{TAIL ~ a valve seating portion} having a valve opening therein, said valve opening permitting serum or {HEAD ~ plasma} to flow into said tubular member when the separator tube is plunged into the collection tube, 
{ TAIL ~ a valve seating portion } having a valve opening therein , said valve opening permitting serum or { HEAD ~ plasma } to flow into said tubular member when the separator tube is plunged into the collection tube ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH