The reaction occurs quickly , and involves {HEAD ~ the addition} of {TAIL ~ only one reagent} to a diluted serum specimen 
of
The reaction occurs quickly , and involves { HEAD ~ the addition } of { TAIL ~ only one reagent } to a diluted serum specimen
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH