What are mononucleosis (mono) tests?

Mononucleosis (mono) is an infectious disease caused by viruses, including:

• Epstein-Barr virus (EBV), which is the most common cause
• Cytomegalovirus
• Toxoplasmosis
• HIV
• Rubella
• Hepatitis A, B, C
• Adenovirus

These viruses are commonly spread through body fluids. Mono is sometimes called the kissing disease because it is spread through saliva. So, besides kissing, you can get it if you share a fork, spoon, drinking glass, straw, food, toothbrush, or lip balm with a person who has mono. These viruses can also spread through blood and semen during sexual contact, blood transfusions, and organ transplants.

EBV is a type of herpes virus that is very common. Most people get infected with EBV at some point in their lives, but only some of them will get symptoms of mono.

Many people become infected with EBV in childhood. EBV infections in children usually do not cause symptoms. But when they do, it's difficult to tell the difference between the symptoms of mono and the symptoms of other childhood illnesses such as the flu.

Teens and young adults, though, are more likely to get mono. In fact, at least one out of four teens and young adults who get EBV will develop mono. They are also more likely to have symptoms that are typical of mono, such as:

• Extreme fatigue
• Fever
• Sore throat
• Swollen lymph nodes in the neck
• Enlarged spleen
• Swollen liver
• Rash

Mono is rarely serious, but symptoms can linger for weeks or months.

Mono is typically diagnosed based on your symptoms. However, in some cases, specific lab tests may be needed to identify the cause of illness. An example would be if someone is having severe or life-threatening illness.

Types of mono tests include:

• Monospot test. This test looks for specific antibodies in the blood. These antibodies show up during or after certain infections, including mono.
• EBV antibody test. This test looks for EBV antibodies, the main cause of mono. There are different types of EBV antibodies. If certain types of antibodies are found, it may mean you were infected recently. Other types of EBV antibodies may mean you were infected in the past.

Other names: monospot test, mononuclear heterophile test, heterophile antibody test, EBV antibody test, Epstein-Barr virus antibody test, mononucleosis spot test

What are they used for?

Mono tests are used to help diagnose a mono infection. Your provider may use a monospot to get fast results. Results are usually ready within an hour. But this test has a high rate of false negatives. This means your test shows you don't have mono, but you actually do have it. So, your provider may also order an EVB antibody test and other tests that look for infections. These include:

• Complete blood count and/or blood smear, which checks for high levels of white blood cells, a sign of infection.
• Throat culture, to check for strep throat, which has similar symptoms to mono. Strep throat is a bacterial infection treated with antibiotics. Antibiotics don't work on viral infections like mono.

Why do I need a mono test?

Your provider may order one or more mono tests if you or your child has symptoms of mono. Symptoms include:

• Fever
• Sore throat
• Swollen glands, especially in the neck and/or armpits
• Fatigue
• Headache
• Rash
• Enlarged liver, spleen, or both
• Swollen tonsils

An enlarged spleen and a swollen liver are less common symptoms. For some people, their liver or spleen, or both, may still be enlarged even after their fatigue ends.

Most people get better in two to four weeks; however, some people may feel fatigued for several more weeks. Occasionally, the symptoms of mono can last for six months or longer.

What happens during a mono test?

You will need to provide a sample of blood from your fingertip or a vein.

For a fingertip blood test, a health care professional will prick your middle or ring finger with a small needle. After wiping away the first drop of blood, he or she will place a little tube on your finger and collect a small amount of blood. You may feel a pinch when the needle pricks your finger.

For a blood test from a vein, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out.

Both types of tests are quick, usually taking less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a fingertip blood test or blood test from a vein.

Are there any risks to mono tests?

There is very little risk to having a fingertip blood test or blood test from a vein. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If your monospot test result is positive, it may mean you or your child has mono. If it is negative, but you or your child still have symptoms, your provider will probably order an EBV antibody test.

If the monospot test is negative, but you or your child still have symptoms, your provider will probably order an EBV antibody test.

If your EBV test is negative, it means you don't currently have an EBV infection and were never infected with the virus. A negative result means your symptoms are probably caused by another disorder.

If your EBV test is positive, it means EBV antibodies were found in your blood. The test will also show which types of antibodies were found. This allows your provider to find out whether you were infected recently or in the past.

While there is no cure for mono, you can take steps to relieve symptoms. These include:

• Get plenty of rest
• Drink lots of fluids
• Suck on lozenges to soothe a sore throat
• Take over-the-counter medicines for pain and fever. But don't give aspirin to children or teens because it may cause Reye syndrome, a serious, sometimes fatal, disease that affects the brain and liver.

Antibiotics are not used to treat mono. If you have a bacterial infection along with mono, you should not take penicillin antibiotics like ampicillin or amoxicillin. Otherwise, you may experience a reaction, such as a rash. If you have severe symptoms, your provider may suggest additional treatment based on which organs in your body are affected by the mono. Mono usually goes away on its own within a few weeks. Fatigue may last a bit longer.

Mono can cause an enlarged spleen, which could rupture and cause a medical emergency. To try to protect the spleen, providers recommend avoiding intense exercise and contact sports until you fully recover (about a month). If you have questions about your results or treatment for mono, talk to your provider.

Learn more about laboratory tests, reference ranges, and understanding results.