Why would your doctor order a PTT test?
PTT tests analyze proteins and other factors involved in the blood clotting process known as the coagulation cascade, explains MedlinePlus. To get more accurate results, doctors may ask patients to stop taking aspirin, vitamin C, antihistamines and other medications that can affect the readings. Results may vary among labs due to different measurement techniques. Depending on the results and an evaluation of a patient's overall health, doctors may adjust dosages of blood thinning medications such as heparin, notes WebMD.
Sources: webmd.com, webmd.com, nlm.nih.gov