meperidine in system

I will be getting my drug test soon and I already have fentanyl which they know about but ive been doing a little meperidine now and then how long should I discontinue its usage prior to drug test to be clear of it
or will the test even know what types of opiates are in me

 

meperidine lasts 4-24 hours in your body.
To be very safe, give yourself double that time. Shouldn't be too hard.