Definition

What is anti-Jo-1 antibodies test?

Anti-Jo-1 antibodies test is a test in order to measure Anti-Jo-1 antibodies in your blood. Jo-1 (histidyl tRNA synthetase) is a member of the amino acyl-tRNA synthetase family of enzymes found in all nucleated cells. Jo 1 antibodies in patients with polymyositis bind to conformational epitopes of the enzyme protein and inhibit its catalytic activity in vitro.

Jo 1 antibodies are a marker for the disease polymyositis, and occur most commonly in myositis patients who also have interstitial lung disease. The antibodies occur in up to 50% of patients with interstitial pulmonary fibrosis and symmetrical polyarthritis.

Why is anti-Jo-1 antibodies test performed?

There are a couple of reasons why the anti-Jo-1 antibodies test may be done in order to evaluate patients with signs and symptoms compatible with a connective tissue disease, especially those patients with muscle pain and limb weakness, concomitant pulmonary signs and symptoms, Raynaud’s phenomenon, and arthritis.

Precaution/Warnings

What should I know before receiving anti-Jo-1 antibodies test?

There are some recommended preparations you may be required for an anti-Jo-1 antibodies test:

  • Do not drink alcohol for 24 hours before the test.
  • For a blood test, do not eat or drink anything except water for at least 2 hours before having the test.
  • Many medicines may affect the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.

Testing for antibodies to Jo 1 is not useful in patients with a negative test for antinuclear antibodies.

A negative test for Jo 1 antibodies does not exclude the diagnosis of polymyositis or dermatomyositis

Process

How to prepare for anti-Jo-1 antibodies test?

It is advisable that there are a great number of things that need preparing before the test, including:

In blood test

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Hook a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure on the site and then put on a bandage.

In urine test

Anti-Jo-1 antibodies test can be measured by two ways, in a 24-hour or 2-hour urine sample.

A 24-hour urine sample is all of the urine you produce over a 24-hour period.

  • You start collecting your urine in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.
  • For the next 24 hours, collect all your urine. Your doctor or lab will usually provide you with a large container that holds about 1 gal (4 L). The container has a small amount of preservative in it. Urinate into a small, clean container and then pour the urine into the large container. Do not touch the inside of the container with your fingers.
  • Keep the large container in the refrigerator for the 24 hours.
  • Empty your bladder for the final time at or just before the end of the 24-hour period. Add this urine to the large container and record the time.
  • Do not get toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.

A 2-hour urine sample is all of the urine you produce over a 2-hour period. Collect it in the same manner as the 24-hour urine sample, during the 2-hour period your health professional recommends.

What happens during anti-Jo-1 antibodies test?

During this test, you may undergo:

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. Therefore, it may feel tight and uncomfortable. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

There is no pain while collecting a 2-hour or 24-hour urine sample.

What happens after anti-Jo-1 antibodies test?

Very little chance of a problem from having a blood sample taken from a vein can occur.

Firstly, you may get a small bruise at the site. However, you can lower the chance of bruising by keeping pressure on the site for several minutes.

In some rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. You should use a warm compress several times a day to solve this situation

Moreover, ongoing bleeding can be a problem for some patients with bleeding disorders. Some medications such as aspirin, warfarin (Coumadin), and other blood-thinning medicines are able to make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

If you have any questions about the anti-Jo-1 antibodies test, please consult with your doctor to better understand your instructions.

Explanation of results

What do my results mean?

Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. Generally, the normal level of anti-Jo-1 antibody is under 1.0 U. It means when your result is over 1.0 U, it is considered as abnormal.

Please discuss with your doctor any questions you may have about your test results.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: September 8, 2017 | Last Modified: September 8, 2017

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