Blue-topped (3.2% sodium-citrate) tube.
Routine venipuncture; discard 1st mL of blood by collecting a
discard tube prior to collecting the blue-topped (3.2%
sodium-citrate) tube. For collections with butterfly blood
collection sets, a discard tube should also be collected prior
to collection of the blue top to ensure sufficient sample
volume. Drawing a discard tube will displace the air from the
blood collection set tubing to ensure proper blood draw volume.
Samples should be received in laboratory within ˝ hour of draw
for best results.
clearly mark requisition with type of Heparin (e.g.
Unfractionated, Low Molecular Weight (Lovenox), etc.). Notify
1 hour prior to specimen collection
delivery time is to be greater than
from time of draw,
centrifuge the specimen for 15 minutes at 2000-2500g,
and separate the plasma from the cells.
Transfer plasma to 12x75 plastic tube
Cap tube and re-spin
for 15 minutes at 2000-2500g
remove from centrifuge without disturbing any platelets and/or
cell pellets that might be on the bottom or sides of the tube.
Carefully transfer plasma into freezer tubes (plastic screw-top
cryo-tubes) for testing or freezing. (Note: Testing for
Unfractionated Heparin cannot be done on frozen plasma)
Plasma is stable for 2 hours at
50C. Plasma for testing Low Molecular Weight Heparin
(Lovenox) is stable frozen for 1 week at -20C.
Causes for Rejection:
clotted, severely hemolyzed specimen, plasma specimen greater
than 2 hours old, wrong tube (3.8% sodium citrate), high
hematocrit (> 55%), sample identification error, sample
processed/transported, and/or stored improperly.