Blood Collection Tubes

Complete Blood Count (CBC):

EDTA tubes (purple top):
- Purple top tubes should be 50-60% full. Do not overfill tubes.
- Gently mix specimen by inverting 5-10 times and place it on a rocker for up to 30 minutes, then refrigerate at 2-8°C. When a differential is required as part of a CBC, slides must be prepared within 12 hours of blood collection.
- Refrigerated EDTA blood is stable for CBC for up to 24 hours. Clotted or hemolyzed specimens are unacceptable. Check for clots by using a clean wooden applicator stick and gently swirling blood in tube.
- EDTA microtainers must be “shaken” 10-15 times to overcome the surface tension within the tube

Serum Chemistry:

Plain or serum separator tube (red top or SST, red/camouflage top):
- SST tubes should be at least 50-80% full and should be mixed.
- No mixing is necessary with plain tubes.
- Both plain and SST tubes must be allowed to clot at 4°C for 30 minutes - 60 minutes. Then the samples must be centrifuged at 7000rpm for 10 minutes and the serum decanted and frozen at -80°C for clinical chemistry analysis.
Heparin tube (green top – chemistry/blood gas):
- Tubes should be at least 50% full.
- Gently mix specimen by inverting 8-10 times and place immediately on at 4°C for 30 minutes - 60 minutes before spinning in a centrifuge, although the exact time allowable may be protocol specific.

Coagulation:

Sodium citrate tubes (blue top):
- Citrate tubes should be filled to the top.
- Gently mix specimen by inverting at least 5-6 times and place immediately at 4°C for up to 30 minutes before spinning in a centrifuge.

Blood Glucose:

Sodium fluoride tubes (gray top):
- Tubes should be at least 65-80% full.
- Gently mix specimen by inverting 5-6 times and place immediately at 4°C for up to 30 minutes before spinning in a centrifuge
- If blood is placed into tubes after removing the tube tops, care must be taken not to cross contaminate tubes containing anticoagulant. It is best to remove the needle before filling the tubes.

Capillary tubes:

Take capillary tube and place finger on the end of tube that has the blue or red fill line mark on it.
Place other end of the capillary tube into the tip of a blood filled syringe, in a drop of blood on Parafilm, or along the edge of a tube of blood (being careful not to spill it!).
Release finger and allow blood to fill the capillary tube (If possible to the blue or red line) by capillary action. If less blood is available, fill as full as is possible.