When you take a medicine (or drug), your body needs to find a way to use it.  Some proteins in your body break down (or metabolize) medicines.  Breaking down a medicine can make it more active or less active, based on what kind of medicine you are taking.  If your body breaks down a medicine too quickly or too slowly, this may make the medicine not work as well.  It may also cause a side effect.

The DPYD gene gives instructions to your body to make the DPD protein.  It is the job of the DPD protein to break down certain medicines.  These medicines include some anticancer treatments, called fluoropyrimidines.  Examples of these medicines are:

• Capecitabine
• Fluorouracil (5-FU)

These are the medicines that we know of right now that are impacted by DPYD gene test results.  Medical experts keep finding new data about which medicines are affected by gene test results. 

By testing your DNA, we can find DNA differences.  This can help us to see how well the proteins in your body work to break down certain medicines. 

The results of your DPYD gene test put you into 1 of 3 groups:

• Normal metabolizer: People in this group are likely to have normal working DPD proteins.
• Intermediate metabolizer: People in this group may have reduced function of DPD proteins. 
• Poor metabolizer: People in this group may have very little or no active DPD protein. 

The results of this test can help your doctor choose the right medicine and dose for you.