realizes is about has_specified_input has_specified_output role of has role blood coagulation time measurement datum evaluant role assay blood specimen activated partial thromboplastin time assay Alan Ruttenberg An assay that evaluates blood coagulation by measuring the time required for the appearance of fibrin strands following the mixing blood or plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of blood coaguation . It is used as a screening test and to monitor heparin therapy. OBI call The activated partial thromboplastin time (aPTT) was determined using Dade Actin FSL activated PTT reagent (PMID:19696660) There is also the 'partial thromboplastin assay', which some people use synonymously to aPPT, but historically was done slightly differently (without adding a coagulant). aPTT assay url:http://www.ebi.ac.uk/ols/ontologies/efo/terms?short_form=EFO_0004310 activated partial thromboplastin time assay blood plasma specimen metadata complete