A separator tube adapted to be pushed into a collection tube containing {TAIL ~ blood} for separating {HEAD ~ serum} or plasma from the formed elements of the blood, said separator tube comprising: 
A separator tube adapted to be pushed into a collection tube containing { TAIL ~ blood } for separating { HEAD ~ serum } or plasma from the formed elements of the blood , said separator tube comprising :
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH