Antistreptolysin Titre (ASOT)
This test measures antibodies to streptococcal bacteria. It helps identify recent infection and related inflammatory complications.
Turnaround time
1-2 days
Biomarkers count
1
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Details about Antistreptolysin Titre (ASOT)
ASOT Blood Test | London Blood Tests |
Detect recent streptococcal infection with the Antistreptolysin O Titre (ASOT) blood test for £88. UKAS-accredited testing, GP review optional.
The Antistreptolysin O Titre (ASOT) Blood Test measures antibodies produced in response to Group A Streptococcusinfection. It is commonly used to investigate recent or past streptococcal infections and related complications such as rheumatic fever and post-streptococcal glomerulonephritis. Testing is performed in a UKAS-accredited laboratory, with an optional GP consultation.
What is an Antistreptolysin O Titre (ASOT) Test?
Antistreptolysin O (ASO) is an antibody produced by the immune system following infection with Group A beta-haemolytic Streptococcus, the bacteria responsible for conditions such as strep throat, scarlet fever, and skin infections.
ASOT testing does not detect the bacteria itself, but rather the immune response to it. Antibody levels typically rise 1–3 weeks after infection, peak at around 3–5 weeks, and then gradually decline over several months.
The ASOT test is particularly useful when complications are suspected after a streptococcal infection has resolved, helping clinicians confirm recent exposure.
At London Blood Tests, ASOT is measured using validated immunoassay techniques aligned with UK infectious disease standards.
Benefits of the ASOT Test
- Confirms Recent Streptococcal Infection
Detects immune response even after symptoms have resolved. - Supports Diagnosis of Post-Strep Complications
Essential for investigating rheumatic fever and kidney inflammation. - Useful When Swab Tests Are Negative
Helps confirm infection retrospectively. - Assists Autoimmune & Inflammatory Investigations
Identifies streptococcal triggers for immune-mediated conditions. - Non-Invasive & Simple
Requires only a standard blood sample. - Clinically Relevant for Children and Adults
Used in both paediatric and adult medicine. - Optional GP Consultation for Interpretation
Results can be reviewed with a GP to guide further testing.
Why Do I Need an ASOT Blood Test?
You may benefit from an ASOT test if you have symptoms or conditions that may follow a streptococcal infection, including:
- Persistent joint pain or swelling
- Fever with no clear cause
- Skin rashes
- Blood or protein in urine
- Fatigue following a recent sore throat
- Suspected rheumatic fever
Testing is commonly recommended if:
- Symptoms appear weeks after a throat or skin infection
- Streptococcal infection was suspected but not confirmed
- There is concern about immune-related complications
Because streptococcal complications can be serious, early confirmation supports prompt management.
How the Test Works
In-Clinic Testing at London Blood Tests
- Book Your Appointment
- Book online or by phone at your chosen clinic.
- No fasting required.
- Pre-Test Review
- Inform the clinician about recent sore throat, fever, or skin infection.
- Sample Collection
- A trained phlebotomist collects a venous blood sample.
- Takes 5–10 minutes.
- Laboratory Analysis
- Sample analysed in a UKAS-accredited laboratory.
- Quality Control
- Results verified before release.
- Results Delivery
- Results typically available within 5–10 business days.
- Optional GP Consultation
- Review results and clinical implications with a GP.
At-Home Blood Draw (Home or Hotel Phlebotomy – UK-Wide)
- Book Your Visit
- Arrange a phlebotomist home or hotel visit.
- Professional Collection
- Certified phlebotomist collects your blood sample.
- Secure Transport
- Sample couriered same day to the laboratory.
- Laboratory Testing
- Analysis identical to clinic testing.
- Results & Follow-Up
- Results delivered online, GP review optional.
Your ASOT Test Results – Explained
ASOT results are reported in IU/mL.
Typical UK reference guidance:
- Adults: < 200 IU/mL
- Children: < 150 IU/mL (may vary by age)
Interpretation:
- Normal ASOT: no recent streptococcal infection
- Raised ASOT: recent or past streptococcal infection
- Very high or rising titres: suggest recent infection or ongoing immune response
Sometimes, paired samples taken weeks apart are used to confirm rising titres.
How It Works
Simple steps to get your results
Book Online
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
Take control of your health with London Blood Tests
WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.