Heparin drip drawing peripheral PTT

What is the appropriate way to draw a PTT if you have a patient with multiple DVTs to the right upper extremity with right arm restrictions and a heparin drip to the left forearm peripherally? Do you stop the infusion and flush with NS and then draw distal from the IV? Is it okay to draw distal from the IV if the drip is infusing? Will drawing a PTT be more accurate if you stop the heparin and then draw...or is you don't stop the infusion and draw distally from the IV?
too many questions for a 2-point poll. yes, you can draw from a vein distal to the infusing iv. the test is looking at what the patient's state is at when the med is being given. there is no reason to turn off the infusion while you draw; if you are drawing distally you are not sampling the running iv fluid. i would not draw through the line if only because you have fewer options if you compromise it since the other arm is off-limits.

Quote from grnteatoo many questions for a 2-point poll. yes, you can draw from a vein distal to the infusing iv. the test is looking at what the patient's state is at when the med is being given. there is no reason to turn off the infusion while you draw; if you are drawing distally you are not sampling the running iv fluid. i would not draw through the line if only because you have fewer options if you compromise it since the other arm is off-limits.