[font="comic sans ms"]depends on the picc.
with some piccs, each lumen is exactly the same. same gauge, lumens exit at the same place. (this type seems to be more common to me, but it just could be the part of the country i am in)
with other piccs, the lumen size varies, and/or the lumens may "exit" the picc at different points (like a triple lumen), giving you a proximal and distal port. arrow makes this type of picc catheter.
in the first case, the blood can be drawn from either port, as they are equal.
in the second case, the blood should be drawn from the largest port, and/or the most distal port. however, it can be drawn from either port, just like a triple lumen (blood should be drawn from the 16g distal port, but really can be drawn from any port, unless facility policy states otherwise), if both ports are large enough.
tradition dictates that blood is drawn from the brown port, but that is more tradition than an absolute. as a previous poster stated, you shouldn't draw a drug level out of the same lumen a drug is infused from (don't draw a vanc trough from a line you infuse vanc through). color-coding the ports is helpful for this; you draw the drug levels from the brown port and infuse the drugs through the white port. however, this only works if everyone is on the same page.