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HTLV Testing

Window Period. 65 days

Sample(s) required. Blood from vein

Biological Marker. Antibody or DNA/RNA


HTLV 1 & 2 Antibody: 99%

Time for test results. 7 working days (exc. sat/sun)

Cost of tests.

HTLV 1 & 2 Antibody: £150 (recommended screening test)

There are estimated 20 million people worldwide with a HTLV-1 infection. It is a common infection in Brazil. Most people infected with HTLV have no symptoms or signs and may not know they are infected. A small minority, about 1 in 20, will develop complications but this usually occurs after several decades of having the infection.

In the UK, HTLV is a rare infection, and not routinely screened for as part of STI or antenatal screening. However, HTLV screening is undertaken in blood donation and organ transplantation services as a matter of routine as well as in the specialist medical practice of neurology, haematology and oncology.

It is estimated that in the UK 22,000 people are infected with HTLV-1, but less than 1000 are aware of the infection. Those who test positive for this infection are then not allowed to donate blood for the rest of their life.

Where required, the HTLV antibody screening test is the recommended test. If the antibody test is positive, then a PCR test is performed to determine if the presence of the HTLV virus is currently detectable or not. Both HTLV antibody screen and HTLV-1 PCR test may occasionally be requested at the same time in certain circumstances.

Same Day Appointments Available

Specialist & Friendly Professionals

Discreet & Confidential Service

The Process


In order to be most prepared and leave plenty of time for questions & discussions, we will ask you to fill out a simple questionnaire.


We will begin by running through your medical & sexual history, offer a physical examination and discuss any questions you may have.

Sample collection

If it is still appropriate to proceed with the HTLV test (and you would like to), we will take a blood sample from the vein.


Once you have received your results, we will discuss the next steps with you (inc. notifying your partners).

We follow guidelines set by

Medicine is a complicated subject and sometimes these guidelines don’t always hold the answers.

For example, treating an STI in a patient who has developed a resistance to routinely used antibiotics.

Unlike most private clinics, we have medical consultants here to help you navigate through such problems and get you on the right track in no time.

Frequently Asked Questions

About The Test

How do you test for HTLV?

HTLV can be diagnosed with the following tests:

  • HTLV 1&2 antibodies: a blood sample is taken to test for the presence of HTLV antibodies.
  • HTLV-1 proviral DNA and RNA PCR: a blood sample is taken in order to test for the genetic material of the virus.

HTLV is a lifelong infection, therefore, the detection of antibodies is useful as they signify if you have been exposed to the virus in the past. If you test positive for HTLV antibodies, a PCR test will be done to determine if the virus is currently detectable or not.

HTLV testing is not a part of routine GP blood tests, standard health checks, sexual health or antenatal screens.

When should I get tested for HTLV?

  • When you are donating blood, the NHS blood donation service screens your blood for HTLV before your blood is transfused to a recipient.
  • As part of medical investigations for symptoms and signs suggestive of symptomatic HTLV disease.
  • When you have had unprotected sex and you think there is a high risk of exposure (for example, having sex with someone from a country with a high prevalence of HTLV).
  • If you have been diagnosed with another viral infection (such as HIV, Hepatitis B, Hepatitis C).
  • If you have had a needlestick injury, and the source patient is at higher risk of having HTLV.

How accurate is the HTLV test?

HTLV 1&2 antibody screening test is very accurate, reaching a sensitivity of 99%. They are reliably used for screening of blood and blood products before transfusion.

What can affect my HTLV test results?

Recent viral infections or immunisation can rarely produce a false positive HTLV antibody test result.

Is HTLV testing recommended during pregnancy?

Antenatal screening for HTLV is not recommended due to its low prevalence in the UK and the absence of any serious effects on pregnancy or the health of the newborn. If you have HTLV and wish to breastfeed, it is recommended that you do not breastfeed for more than 6 months as the risk of infection until this point is low.

Specialist advice is given to women who are already known to be HTLV positive on how to reduce the risk of transmission to the baby.

Is my HTLV test confidential?


All information shared with us at Clarewell Clinics, including test results, is strictly confidential and will not be shared to the NHS or anyone else, unless you request otherwise. However, in the unlikely event that HTLV results are positive, your clinician will liaise with the NHS with your permission to ensure that you get the right care.

How can I prepare for my appointment?

You may want to wear a loose fitting or short sleeved shirt so that we can easily access your veins for your blood sample, however, no other preparation is needed for your appointment.

About The Results

How will I receive my HTLV test results?

You can receive your HTLV results by either text or a secure email.

Do I have to take any precautions whilst waiting for my HTLV test results?

Although the risk of HTLV test results coming back positive is very low, we recommend that you avoid having unprotected sex with any partners you may have, especially if circumstances suggest risk of HTLV exposure. You should also avoid donating blood whilst you wait for your test results.

What do my HTLV test results mean?

If you have a negative HTLV test, this means that the HTLV virus may not be present in your body. However, it is always recommended that you retest a few months later to ensure that your test result is conclusively negative. If you have tested too early, you may receive a false negative result as your infection is fairly new and you have not produced enough antibodies to be detected.

If you receive a positive result, you have the HTLV virus. It is important to remember that you will always test positive (once infected) for HTLV, even if the virus becomes inactive.

What happens if my HTLV test is positive?

In the unlikely event that your HTLV results are positive, your clinician will liaise with the NHS with your permission to ensure that you receive the correct care. Most people with HTLV-1 and HTLV-2 do not become seriously ill, and are able to live a normal life.

Do I have to tell my partner if I test positive for HTLV?

Yes, it is recommended that you inform your sexual partners that you have tested positive for HTLV.

Can I get a certificate of my HTLV test results?

Yes. Along with a text or email of your HTLV test results, we can email a certificate for official purposes.

If you require a certificate for your results please bring a form of ID with you to your appointment.

Next Steps 

In Clinic Care

Same Day Testing Available

Online Care

Same Day Telephone / Video Consultation


Sexual Health Consultation (inc. in test) £75

HTLV 1&2 Antibody Test (inc. consultation) £150


Health Insurance

Find out if you can claim your visit

Page reviewed by Dr. Manoj Malu (Clinical Director)
With assistance from Shannon Abraham

Last reviewed date: 12 January 2023
Next review due: 12 January 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.