The monospot blood test is used to determine if someone has infectious mononucleosis. This test is usually ordered as part of a panel that is called the complete blood count. The goal is to determine if there are more white blood cells than there should be. A measurement of reactive lympocytes is also part of this test. In short, the monospot blood test looks to see if there are more white blood cells of different types than there should be.
A monospot blood test can come back as normal, but the disease can still be present. Because the test looks for heterophile antibodies that have developed in the presence of the infectious mononucleosis, a suspicion of the disease and a negative test result may have a doctor order a second test 7 days later to completely rule out the possibility of mononucleosis. This is because the antibodies can take longer to develop in some people than others for an unknown reason.
If the monospot blood test continues to be negative, then the next step in the diagnostic process would be to screen for an EBV infection. Sometimes a strep test is also ordered to rule out the possibility of a Group A or Group B streptococcal infection instead of mononucleosis is there is a sore throat.
When Will a Doctor Order the Monospot Blood Test
It is more common to have this test ordered for teens and young adults because of their higher risks of exposure to infectious mononucleosis. If there are symptoms that mimic the cold or flu but seem to get worse instead of better, then it would be time to discuss this test with a doctor. Symptoms that would prompt the order for this blood test include swollen glands in the neck or armpit, ongoing fatigue, fever, an enlarged liver, or a rash that won’t go away.
What if the test is positive? A positive monospot blood test generally means that someone has an active case of infectious mononucleosis. This is a rapid test that will generally produce same day results. There are no specific guidelines to follow for the general population, although a doctor may order instructions for the test based on a specific medical history.
In rare circumstances, the monospot test can also come back as positive with the presence of lupus, lymphoma, or prostate cancer even when mononucleosis is not present.
What if the test is negative? Infectious mononucleosis can still be present if this test comes back as negative. Younger children and infant will always be negative for this test because their bodies don’t make the heterophile antibodies that are measured. If mononucleosis is not suspected and strep throat has been ruled out, then there may be another micro-organism infection present, such as toxoplasmosis or CMV.
How Serious Is Infectious Mononucleosis?
If infectious mononucleosis is the diagnosis from a positive blood test, then most people will receive supportive treatments that include extra fluids and rest. It may take up to 4 months for the body to fight off the infection and sometimes limited activities are required because the disease can cause the liver to swell. The spleen may also be affected. Only in rare instances when the heart or central nervous system are affected will more serious health issues arise.
For men who have a specific XLP gene, the diagnosis of infectious mononucleosis is quite dangerous and could be life threatening. Be sure to speak with your doctor immediately if you have the XLP gene and the monospot blood test comes back as positive.
EBV will stay within the body throughout a person’s life once an infection occurs. It may stay in remission and never activate again or it may activate after just 30-60 days after the symptoms of mononucleosis subside. Most relapses are symptom-free. If symptoms do occur, the same treatment profile is generally used.
EBV has been linked to certain serious illnesses, including cancer. This is only in rare circumstances and never as a direct encounter with infectious mononucleosis. If you are diagnosed with mononucleosis, your chances of developing cancer later on in life are the same as the general population rates.
The monospot blood test is generally not going to find a life threatening condition. It is usually used to confirm the presence of mononucleosis and nothing more. Most people will receive a negative test result when healthy. Keep these results in mind as you await your test results and put your mind at ease.