The amount of FXIIa produced relative to the amount produced in a control sample which does not contain the tested substance or which contains a different test substance may be used to indicate {HEAD ~ the relative activity} of {TAIL ~ the tested substance} 
The amount of FXIIa produced relative to the amount produced in a control sample which does not contain the tested substance or which contains a different test substance may be used to indicate { HEAD ~ the relative activity } of { TAIL ~ the tested substance }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL