Initiation may be achieved by adding a blood coagulation factor {HEAD ~ XII activator} to {TAIL ~ animal plasma} in the presence of the test substance 
to
Initiation may be achieved by adding a blood coagulation factor { HEAD ~ XII activator } to { TAIL ~ animal plasma } in the presence of the test substance
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH