HIV Infection, AIDS and Lab Testing

The virus that causes AIDS (acquired immunodeficiency syndrome) is known as HIV (human immunodeficiency virus). Progressively, HIV Infection impairs the body’s ability to combat infections and specific cancers. Typically, it weakens the body’s immune system by targeting lymphocytes, which is a white blood cell type that usually assists the body in fighting infections. Certain lymphocytes called CD4 cells or T-helper cells are major targets when it comes to HIV. The virus often binds to CD4 cells, gets into them, replicates within them, and later kills them.  

The viral load or the amount of HIV increases over time, while the number of CD4 cells left in the blood reduces. After a few years without treatment, there can be a drop in the number of CD4 cells to a certain point where AIDS-related symptoms and conditions begin to appear. With AIDS treatment, you can slow down the disease progression by lowering the amount of HIV in your body. Generally, this enables your body’s CD4 cells to stabilize or increase.  

As of now, there’s an estimation of 50,000 people in the U.S that are newly infected with HIV every year. And that is according to the Centers for Disease Control and Prevention (CDC). People living with HIV Infection in the U.S is estimated to be 1.2 million, and that almost 13% of those who are infected are not aware of it and can easily pass on the virus to others. In 2012, which is the year with the most recent statistics, almost 14,000 people with AIDS succumbed, and nearly 660,000 people have died since the start of the epidemic, as per the CDC.  

In 2013, according to the World Health Organization, as many as 2.1 million people worldwide were newly infected with HIV, 35 million people were living with HIV, 1.5 million succumbed to AIDS-associated illnesses.  

HIV can be spread in several ways: 

By engaging in unprotected sex with a particularly infected partner. In most cases, during sex, the virus can enter your body through the lining of the mouth, rectum, penis, vulva, or vagina. For those who have a sexually transmitted disease (STD) like bacterial vaginosis, gonorrhea, chlamydia, genital herpes, or syphilis, then you might be at a higher risk for or susceptible to acquiring HIV when having sex with infected partners.  

During pregnancy or birth. Around 25-35% of all untreated pregnant women who are also HIV infected will pass on the virus to their babies. Furthermore, HIV can be spread to babies via their mother’s breast milk, and that is if they’re infected with the virus. Once the mother undergoes the antiretroviral therapy (ART) as treatment during pregnancy, she will greatly lower the chances of spreading the infection to her baby.  

By sharing syringes or needles (like with intravenous injection drug abuse), and this can easily be contaminated with little quantities of blood from anyone infected with the virus.  

Via contact with infected blood. Currently, in the U.S., due to screening of blood for heat-treating methods, transfusion, and various treatments of blood derivates, there’s a minimal risk of acquiring HIV from transfusions. 

However, before donated blood could be screened for proof of HIV infection and before various treatments were discovered to destroy HIV in certain blood products, including albumin and factor VIII, HIV was often transmitted via transfusion of contaminated blood components or blood. In places of the planet where donated blood isn’t regularly screened or treated for HIV, contracting the disease via this mode of transmission is still a risk.  

Originally, HIV often brings about flu-like symptoms; however, some people might not exhibit any obvious signs or symptoms. HIV testing is the only way to figure out if or not a person has been infected.  

Just like other test results and medical conditions, a person’s HIV status is secured by the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule. Healthcare providers can never share it with employers, friends, or even family without written permission. If you test positive for HIV, however, it’s prudent that you notify your healthcare providers, all your sex partners, as well as anyone with whom you usually share needles. Often, counseling services are available from the healthcare provider or clinic that performed the test, and they can significantly help in advising you on everything you need to know. 

To treat an infected person, HIV status might be shared with healthcare providers who need to know. Furthermore, to find out the incidence of HIV and to offer the most suitable prevention and care services, every new case of HIV is reported to local and state health departments. Also, as of April 2008, information from all 50 states, including the District of Columbia, as well as five dependent areas (the U.S. Virgin Islands, Puerto Rico, the Northern Mariana Islands, Guam, and American Samoa) are collected using a uniquely designed confidential name-based reporting system. 

More About the Development of AIDS 

Initially, HIV brings about an acute illness that has non-specific, flu-like symptoms. At this time, the virus is available in huge numbers and is spread throughout the body. Approximately 2-8 weeks after the exposure, the individual’s immune system responds by releasing antibodies against the virus. Since HIV infects the immune system known as CD4 T-cells (also called T cells), it gradually begins to reduce their numbers. The person might be healthy for a decade or more; however, without treatment, HIV will continue to replicate and kill CD4 T-cells. Mostly, the virus remains in certain places such as the lymph nodes and brain, where it will hang on during the treatment.  

The term “AIDS” refers to the most advanced stages when it comes to HIV infection. Based on the CDC’s study, AIDS is usually diagnosed when a person’s CD4 T-cell falls below 200 cells/mm3. Also, AIDS is diagnosed when a person has HIV and an AIDS-associated illness, including tuberculosis or pneumonia, which is brought about by the microorganism Pneumocystis jirovecii (carinii). To people who have AIDS, it’s common that opportunistic infections are serious and sometimes fatal since the immune system is so destroyed by HIV such that the body can never fight off certain viruses, bacteria, parasites, or fungi. Furthermore, those with HIV/ AIDS are at an increased risk of acquiring neurological disorders, certain cancers, and a variety of other conditions.  

What Are the Signs and Symptoms? 

Initially, HIV brings about an acute illness that has non-specific, flu-like symptoms like enlarged lymph nodes, rash, sore throat, headache, fatigue, and fever. Some people do not exhibit any noticeable symptoms. For most people, those initial symptoms disappear after a couple of weeks. HIV testing is the only way to be certain if or not a person is infected. 

When HIV isn’t diagnosed early and treated, the result is infection and destruction of more CD4 T-cells, which decreases their numbers. Eventually, the affected person’s immune system might become weakened to the point that the person begins experiencing signs and symptoms like: 

  • Difficulty concentrating or memory loss 
  • Sores in the mouth or anus or on the genitals 
  • Rashes 
  • Persistent diarrhea 
  • Extreme fatigue 
  • Profuse sweating, night sweats 
  • Rapid weight loss 
  • Recurring fever 
  • Persistently enlarged lymph nodes 

For children who got infected with HIV before or at birth, these symptoms might start showing within a few years. And untreated children might have delayed development and frequently get ill. Children born with HIV usually acquire pneumonia.  

HIV can develop to AIDS when left untreated, and this is the most advanced stage when it comes to HIV infection. If you’re diagnosed with AIDS, you might get life-threatening diseases known as opportunistic infections brought about by microbes such as parasites, fungi, bacteria, or viruses. Usually, these infections don’t make healthy people sick. 

People with AIDS commonly have opportunistic infections that cause various signs and symptoms, such as: 

  • Coma 
  • Severe headaches 
  • Extreme fatigue 
  • Weight loss 
  • Abdominal cramps, nausea, and vomiting 
  • Vision loss 
  • Severe and persistent diarrhea 
  • Mental symptoms such as forgetfulness and confusion 
  • Difficult or painful swallowing 
  • Seizures and lack of coordination 
  • High fever or shaking chills for several weeks 
  • Soaking night sweats 
  • Coughing and shortness of breath 

Laboratory Tests 

Testing related to HIV/ AIDS deals with detecting the affected person’s response to HIV (antibodies) and/or the HIV antigen, detecting the viral nucleic acid, or measuring the amount of virus. HIV testing focuses on various things, such as: 

  • Screening 
  • Evaluate HIV’s resistance to relevant and available drug therapies 
  • Measure and track the amount of virus in the individual’s blood (the viral blood) 
  • Screen for HIV infection and diagnose it 

HIV testing is the only way to figure out if or not a person has been infected with HIV. Immune system monitoring, as well as early detection and treatment of HIV infection, can significantly improve long-term health. What’s more, when a person is aware of his or her HIV status, it might help in changing certain behaviors that can affect that person and others.  

Several organizations strongly recommend routine screening for HIV. (CDC)The U.S. Preventive Services Task Force (USPSTF) and the American College of Physicians (ACP) recommend that pregnant women and anyone between 13-64 years (or 15-65 years in the case of the USPSTF) should be screened for HIV infection at least once.  

