How accurate are self-test kits?

A laboratory technician displays a Bioline HIV testing kit. Kenyans can now take a HIV test in the privacy of their homes using an oral testing kit or a blood test kit. PHOTO | JOSEPH KANYI

What you need to know:

  • The oral HIV test is recorded as being 92 per cent sensitive (it will be positive in 92 per cent of the cases where HIV is present or the risk of having a false negative test is 8 per cent and 99.98 per cent specific (the risk of having a false positive test is 0.02 per cent).
  • In case of a positive test result, confirmatory testing should be done at a health care facility before starting on treatment.

Dear doc,

How accurate are HIV self-test kits (for the rapid oral HIV test)?

Patrick


Dear Patrick,

The rapid oral self-test kit checks for the presence of HIV antibodies in the gum exudate. This is an antibody test, which means you can have a negative test if you are still in the window period. This is the period between getting infected with the HIV virus and your body developing antibodies. The average length of the window period is 90 days.

The oral HIV test is recorded as being 92 per cent sensitive (it will be positive in 92 per cent of the cases where HIV is present or the risk of having a false negative test is 8 per cent) and 99.98 per cent specific (the risk of having a false positive test is 0.02 per cent). In case of a positive test result, confirmatory testing should be done at a health care facility before starting on treatment.

 

How long does it take for HIV symptoms to appear after contracting the virus?

Several weeks after getting infected with HIV, some people get acute sero-conversion syndrome. During this time, there is rapid multiplication and spread of the virus. There may be fever, joint pain, muscle pain, fatigue, lymph node swelling and a rash. Rarely, there may be meningitis and/or encephalitis. Most people do not notice these symptoms, as they may mimic other infections. The symptoms may last for several days or weeks then disappear.

After that, without treatment, it may take years to develop any other symptoms. Within the next five to seven years, there may be no symptoms at all or there may be sporadic flare ups of immune activation, showing up as different auto-immune illnesses. After about eight to 10 years, as the immunity goes down, opportunistic illnesses may begin to manifest, and these may affect different body systems including the skin, the gastro-intestinal system, the respiratory system, the nervous system, and cancer may also develop.

Taking highly active anti-retroviral treatment keeps the virus levels down, which allows for the immune system to recover and work well, and therefore prevent any opportunistic illnesses.


I have this habit of looking for oral thrush in people’s mouths especially when looking for someone to date, and this usually gives me a hint that the person could be HIV- positive. Are there other causes of thrush ?

Millie, Nairobi

 

Dear Millie,

The only sure way to know someone’s HIV status is by doing a HIV test. Once someone gets infected with HIV, without treatment, they can stay for eight to 10 years without getting any symptoms. Also, those on treatment and are virally suppressed will not develop opportunistic infections like oral thrush.

In addition, any condition that causes a low immunity can predispose someone to oral thrush. This includes HIV infection, diabetes, chronic liver and kidney disease, hormonal disorders, cancer, old age, very young age, alcoholism, and treatment with medications that lower immunity like steroids and cancer drugs.


What are the side-effects of ARVs?

For HIV prevention and treatment, a combination of either two or three medications are used. The medications used depend on different factors including the existing treatment guidelines, the unique characteristics of the patient, any other medication the person is taking, the ability of the individual to tolerate the medication and any other health conditions. Each medication used has different potential side effects and each individual responds differently to the different medications that are part of the treatment regimen. To know the potential side effects of a specific anti-retroviral medication, check the drug information that is available in the packaging or from a trusted source, or inquire from the pharmacist or doctor about the specific drug.


If I am on HIV medications and my viral load is undetectable (meaning that the virus isn't showing up on blood tests), can I still pass the virus to another person through sex?

When a HIV positive person takes the correct medication consistently, the level of the virus in the body and in the blood goes down. The amount of virus in the blood can be measured using a test called a viral load test, which is done regularly to see how someone is doing on medication. With good adherence, the target of treatment is to achieve an undetectable viral load. This means that the number of viruses has gone down to the extent that the viral load machines cannot detect any viruses in one millilitre of blood. It is important to note that undetectable viral load in blood doesn’t mean that the HIV is cured. The virus particles may be few in the body, but if you stop taking antiretroviral medication, those few viruses multiply very fast and attack your body.

When your viral load is so low that it is undetectable, the risk of transmitting HIV sexually is very low; it is negligible. However, there is still a small risk of vertical transmission through labour and delivery, and also through breastfeeding, and there may still be a risk of transmission through shared needles. If there is no proper adherence to medication, the risk goes back up. The HIV negative partner may also get infected from a different partner. Additional measures to protect the HIV-negative partner include use of condoms, behaviour change to reduce risk and use of preventive medication, as necessary.


I have heard that I can get HIV medication once a month instead of taking my drugs  every day. How does it work?

Due to continued research and innovation, new drugs are being developed in addition to new ways of providing these drugs. One of these developments has been two anti-retroviral medications given as intra-muscular injections once a month (or once every two months depending on the formulation). The injected drugs have a high concentration of the anti-retroviral medications which are released slowly over time, to provide the necessary concentration of the anti-retroviral into the blood stream.

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