HIV Tests And HIV Testing -- Questions & Answers
What is an AIDS test?
Strictly speaking there is none. Since AIDS is a syndrome it isn't something that can be tested for. AIDS test has come to be interchangeable with the term HIV test.
OK, then what is an HIV test?
This is when a person is tested for HIV. Some tests look for antibodies to HIV and some tests look for the RNA of the HIV virus itself. Antibodies are made when the body is exposed to a virus. Testing for the HIV virus directly is very expensive and must be done in strictly controlled conditions to avoid contamination, there for testing for HIV antibodies is most widely used.
Can a person test negative and have HIV?
Yes, sometimes the person has been tested before the antibodies develop, this can take from one week to one month. Some people, for reasons unknown will test negative because of genetics. There has never been a medical test where someone doesn't test incorrectly, it's just humans are so different no test is 100% accurate. HIV testing is 99.8% accurate though.
Do you just take one test?
Yes, you give one test, but that blood test may go through more than one lab procedure.
A person is giving pre-testing question and asked information
A person must voluntarily consent to the HIV test
Blood is drawn from the person
Blood is sent to the laboratory for actual testing
The first test if for HIV antibodies. If this comes back negative, meaning no HIV antibodies are found, the person is considered HIV negative.
If the first test shows HIV antibodies the test is repeated.
If this test is found to be positive additional tests will be ordered to eliminate false positives.
What are tests for HIV antibodies called?
They are called ELISA (enzyme-linked immunosorbent assay test) and the Western blot test.
What is the ELISA test?
This is the first test done when a person comes in for HIV testing. This test is very sensitive to HIV antibodies and isn't often wrong. A negative ELISA test is unlikely to be wrong. However if the person has come in before antibodies have developed he can still have HIV and test negative. In a very few instances ELISA will show a positive for antibodies which are not antibodies to HIV. The ELISA test is usually performed twice on the sample of blood.
What is the Western Blot test?
This test is also looking for antibodies to HIV. It is usually performed as a back up when the ELISA test comes back positive. This test not only looks for antibodies but three groups of specific proteins that for a viral envelope of the HIV virus. At least two of the three proteins must be present for this test to be declared positive. For diagnoses of HIV infection both Western Blot and ELISA must be positive. It is very unlikely for a person to have a false positive to both test, but it has happened, but less than a handful of cases have been confirmed.
How are the tests different?
Both Western Blot and ELISA are used to detect antibodies to HIV. They both analyze the fluid portion of blood call serum. Serum is the same as blood plasma, except it has no proteins that cause clotting.
The ELISA test looks for antibodies the immune system has made to fight off HIV.
The Western blot is looking for the specific antigen or part of the virus, which the antibody is targeted for. In other words when the antibody goes to kill off the virus, it looks for a specific part of the envelope of proteins that surround the virus so it can attack it. This is the part or antigen that Western Blot looks for. The Western blot is more expensive and takes longer than the ELISA test. It is not formatted for automated testing, like ELISA is, therefore it is done after the ELISA test.
Can you test for the virus itself?
Yes there is the PCR (polymerase chain reaction) test and p24 test.
Why don't they just do them first?
The tests for HIV directly are very expensive and subject to strict laboratory conditions. They are easily contaminated so the environment must be very well controlled. Since the presence of the virus will cause the body to make HIV it is better to test for the antibodies.
Testing for the virus directly is most helpful to doctors for tracking the progression of the illness. It is also used for newborns, who may not have the actual virus but may have had some of the HIV antibodies transferred by an HIV positive mother via the placenta.
What is the PCR test?
This test allows small bits of genetic material to be amplified so they can properly be identified as belonging to a specific virus.
What is the p24 antigen test?
This is similar to the ELISA test but instead of testing for antibodies against HIV it tests for p24, a protein found in the core of HIV. This test is performed on a person's blood plasma or other body tissue. HIV proteins are found in the bloodstream at all staged of the illness but are most abundant after the initial infection and later stages of AIDS.
I heard about an HIV tests that uses saliva
Yes there is a test that uses similar laboratory procedures, they are as reliable as blood tests but not typically as available.
Why not just use the saliva test?
Usually the blood cannot only be tested for HIV but other sexually transmitted diseases as well. Using saliva only could only detect the HIV. It is a good idea to get tested for a multitude of STDs when you get tested for HIV.
What about the home test?
Because of confidentiality concerns of getting an HIV test at your doctor or a clinic, a home test was devised. Currently there is one FDA approved home HIV test and it has been determained to be accurate and it usually goes something like this:
A person uses a small needle like device to prick the end of your finger with. You take a few drops of your blood and put it on the absorbent paper provided.
Each piece of this paper has a special code of unique ID numbers on it. This code allows the person doing the test to receive his results without identifying himself by name.
The dried blood drops are mailed to an HIV testing center
The blood is tested using the ELISA and western blot tests.
A person calls the clinic and receives his results by identifying himself with the code numbers.
Are home tests really accurate?
There is only one FDA approved home HIV-1 test. This test has been through many clinical trials and has proved as accurate at other forms of HIV testing in clinical and doctor's offices. This home test is called "Home Access Express HIV-1 Test System." Home Access Health Corporation manufactures it.
There are however many other home HIV tests for both HIV-1 and HIV-2 that are marketed. The FDA has not approved these tests.
How do the unapproved HIV home tests work?
The advertisers of the unapproved HIV home test kits generally have a visual indicator such as a red dot to indicate you are positive for HIV antibodies. Most of these tests use a finger prick for your blood, but others use saliva.
The blood or saliva sample is collected and added to a plastic device containing a specialize strip of paper. Then a developing solution is added and this will determine if HIV antibodies are or are not present.
This approach is fast and simple but may produce less accurate results
No other HIV home test, other than the test by Home Access, has gone through the extensive scrutiny of FDA approval. Also remember even though the tests may claim to be independently tested, the FDA has not tested the laboratories to make sure the labs are using correct standards.
Is it worth your time, money, mental anguish and your life to gamble on an unapproved HIV home test kit? Only you can answer that question.
I have received feedback from a user named Adam who has informed me that a test he bought a Walgreens to administer to other people has given him at least 15 false positives. So it may be worth noting that other people have not had great results with these home tests.
(Note: Thanks Adam for providing feedback and corrections to the HIV home test section of my website. I appreciate your feedback and time).
How long from initial HIV infections till show up?
Within one to five days after exposure the body will produce antibodies to HIV. In controlled tests, where exact date of infection can be determined, it takes from one week to three months to for the antibodies to build up to levels where they are detectable by standard tests.
Because of the real time possibilities that a person does not know which sexual act infected him, the three month window, noted above should be extended to six months. That would be 3 months on either side of an HIV test or six months total.
In other words nearly everyone, though it is never 100% certain, who is going to test positive for HIV antibodies will do so after 6 months.
You said "standard" tests. What is that?
These are the common tests used by the medical field. Researchers who study people and habits can use much more sophisticated testing to detect it early.
Why not test for everyone gay or straight?
Due to cost and time, the more sensitive the test the more it costs and the more likely it is going to be prone to error. It makes no economic sense to test people who most likely will not have it.
Why is it necessary for researchers to know right away?
Because they are collecting data and studying habits and they need to be accurate as possible. Also with other diseases such as lassa fever you can actually tell how severe the illness is going to be by how fast the body develops antibodies. In the case of lassa fever, a dangerous viral illness, if the body produces antibodies within 24 hours of known initial exposure the illness will be less severe.
Why is that?
Because when a virus gets into your body it needs time to find the correct cell to "hijack" and reproduce. If the virus has only made a few copies of itself the immune system only has to wipe out a few cells. The longer it takes for the immune system to figure out something's wrong the more virus there is to fight off
Can a person test positive for HIV after getting a negative test?
Yes, assuming you have not had additional sex with another partner, your body will only produce a positive result if your body makes the antibodies. So if you had sex in August, got tested in October your body may not start producing antibodies till December, so you would need another test to confirm the first test is truly negative. Also during that time you must limit your sexual activity.
Testing does NOT predict the future only your past.
Can an HIV test prevent AIDS?
No, it only is an indicator of HIV status. Just like a lung x-ray cannot prevent lung cancer. It can only tell what you've been doing in your past.
What's the typical wait between testing and results?
It averages one to two weeks. Your testing facility can provide you with exact details.
How much does it cost to get tested?
The cost of HIV testing varies from doctor to doctor and is not always covered by insurance. It is best to check first for insurance coverage. In addition some people may not wish their insurance company to know they are being tested for HIV.
Cost on a nationwide average is around $59.00. Again this can very greatly from state to state.
Why not just donate blood to get a free HIV test?
From the Red Cross Website they answer it like this:
The Red Cross tests blood products for HIV; however, anyone interested being tested for AIDS should NOT donate blood in order to get tested. Our community needs healthy donors. You can contact your local health department for AIDS testing. Testing through your local health department is free and may be done anonymously.
Should I be tested anonymously?
Yes, if at all possible. Insurance companies track and share information with each other and you may be denied coverage. Officially you cannot deny insurance coverage but you can be turned down for no reason, so an insurance company may just flatly turn you down, and never state your getting an HIV test was the reason.
What exactly has to happen for me to be tested "positive"
The ELISA test must be done. The ELISA test will be redone. Then the Western blot test will reaffirm the ELISA test.
What does it mean exactly if I test "negative"
It means the body has not produced antibodies for the HIV virus. Basically it means you were HIV free six months prior to the test.
I had a friend who's test was "unresponsive," what is that?
This is simply another name for negative.
Someone I knew had a test labeled "undetermined."
Undetermined or inconclusive means the results are mixed. For example the ELISA test could be positive and the Western blot test negative. This means the person should be tested again within three to six months.
Are there false negative tests or false positive tests?
Yes but it is very rare, but it has happened. No matter what medical test you have, there are always some people that test incorrectly, despite proper lab procedures.
How accurate is HIV testing?
HIV testing is considered 99.98% accurate, which is as accurate as a medical test can be,
Who is likely to get a false positive or false negative test?
It is impossible to know for sure, but a person who has had a blood transfusion would be a likely candidate. A baby born to an HIV infected mother would be another. Recent vaccinations for the flu or hepatitis can result in an "Inconclusive test." The person doing the testing should ask you questions before taking the test to rule this out.
Can you be forced to get an HIV test?
Certain people can, for instance the armed forces are routinely tested. In certain areas firefighters, EMTs, paramedics and policemen are required to maintain HIV testing prior to or during their careers. Some states require prisoners or those arrested for prostitution to be tested. Hospitals may require their workers are tested, especially those who do invasive procedures. In general you cannot be forced to take one.
If a minor takes the test must his parents be told?
HIV testing for minors are subject to the same laws as other medical testing, some states allow minors to be tested without parental notification, others do not.
Do insurance companies find out the results?
Yes they do, and they often share information. For this reason alone if at all possible I recommend anonymous testing. Magic Johnson was first diagnosed when he took the test for an insurance policy.
Does prenatal care involve an HIV test?
Not always, but because it's thought certain meds can prevent transmission of HIV from woman to fetus, it is usually only done at the request of the mother.
If I test positive who will the lab tell?
Laws of every state require that people testing positive or negative be reported to state health departments for tracking statistics. A few states require the names of people to be reported, while other states will accept anonymously tested people.
If names are reported the state health agency has the obligation to track and report your status to anyone who you may have infected, including past sex partner and IV drug sharing partners. This is the same for any other sexually transmitted illness.
Can I legally find out the status of a former sex partner?
