Lab test · Infection
Anti-Streptolysin O (ASO) Titre
Strep infection, rheumatic fever
- Blood sample
- No fasting
- Report within 24 hours
- Home collection
What this test is for
Strep infection, rheumatic fever
The ASO titre measures antibodies against streptolysin O, a substance made by group A streptococcus, the bacterium that causes strep throat. These antibodies rise in the weeks after an infection, so a raised level shows a recent streptococcal infection even when the throat has already recovered. Doctors mainly use it to help diagnose complications that can follow strep infection, such as rheumatic fever and a kidney inflammation called post-streptococcal glomerulonephritis.
Why a doctor may order it
- Joint pain and fever a few weeks after a sore throat, when rheumatic fever is a concern
- Swelling, dark or bloody urine after a throat or skin infection
- To show a recent strep infection when a throat swab is no longer positive
- As a repeat test to see whether the level is rising or falling
How to prepare
Fasting: Not needed.
No special preparation is needed; eat and drink as usual. Tell your doctor about any recent sore throat or skin infection and whether you have taken antibiotics, as this helps with reading the result.
At home
- Sample
- Blood sample
- How it works
- A collector comes to your home and takes a small blood sample from a vein in the arm. It takes a few minutes. For children, a parent can stay close to help them keep still.
- Report
- Within 24 hours of collection.
What the results can mean
A raised ASO level suggests a recent streptococcal infection. It does not by itself mean rheumatic fever or kidney disease, and many healthy people, especially children, have some ASO in their blood. A rising level on a repeat test is more meaningful than a single value, and a normal level does not rule out every strep infection. Your doctor will interpret the result together with your symptoms and other tests.
What's included
One test: Anti-Streptolysin O (ASO) Titre, from one blood sample.
Related tests
- C-Reactive Protein (CRP), QuantitativeC-reactive protein (CRP) is a protein made by the liver in response to inflammation.
- Erythrocyte Sedimentation Rate (ESR)The ESR measures how quickly red blood cells settle to the bottom of a tall, thin tube over a set time.
- Complete Blood Count (CBC)A complete blood count looks at the three main types of cells in your blood: red blood cells, which carry oxygen; white blood cells, which fight infection; and platelets, which help blood to clot.
- Urine Routine Examination (Urine R/E)A urine routine examination, also called urinalysis, looks at your urine in three ways: its appearance, its chemistry (such as protein, sugar and acidity) and, under a microscope, any cells, crystals or bacteria.
- Rheumatoid Factor (RF)Rheumatoid factor (RF) is an antibody that the immune system can make against the body's own tissues.
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Questions people ask
Does a high ASO titre mean rheumatic fever?
No. A high ASO shows a recent strep infection. Rheumatic fever is diagnosed from a combination of symptoms, examination and tests, and ASO is only one part of that picture.
Why is the ASO test sometimes repeated?
A level that rises between two tests taken some weeks apart is stronger evidence of a recent infection than a single raised result.
Is the ASO test used for joint pain in general?
Only when a doctor suspects the joint pain is linked to a recent strep infection. Other causes of joint pain are checked with different tests, such as rheumatoid factor or anti-CCP.
How much does a ASO titre test cost in Dhaka?
With Mukti Health the price is ৳350, and the sample is collected at your home in Dhaka. You see the price again before you confirm the booking in the Mukti Health app.
Can I do the ASO titre test at home in Dhaka?
Yes. Book it in the Mukti Health app and a trained sample collector comes to your home in Dhaka to take the blood sample. You do not need to go to a laboratory.
How long does the ASO titre report take?
The report is usually ready within 24 hours of the sample being collected.