Though several different tests exist, there are three main categories
of HIV testing available on the market today. Every form of testing
listed below will fall under one of these three main categories.
Viral Load: People are usually
referring to HIV or AIDS infection when they talk of ‘viral load’,
although it can apply to other infections as well. Basically, ‘viral
load’ stands for the amount of virus in the body.
HIV works by making more and more
copies of itself throughout the body. Without treatment, viral load
can become very high (worse for patient). However, today’s
antiviral therapy (treatment) will actually stop the HIV virus from
making copies at all, thus preventing the viral load from increasing.
This is why early detection is so
important; you want to halt the viral load while it is already very
low, and prevent it from increasing. Though there is no known cure
for HIV, proper treatment can make the viral load so low it is very
unlikely to infect others.
- People newly infected tend to be very infectious.
The human body produces antibodies
(specialized proteins) in reaction to the HIV virus, or antigens in
general. In fact, the body will produce antibodies in order to help
combat almost any infection; it is a natural defensive response. An
HIV antibody test measures the amount of antibodies present in the
body in order to fight the HIV infection.
Of course, it can take 4-6 weeks, even
up to three months after infection, for the body to produce enough
antibodies for an accurate test result. Though this is considered a
‘Rapid Antibody Test’, the time frame is lengthier than others
and probably not ideal for those who want the absolute best health
care available. After all, the quicker HIV is detected, the better
the options a patient has.
- Antibody tests are the most common tests for HIV.
ELISA (EIA) Test
The enzyme-linked immunosorbent assay
test is one of the more popular HIV tests, measuring antibodies in
the bloodstream. Requiring a blood sample, the test is very simple,
relatively painless (minus the slight needle sensation of blood being
drawn), and involves laboratory testing. False results are possible;
your health care provider may order additional tests for accuracy.
- ELISA tests are the main antibody tests for HIV.
- Rapid testing can yield results in 10-30 minutes.
- Positive results don’t necessarily mean you are positive, but indicate you’ll need a second test for confirmation (Western Blot).
Western Blot Test
Western Blot is frequently tested as a
follow up to confirm the presence of antibodies. Typically, the test
is used to confirm a positive HIV diagnosis, or a positive ELISA.The
two tests together are 99% effective.
Unlike antibody tests, RNA testing is a
bit more direct, measuring the actual presence of virus material
(RNA) in the blood. Though there may be few symptoms during these
first few days after infection, the virus is continuing to produce
more and more of itself. RNA testing can track increases and
decreases of HIV viral load in order to evaluate treatment.
- Viral load tests are usually recommended only in very high risk situations where infection is likely. This is because the testing is less accurate, more expensive, and requires more laboratory resources.
Early Detection HIV RNA Test
HIV RNA testing can be taken much earlier than the antibody tests
above, before the body even begins to produce antibodies at all.
You’re looking at an early window of 9-11 days after exposure,
compared to 4-6 weeks with antibody tests, making RNA testing ideal
for best treatment options. In fact, the early test window is the
major advantage HIV RNA testing has over antibody testing.
- HIV RNA testing is the most sensitive, and accurate, early testing option for HIV available on the market today.
- Though the test window is much earlier, viral load testing is unfortunately less accurate than the two above, false readings more common. Subsequent tests are more often requested to confirm readings.
A major HIV protein, called P24, the
antigen being tested here is produced 2-3 weeks after infection bet
before antibodies are produced. Though these do give an earlier
result than antibody tests, they still aren’t recommended as early
as viral load RNA tests.
- P24- combination tests will detect over 95% of infections over 4 weeks of exposure.
- These tests can detect the P24 protein an average of 10-14 days after infection, although results are less reliable.
- The P24 protein is usually not detectable after 5 weeks.
We know antibody tests can take
anywhere from one to three months to yield an accurate result, but
the results are very accurate. So, we lose the option for earliest
medical treatment, but can be very reassured in the test results.
The tests themselves are also cheaper
than early detection RNA testing. On the other hand, what little
money is saved will almost certainly be spent on future medical
treatment- and quite a lot after that. In other words, the cost of
these tests are miniscule compared to what you will spend on future
medical treatment if you are in fact HIV positive. That being said,
costs will likely increase the more medical care that is needed, and
the later the virus is caught, the better odds more treatment will be
Early Detection HIV RNA Test
These tests are going to be a bit more
costly, and initial testing is less accurate; false positives are
more common. Of course, false results are easy to identify, provoking
the option for subsequent testing to confirm.
RNA testing can identify the virus
after just a few days, giving the best possible option for treatment.
This way, patients can start treatment when viral load is very low,
and keep it very low. The benefits here far outweigh any drawbacks.
- Remember, these tests are often only recommended in high risk situations. Otherwise, antibody testing is often given due to the higher accuracy of both tests combined.
- Did you know- it is possible, even common, to get HIV viral load levels so low, it’s all but impossible to pass the virus to others? The only way this can happen is through proper medical treatment.