Not without a court order, and then it is most often suggested that the person first get tested twice before proceeding with a court order.
Should everyone get tested?
Only people who are at high risk or believe themselves to be exposed should be tested. Although it never hurts, it would be similar to having an EKG if you never had any heart problems. It's up to you.
Why would anyone not want to get tested?
Fear seems to be the biggest reason given. People have participated in such risky activity they assume they are and don't want to confirm their worst fears. Some cannot get the test done anonymously. Cost of testing is another reason. Some people fear they will be labeled gay.
Can a person with HIV get it and die before the person that infected him?
Absolutely yes, some people have stronger immune systems than others. General health also effects length of illness. A person who has taken care of their body has a greater chance of surviving longer than one who has neglected his body.
HIV lies dormant in the body and it is THOUGHT that other viral illness may play a part in triggering or stimulating HIV cells into an active state. For instance HIV becomes active and reproduces when T-helper lymphocyte cells respond to fight other illnesses. The most common viruses to stimulate HIV are hepatitis-B, CMV and the herpes viruses, including genital herpes, cold sores and shingles, chicken pox, and HPV6.
Can a person be a carrier of HIV?
It's thought no, but we really don't know for sure.
A carrier is someone who definitely has the disease but will not develop the illness. The infamous Typhoid Mary is a great example of a woman that had typhoid fever and infected many other people but did not get typhoid fever. She only carried the virus. Another example is a cold sore also called fever blister. About 95% of all American carry this virus, most get it before age 10, but some never get a cold sore and for some it is a persistent problem.
Because HIV is not common and only high risk people are tested the data is unreliable. We think everyone who has HIV will get it. Currently about 10% of all known HIV infected people, not on drug regiments remain without symptoms after 10 years.
There are a few exceptions a handful of people do seem to have HIV and are carriers.
Some people have genetic mutations, which prevent HIV from properly attaching to the T-cells. So HIV can't harm them, but they can transmit HIV.
Another example is of a man who had gotten it from a transfusion. He continued to have unprotected sex with his wife and she nor the child she gave birth to, were ever infected. He remains healthy still and it's been 25 years. But this people are exceptionally rare.
Can you tell someone has HIV by looking at them?
Most likely not, though a person who is on HIV cocktail drugs and some in later stages of AIDS get a certain "AIDS look" as it's called, but that is not common to everyone. Certainly you can't tell an HIV infected person in the initial stages of infection when he can spread the illness.
(insert AIDS LOOK LINK)
How long is the incubation period for HIV?
Incubation refers to the time of silent phase of infection to the active state of infection. Without medication, it averages about 10 years. This statistic is very sketchy though, because unless you are tested regularly and routinely it's difficult to tell exactly when you were infected. It can be as quick as 18 months to over 10 years.
What are false negatives?
This is when your HIV test shows you are negative and you actually have HIV in your system. This can occur because your body hasn't started to make antibodies, or lab errors. This is why you need to get tested several times.
Are there false positives?
Yes, there have even been lawsuits because people were told they had HIV and charged up their credit cards, quit jobs and prepared for their death only to find out the test was wrong. This is why no matter what your test is you need to follow it up again.
Is this common?
It is not too likely your test will be in error but it's not unheard of, especially for a "negative" test you want to err on the side of caution. And also remember for whatever reason there are always people that produce inaccurate test results for any medical test. Not only tests for HIV but even pregnancy. Something in their body chemistry produces inaccurate results for that particular test, and it's no one's fault.
Testing in Africa is difficult because it's estimated over 90% of people living in sub-Sahara Africa have antibodies for malaria. Some types of malaria antibodies will give a positive reading for HIV.
What is a T-helper cell count?
T-helper cells are one of several types of white blood cells that form the core of the immune system. "T" stands for thymus, which is a gland in the upper neck. Here is where T-helper cells mature after originating in your bone marrow. Bone marrow is the filling of the bone. If you crack open a chicken bone you can scrape the "filling" so to speak out and see what marrow is.
