Human T-lymphotropic virus type I/II antibody screen (serum/plasma)
This test detects antibodies to two related viruses that can cause chronic infections and rare blood disorders. It helps identify if your immune system has encountered these viruses.
["A simple blood test to check for antibodies linked to rare but serious conditions."]
Key facts at a glance
- LOINC
- 42340-0
- Short code
- HTLV I p42 Ab Ser Ql IB
- Synonyms
- HTLV I p42 Ab Ser Ql IB
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ib
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
This blood test checks for antibodies to human T-lymphotropic virus (HTLV), a virus that can affect the immune system and has been linked to certain rare diseases. Finding these antibodies in your blood means your body has been exposed to HTLV type 1 or type 2 at some point.
The test looks for antibodies against Human T-lymphotropic virus (HTLV-1 and HTLV-2). Antibodies are proteins your immune system makes in response to a virus. If present, they suggest past or current infection, though not everyone infected will test positive.
Your doctor may recommend this test if you have possible risk factors for HTLV, such as a partner who carries the virus, a history of injecting drugs, or a past blood transfusion or organ transplant. It is also used to screen donated blood, breast milk, and organs before they are given to someone else.
Doctors may order this test if you have symptoms like fatigue, rash, or unexplained muscle/joint pain, or if you’re at higher risk (e.g., living in areas with HTLV prevalence, having unprotected sex, or receiving blood products before 1985).
A small blood sample is drawn from a vein, usually on the inside of your elbow. The laboratory screens the sample for HTLV antibodies, and if that first screening comes back reactive, a second, more specific confirmatory test is run before any results are reported to your provider.
A small blood sample is taken and tested using an immunoassay method to detect antibodies. Results are qualitative (positive/negative) rather than measuring exact antibody levels.
The blood draw itself takes only a few minutes. You may feel a quick pinch or sting when the needle goes in, and the site may be slightly sore or bruised afterward. Most results are ready within a few days to about a week, and your provider will review the findings with you.
You’ll have a quick, minor blood draw. Results are usually ready within days. If positive, further testing (like confirmation) may be needed to rule out false positives.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
HTLV-1/2 Antibody Screen
Frequently asked questions
If positive, HTLV infection can lead to diseases like HTLV-associated myelopathy (HAM), tropical spastic paraparesis, or adult T-cell leukemia. Early detection helps monitor symptoms and manage care.
A positive result means your blood contains antibodies to HTLV-1 or HTLV-2, indicating past or current infection. This doesn’t always mean you’ll develop serious illness, but it warrants further evaluation by your doctor.
No, HTLV spreads mainly through blood transfusions (rarely), sexual contact, mother-to-child birth, or sharing needles. Casual contact (like hugs or sharing food) doesn’t transmit it.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy