What I have seen or use has been PVC. Good to erosion. Now the best bet is read your hemo machine fron drain recommendation.

Some ask for a free fall air gap. Since we have gone to hight flux de amout of CR!! that goes down the drain is up. If the machine drain is connected to a smaller or same size you can get growth on the machine drains. Solution we clean the drain at every maintenance. If the drain on the wall is bigger example we have in one unit where the machine drains connects to a 2inch drain pipe with a 1 foot fall(air gap. It took about 8 years before we started getting build up.

The one with small drains or lots of bend need blowing out with hot water every once in a while or we get TMP problem with hemo machines.

In one our new units thyat the drain will not have regular flow we are getting a automatic (or manual) flushing that let water run down the drain every once in a while to reduce smells and growth.