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HIV-1 Viral Load Test

The HIV-1 Viral Load measures the amount of the HIV virus in your blood.

This test is used for those undergoing HIV treatment. It helps in selecting the right medications out of 20+ commonly used drugs against HIV, assess the response to the treatment and its success.

It usually takes 1 month to 6 months for HIV drugs to fully suppress the HIV virus in the body at which point viral load is described as undetectable. Those who have got an undetectable viral load are not infectious to others (i.e. U=U).


Window Period


Sample required

Blood from vein

Time for test results

Within 4 working days

Cost of test



Same day appointments

In Birmingham Clinic


Highly confidential service

And discreetly located clinics


Specialists in sexual health

From busy NHS clinics

How is it different from the HIV-1 Qual test?

The HIV-1 Viral Load test is a quantitative test that tells us the amount of HIV virus in the blood sample. This test is done in those who are known to be HIV positive and is a way of monitoring their infectiousness and response to HIV treatment.

The HIV-1 Qual DNA test is a qualitative test and identifies whether someone is HIV positive or negative.

When do I need an HIV-1 Viral Load test?

This test is meant for treatment and monitoring of HIV-1 positive patients. A Viral Load test will be carried out after initial diagnosis to form a baseline. Another test to be done at the start of HIV treatment with a follow up 1 month after. And then every 3-6 months.

This test is not a diagnostic test, however, in some cases, it is helpful in excluding in diagnosis of HIV-1 in cases where 4th generation antigen & antibody tests are equivocal.

Why does this not test for HIV-2 Viral Load?

HIV-2 Viral Load is a different test which is done for those who have got HIV-2 infection – this test is meant for treatment and monitoring of HIV-2 positive patients.

Unfortunately, the test for HIV-2 Viral Load is not widely available and not as accurate as for HIV-1.

How accurate is this test?

These are very sensitive tests and most routinely used assays can detect as little as 20 copies of HIV RNA in a millimetre of blood.

What do the results mean?

The patients who are on HIV treatment will normally have an UNDETECTABLE viral load. This means less than 20 copies of HIV RNA in a millimetre of blood. This means that your HIV treatment is working well and you can have unprotected sex without passing on HIV (please note that practicing safe sex is recommended even if you cannot pass on HIV to protect yourself from other infections).

Those with a previously undetectable viral load may experience a sudden appearance of detectable viral load occurs when the patient is not taking the medications or the medicines have stopped working (also called a ‘Blip’).

A Detectable Viral Load means there is a large amount of HIV in your blood. This means you are infectious and you need treatment to prevent your immune system from being destroyed. Detectable viral load can range from 20 to millions of copies of HIV RNA per ml of blood. When viral load is >100,000 it’s considered high from the point of view of selecting HIV medications.

Do I have to repeat this test?

You will need to repeat this test 1 month after starting HIV medication (or a new course) and every 3-6 months after this to ensure that the medications you are taking are still effective.

What happens if I stop taking my HIV medication?

If you have an undetectable HIV-1 Viral Load and you stop taking HIV medications, then the HIV virus becomes detectable again. This will result in a drop in your immune system and consequent ill health and becoming infectious to your partner.

There are, however, a few people with HIV whose immune system can keep the virus in check and therefore undetectable without taking any medications. They are called ‘elite controllers’.

When can I have unprotected sex?

If your viral load is undetectable on two occasions 6 months apart, then you can have sex without passing on HIV-1.

Please note being undetectable does not protect you against other STIs.

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Page reviewed by Dr. Manoj Malu (Clinical Director)

Last reviewed date: 21 April 2020
Next review due: 21 April 2023

Whilst this content is written and reviewed by sexual health specialists, it is for general guidance only. It is not intended to replace the advice of your clinician.