However, certain individuals should get at least one test to know their status, even if they aren’t between 13-64 years old. These are: 

  • People diagnosed with a sexually transmitted disease, tuberculosis (TB) or hepatitis 
  • People who got a blood transfusion around 1978 to 1985 or engaged in sex with a partner who got a transfusion and eventually tested positive for HIV 
  • Any person who thinks they might have been exposed 
  • A healthcare worker who has direct exposure to blood on the workplace 

Screening at least annually is recommended for those at high HIV risk and is advised when a person: 

  • Has engaged in unprotected sex with multiple partners since the last HIV test 
  • Has used street drugs through injection, particularly when sharing needles or any other equipment 
  • Is a man who has practiced sex with another man (according to CDC, gay or bisexual men might gain from more regular screening, like every 3 to 6 months) 
  • Lives with an HIV-positive sex partner 
  • Has exchanged sex for money or drugs 
  • Has had sex with any person who falls into one of the categories mentioned above or is unsure regarding their sexual partner’s risk habits 

Different types of tests might be used for HIV screening: 

The most recommended screening test for HIV infection is the combination of the HIV antibody and antigen test. It’s only available as a blood test. Typically, it detects the HIV antigen known as p24 and antibodies to HIV-1 and HIV-2. HIV-1 has a higher prevalence in parts of the United States. 

On the other hand, HIV-2 is the most common type found in Africa. The amount of virus (viral load) and the level of p24 antigen increase significantly immediately after the initial infection. So, testing for p24 helps in detecting early infections before the production of the HIV antibody. Roughly 2-8 weeks after exposure, there’s a production of antibodies to HIV in response to the infection, and they remain noticeable in the blood after that, which makes the antibody test effective for detecting infections several weeks after exposure. Since it detects both antigen and antibody, the combination test increases the chances that an infection is identified soon after exposure.  

  • P24 antigen testing. It’s used alone (with no antibody test) and only in rare situations when there’s a question regarding interference with an HIV antibody test 
  • HIV antibody testing. In the U.S., all HIV antibody tests detect HIV-1, and certain tests have been introduced that can also detect HIV-2. Usually, these tests are available as tests of oral fluid or blood tests. 

Diagnosis 

If any of the mentioned screening tests turn positive, it should be followed by a second test to determine a diagnosis. The second test is an antibody test that’s quite different from the first. When the second test doesn’t coincide with the first, then a third one is performed to detect the RNA or the genetic material of the virus.  

In 2014, the HIV testing recommendations were updated by CDC to incorporate a new testing protocol that has been approved by the Clinical Laboratory Standards Institute (CLSI) to: 

  • – Screen for HIV by using a combination of HIV antigen/ antibody test, then 
  • – Ensure to verify a positive by using a second HIV antibody test that tells the difference between HIV-1 and HIV-2. 
  • – In case the results of the first and second test don’t coincide, then the next test to take is an HIV-1 RNA test (NAAT, nucleic acid amplification test). The test will be considered positive only if the HIV-1 RNA is positive.  

The two tests, once commonly used for testing HIV infection, HIV-1 immunofluorescence, and HIV-1 Western blot, are not part of this new protocol and shouldn’t be used since these tests identify antibodies later in infection (approximately 28 days) and might give a false-negative result.  

Other tests: 

  • CD4 count. It measures the blood’s number of CD4 T-cells. It’s ordered when an individual is first diagnosed to obtain a baseline assessment of their immune system and is also performed at intervals to monitor the status and therapy of the immune system. When a person is doing good in treatment, this test might be performed annually.  
  • HIV viral load testing. It measures the blood’s amount of HIV. It’s carried out when an individual is first diagnosed to help in determining the status of the disease and is also performed at intervals to monitor therapy’s effectiveness.  
  • Phenotypic resistance testing. It’s sometimes performed for those who are resistant to multiple antiretroviral drugs to assist in guiding treatment. The test generally evaluates if or not different concentrations of antiretroviral drugs can inhibit the individual’s strain(s) of HIV. 
  • HIV genotypic resistance testing. It’s ordered when someone is originally diagnosed to figure out if or not the specific strain(s) of HIV that the individual has is resistant to specific antiretroviral drug therapies. It’s also performed when treatment is altered or when there’s proof of treatment failure.  

People who’re considering taking the drug abacavir might be initially tested for the gene allele, HLA-B*5701. In case they’re positive for it, then they’re at an increased risk of acquiring a potentially severe hypersensitivity reaction and, so, another drug should be recommended.  

Some other laboratory testing might be ordered as part of the general care of an HIV-infected person. Certain tests might be performed to identify and track the treatment of opportunistic infections, drug toxicities, and complications. Also, testing might be performed at intervals to evaluate the individual’s health and organ function. A few examples include: