How to Prepare for a Mono Blood Test

Mononucleosis is caused by the Epstein-Barr virus (EBV). Testing for mono typically involves taking a blood sample or two and examining the sample for two antibodies of EBV. These two antibodies are viral capsid antigen (VCA)-IgM, VCA-IgG and D early antigen (EA-D) which detects a current or recent infection and VCA-IgG and Epstein Barr nuclear antigen (EBNA) which indicates a previous infection.

The Test Process

The site where the blood is to be taken from is cleaned with a cotton swab and antiseptic (germ-killing medicine). Blood is usually taken from a vein on the back of the hand or more commonly the inside of the elbow. The health care provider taking the blood sample will wrap an elastic band around the upper arm to reduce blood flow, increase pressure and make the vein swell. This can be done before or after the blood-drawing site is cleaned.

The health care provider will carefully insert a needle into the enlarged vein. The needle is attached to an airtight tube or vial which collects the blood sample. This usually takes only a few seconds. The elastic band is removed when the tube or vial is almost full. Once enough blood has been collected, the needle is taken out and the provider will use a cotton ball to apply pressure to the puncture site to stop the bleeding. You may be asked to press on the cotton for a minute or two.

The Preparation Process

There's typically little to no preparation necessary for a mono blood test. Sometimes you may need to abstain from certain foods and drinks which may not be difficult to do if you're already feeling very sick. If you're not getting enough fluids, the doctor may suggest you drink a certain amount of water before a scheduled blood test. You may be asked not to take any medications for several hours before the blood work which could skew the results. Do not smoke before a test.

Often a mono blood test isn't scheduled like other blood work is and is done right in the hospital room or in the doctor's office. If this is the case there will be no guidelines for you to follow before the test.

If you're feeling well enough to be reasonably active, your healthcare provider may ask you to relax and take it easy for six to 12 hours after the blood sample has been taken. This will reduce the chance of bruising on the arm or hand where the needle was inserted.