessarily mean that the patient has AIDS. The progression of HIV is monitored with a CD4+ T cell count and measurements of HIV RNA in the blood.

The T cells in the immune system are "responsible for defense against cancer cells, certain viruses, and other pathogens that grow within cells (intercellular parasites)" (Cohen, 2009, p. 369).

CD4+ T cell count measures the number of CD4+ T cells in a patient's blood and assesses the health of the body's immune system (UCSF Medical Center, 2009). "The CD4+ T cell count correlates with a person's risk of developing opportunistic infections and is a useful marker for HIV disease staging and treatment planning" (UCSF Medical Center, 2009). A normal T cell count means that the immune system is still functioning at a healthy and safe level. HIV causes CD4+ T cell counts to lower, when these cell counts drop below a critical level, the patient is then diagnosed with AIDS and susceptibility to opportunistic infections progressively increases.

Measuring HIV RNA- HIV belongs to a group of viruses called retroviruses, meaning "backward viruses," and relates "to the way in which the viruses reverses the typical order of genetic action" (Cohen, 2009, p. 376). Viruses that belong to this group have RNA as genetic material instead of DNA (Cohen, 2009, p. 376). However, these retroviruses, dissimilar to other RNA viruses, "transcribe (copy) the RNA into DNA to reproduce inside the host;" the resulting DNA "enters host cell's nucleus and becomes part of its genetic material. There, it may direct the formation of more viruses or lie dormant and undetected for long periods, even years, before being triggered to multiply and cause disease" (Cohen, 2009, p. 376). Measuring the HIV RNA levels in a patient's blood is indicative of how active the virus is in the body.

The Difference Between HIV and AIDS:

HIV (Human Immunodeficiency Virus) is the virus that causes AIDS in the body, but is not actually AIDS; it is merely an infection of HIV. HIV is not harmless however, it causes the destruction of the body's immune system over time. Most patients who are infected with HIV will develop AIDS in their lifetime as a result of the HIV infection. An HIV infection is not fatal and with proper treatment the development of AIDS can be delayed for 10+ years.

AIDS (Acquired Immunodeficiency Syndrome) "is the advanced stage of infection caused by the human immunodeficiency virus or HIV" (UCFS Medical Center, 2009). When a HIV patient develops AIDS, his/her immune system has been severely compromised or destroyed and can result in the development of opportunistic infections or cancer, or a combination of the two (CDC, 2006). Since the patient has a compromised immune system, fighting of these illnesses is challenging, and although these infections can be managed with medical treatment and remedies, patients may ultimately die from these infections rather than the actual AIDS disease (UCFS Medical Center, 2009).

References

CDC. (2006). What is AIDS. Center for Disease Control and Prevention. Retrieved November 9, 2009, from http://www.cdc.gov/hiv/resources/qa/qa2.htm.

Cohen, B. J. (2009). Memmler's The Human Body in Health and Disease, 11^th Ed. N.Y.: Lippincott Williams & Wilkins.

UCSF Medical Center. (2009). HIV/AIDS. University of California, San Francisco Children's Hospital. Retrieved November 6, 2009, from http://www.ucsfhealth.org/adult/medical_services/infect/hiv/index.html.