HIV Self-Test at Home and Fingerstick Tests: How Accurate Are They?

Some people never go for an HIV test at a hospital because they are afraid of bumping into someone they know, or of how others will look at them. HIV self-test kits have helped a lot of people take that first step. The World Health Organization recommends self-testing as one of the standard ways to test for HIV, and in Thailand, kits registered with the Thai Food and Drug Administration (Thai FDA) are legal to use. But for the result to mean something, you need to understand how the kit works and when to use it.

What is an HIV self-test?

It is a kit you can use yourself at home. There are two types of sample:

• Fingerstick blood. You prick your finger with the spring-loaded lancet in the kit and drop the blood onto the test strip or well. Results take from a few minutes up to 15 minutes, depending on the brand.
• Oral fluid. You swab along your upper and lower gums and wait about 20 minutes for the result.

Almost all self-test kits look for antibodies, which your body only makes some time after infection. That means there is a period when someone is infected but the test cannot pick it up yet. This is called the window period. Oral-fluid tests usually turn positive a little later than blood tests.

Comparing the three types of test

These figures come from the US CDC and cover most people. For the full details, read HIV window period and when to test.

Advantages and limitations

Advantages

• Convenient, private, and you can do it at any time
• Fast results, which makes it easier for people who have never tested to get started
• Useful as an initial test before starting PrEP or PEP, together with an online consultation with a doctor

Limitations

• Testing too early can give a false negative
• Mistakes in the steps, such as too little blood or reading the result too early or too late, can make the result wrong
• A positive result is only a reactive result that needs confirming; it is not yet a diagnosis
• It does not test for anything else, such as syphilis or hepatitis

How to get a reliable result

1. Choose a kit registered with the Thai FDA (or your country's regulator) that has not expired, and store it at the temperature on the label.
2. Read the instructions or watch the manufacturer's video before you start.
3. Wash your hands in warm water. Warm fingers bleed more easily.
4. Add the sample and the buffer solution in exactly the amounts stated.
5. Set a timer and read the result at the time given in the instructions, not before and not long after.
6. If the control line does not appear, the test is invalid and you need to test again.

You have your result. What next?

Negative (non-reactive)

• If you tested more than 3 months after your last risk and have had no new risk since, the result is reliable.
• If it has been less than 3 months, a negative result only tells you your status from some time before. Test again on schedule.
• If you have ongoing risk, consider PrEP, the medicine that prevents HIV before exposure.

Positive (reactive)

• Try not to panic. False positives happen, so you need a confirmatory test at a clinic or hospital using standard methods.
• If infection is confirmed, today's antiretroviral treatment gives people a life expectancy close to everyone else's, and once the virus is undetectable, HIV is not passed on through sex. Read HIV treatment and U=U.
• If it all feels overwhelming, you can call 1323, Thailand's free 24-hour mental-health hotline (Thai language; ask for English support).

Things to know if you are on PrEP or PEP

If someone becomes infected while taking antiretroviral medicine, the drugs can slow down antibody production. A self-test may therefore stay negative for longer than usual. People on PrEP should test at every scheduled visit, every 3 months, and tell their doctor straight away if they get a fever, sore throat, rash or swollen lymph nodes, which can be symptoms of early infection.

At Dr. Kris Clinic, for people receiving PrEP or PEP remotely who do not yet have a lab blood result, I ask for a fingerstick test before starting the medicine, then schedule repeat tests according to standard guidelines during and after treatment.

Where can you get tested?

• Thai nationals covered by the Universal Coverage Scheme can get a free HIV test at their registered hospital, and can also get free self-test kits through the Pao Tang app, subject to the conditions of the National Health Security Office (NHSO).
• Anonymous clinics, community organizations and private clinics. Foreign residents and visitors can test at private clinics and hospitals.
• At Dr. Kris Clinic, you can test at the clinic, or we can send you a fingerstick kit together with an online consultation with a doctor. English-speaking consultations are available. See the remote service details in Online PrEP/PEP through telemedicine.