Normal results vary based on the method and activators used. Normal APTT results are usually between 25-40 seconds; PTT results are between 60-70 seconds.APTT results for a patient on heparin should be 1.5-2.5 times normal values.An APTT longer than 100 seconds indicates spontaneous bleeding.artial thromboplastin time (PTT), a test for detecting coagulation defects of the intrinsic system by adding activated partial thromboplastin to a sample of test plasma and to a control sample of normal plasma. The time required for the formation of a clot in test plasma is compared with that in the normal plasma.