{HEAD ~ The amount} of {TAIL ~ 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 the relative activity of the tested substance 
of
{ HEAD ~ The amount } of { TAIL ~ 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 the relative activity of the tested substance
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH