Smooth muscle antibodies blood test in Chiswick

What the test measures

Smooth muscle antibodies are autoantibodies directed against actin and related proteins found in smooth muscle, the type of muscle in the walls of blood vessels, the gut and other organs. Their main clinical use is in recognising autoimmune hepatitis, a condition in which the immune system attacks liver cells and causes ongoing inflammation.

Autoimmune hepatitis can occur at any age and is more common in women. It may cause tiredness, discomfort under the right ribs, joint pains or jaundice, but it is sometimes found only because liver enzymes such as ALT are raised on a routine test. Smooth muscle antibodies, often measured with ANA and immunoglobulin levels, help a specialist decide whether this is the likely cause.

The price includes the blood sample at our Chiswick clinic, analysis at the Randox accredited laboratory, a practitioner review of your result and a GP feedback report on request.

Who it is for

• Your ALT or AST has come back raised and viral hepatitis, alcohol and fatty liver have been considered.
• You have yellowing of the skin or eyes, in which case please also see your GP promptly.
• You have another autoimmune condition and abnormal liver tests.
• Your GP or practitioner is working through the causes of persistent liver inflammation.
• You have been treated for autoimmune hepatitis before and your specialist has asked for this test.

Understanding your result

A positive result, particularly at a higher titre and alongside raised liver enzymes, supports autoimmune hepatitis and should be followed up with your GP or a liver specialist. Low positive results can be seen after viral infections and in some healthy people, so context matters. A negative result makes autoimmune hepatitis less likely but does not exclude it, as other antibodies can be involved.

Diagnosis usually involves several blood tests and often a liver biopsy, so this result is a prompt for discussion, not a diagnosis. Autoimmune hepatitis generally responds well to treatment when recognised early.

Preparing for your test

No fasting is needed and you can test at any time of day. Please tell us about recent viral illnesses and all medicines and supplements you take, as some can affect the liver.

Our liver function tests show the enzymes that usually prompt this test, and the Standard Screen gives a broader view. You can also browse every blood test and price in Chiswick.

Questions

How much is a smooth muscle antibody test in Chiswick?

The Smooth Muscle Antibodies test costs £89 at our Chiswick clinic. The price includes the blood sample, accredited laboratory analysis, a practitioner review and a GP feedback report on request.

Does this test check my muscles?

No. Despite the name, it is mainly a liver-related test. It does not assess muscle strength or muscle damage.

How is it different from antimitochondrial antibodies?

Smooth muscle antibodies are linked to autoimmune hepatitis, which affects liver cells. Antimitochondrial antibodies are linked to primary biliary cholangitis, which affects the bile ducts.

Can a viral infection cause a positive result?

Yes. Low levels can appear temporarily after infections such as glandular fever, which is one reason results are read in context.