Human T Lymphotropic Virus Type I-II (HTLV)

What is the Human T-Lymphotropic Virus Type I-II (HTLV) test?

The HTLV-I & HTLV-II blood test detects antibodies produced by the immune system in response to infection with Human T-Lymphotropic Virus types I and II. HTLV is a retrovirus that infects T-lymphocytes, a type of white blood cell involved in immune regulation.

HTLV-I is associated with specific neurological and haematological conditions, while HTLV-II is less clearly linked to disease but remains clinically relevant. Most infected individuals remain asymptomatic, but a small percentage may develop serious long-term complications.

This test is used to identify exposure or infection, particularly in screening, diagnostic, and public health settings.

Why do I need an HTLV-I/II test?

HTLV infection is often silent for many years. Testing is important in risk assessment, diagnosis of related conditions, and prevention of transmission.

You may need an HTLV-I/II test if you:

• Have unexplained neurological symptoms
• Are being investigated for certain blood disorders
• Have lived in or travelled to endemic regions
• Had blood transfusions or organ transplants
• Have a sexual partner known to be HTLV positive
• Are pregnant and require viral screening
• Need screening for donation or immigration purposes

Conditions associated with HTLV-I include:

• Adult T-cell leukaemia/lymphoma (ATLL)
• HTLV-associated myelopathy (HAM/TSP)
• Chronic inflammatory or neurological symptoms

Benefits of the HTLV-I & II test

• Identifies HTLV exposure or infection
  Detects immune response to the virus.
• Supports diagnosis of rare neurological conditions
  Relevant in unexplained myelopathy.
• Useful in haematological investigations
  Supports assessment of certain blood cancers.
• Important for transmission prevention
  Helps reduce spread through early identification.
• Clinically recognised screening test
  Used in transfusion and transplant medicine.
• Simple blood test
  Requires only a single sample.
• Supports pregnancy and donor screening
  Important in public health contexts.
• Guides further confirmatory testing
  Indicates need for specialist follow-up.

Step by step – how the test works

You can access HTLV-I & II testing UK-wide through two options:

1. Clinic appointment
   Attend your nearest UK clinic, where a healthcare professional will take your blood sample.
2. At-home or hotel visit (£60 extra)
   A qualified phlebotomist comes to your home or hotel for sample collection.

Your sample is analysed in an accredited UK laboratory, and results are delivered securely.

Your results explained

Negative HTLV-I/II antibodies

No evidence of current or past HTLV infection.

Typical UK interpretation:

• HTLV-I/II antibodies: Negative

Positive HTLV-I/II antibodies

Indicates exposure or infection. Confirmatory testing is usually required.

Typical UK interpretation:

• HTLV-I and/or HTLV-II antibodies: Positive

Confirmatory testing required

Reactive screening results are followed by additional tests to confirm infection type.

Results should always be interpreted by a clinician.