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Mono Spot Test

What Is Mononucleosis?

Infectious mononucleosis is a viral infection. It is commonly known as mono.

Reason for the Test

The test is needed if the doctor suspects a person has mono. Antibodies are proteins found in blood or other bodily fluids. The immune system makes antibodies to fight the virus. The test detects levels of certain antibodies that point to mono.

Type of Sample Taken

A blood sample will be taken from the arm.

Prior to Collecting the Sample

Nothing needs to be done before blood is taken. Talk to your doctor about your health. Some conditions can lead to a false positive test .

During the Sample Collection

You will be asked to sit. An area inside your elbow will be cleaned with a wipe. A large band will be tied around your arm. The needle will be put in a vein. A tube will collect the blood from the needle. The band on your arm will be taken off. After the blood is collected, the needle will be removed. Gauze will be held on the site to help stop bleeding. You may also be given a bandage. This test takes about 5 to 10 minutes.

After Collecting the Sample

After the blood sample is taken, you may need to stay seated for 10 to 15 minutes. If you are lightheaded, you may need to stay seated longer. When you feel better, you can leave.

A bit of blood may ooze from the vein beneath the skin. It will cause a bruise. A bruise will usually fade in a day or two.

Call your doctor right away if you have redness, swelling, lasting bleeding, or pain.


Results can take 24 hours to several days. It depends on the lab.

Test results may not be correct based on the timing. Another test may be needed in a week.

By 2 weeks, antibodies show up in nearly half of people with mono. By 4 weeks, most mono infections can be found with the mono spot test. The test can stay positive for up to 3 months after the infection has passed.

Talk to your doctor about your test results. A test may point to an illness that you do not have. It can also miss an illness that you may have. The doctor will check your symptoms and all test results before making a diagnosis


Epstein-Barr virus-associated mononucleosis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/epstein-barr-virus-associated-infectious-mononucleosis. Accessed August 20, 2021.

Mononucleosis (mono). Family Doctor—Academy of Family Physicians website. Available at: https://familydoctor.org/condition/mononucleosis. . Accessed August 20, 2021.

Mononucleosis (mono) test. Lab Tests Online website. Available at: https://labtestsonline.org/tests/mononucleosis-mono-test. Accessed August 20, 2021.

Last reviewed July 2021 by EBSCO Medical Review Board David L. Horn, MD, FACP  Last Updated: 8/20/2021