There are three kinds of T-helper cells
T-suppressor cells give feedback on the activity of the immune system and keep immune responses in check to prevent excessive immunity.
Cytotoxic T-cells attack and destroy cancer cells
T-helper cells link the branches of the immune system and manage the body's immunity.
T-helper cells are the only cells that have CD4 receptor sites on their surface and thus are the only ones HIV can attack. Reduction in these T-helper cells is what doctors used to suspect AIDS before they had a test for HIV antibodies in the early to mid 1980s.
By examining the ratio of T-helper cells to T-suppressor cells one can get an idea of the health of the immune system. T-suppressor cells regulate the immune system by stopping the immune system from destroying healthy body cells as they fight against an illness.
As you can see the T-helper and the T-suppressor cells balance each other. For healthy people with no immune system problems the number of T-helper cells is usually about double the amount of T-suppressor cells.
However as HIV infection develops and become AIDS the number of T-suppressor cells overtakes the number of T-helper cells. This is the first signal the immune system is failing.
What is a normal T-helper cell count?
Healthy adults have between 600-1200 cells per unit of blood. By monitoring the count of T-helper cells physicians can see how the HIV infection is progressing.
What is a low T-helper cell count?
People become vulnerable to infections and diseases when the T-helper cell count goes below 200. When an HIV person with has a T-helper cell count of 200 or below he is diagnosed with AIDS.
So people are OK as long as their T-helper cell count is above 200?
Yes and no, it depends on the person. At a count of 500 some people get opportunistic illnesses and others don't. The overall health of a person BEFORE he got HIV also contributes. Other factors such as drug use, both prior and current adds stresses to the immune system. When the count lowers below 100 some sort of severe illness is common.
Do the T-helper cells count go back up?
Yes they will fluctuate up and down, even without meds, but usually they don't return back as high up as they once were.
Do people ever have low counts and not get sick?
Yes this has happened. Again the T-helper cell count is only one indicator, it's the strongest indicator but some people have counts as low as 10 (TEN) and are still not ill. A lot has to do with your body's overall fitness and other illness and traumas it has suffered either prior to or after HIV infection.
Why do the counts fluctuate?
It's a bodily function. Even in healthy people the counts of T-helper cells go up and down from morning to night. During every illness the number of cells will go down even for non-HIV infected people, then as the body fights off infection it rebuilds.
Remember every single day your body is fighting off germs successfully. The immune system is in a constant war. This is why you can stick your hand in mud and not get an infection.
It is not the COUNT of the T-helper cells that is important, it is the change in a given amount of time that is important. This will indicate the health of the immune system.
What is a viral load?
Viral load tests answer the question how much HIV is present in a sample of blood. The amount of HIV in a system is an indicator of the progression of the illness. What this test does is it looks for the RNA of the HIV virus. The greater the amount of HIV RNA the greater the burden is on the body. Today this is mainly used to monitor the various HIV cocktail drugs and how effective they are in fighting HIV.
I've seen people say their viral load is undetectable?
Each year the tests for HIV RNA get more and more sophisticated and can detect smaller and smaller amounts of the RNA, but every test has limits. If a viral load tests says no RNA from the HIV virus is present, the person is said to be "undetectable," because the RNA doesn't register on that test at all.
So the person is cured?
No, the virus is dormant and because the RNA tests are not sophisticated enough to detect every single piece of HIV RNA in your body, it is still there but in such minute amounts it can't be verified by any current viral load test.
Can the person transmit HIV if he is undetectable?
It is thought yes, it's not 100% sure though. Again, generalized tests say this has happened but because HIV is 100% lethal proper testing with standard medical procedures this can't be done.
Are all the tests for viral load the same?
No, there are several different techniques. The most common is PCR (polymerase chain reaction). Other types include b-DNA (branched-DNA signal amplification) and NASBA (nucleic acid sequence-based amplification. Each technique is effective at detecting the genetic material of HIV.