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