Tube Handling Procedures

Red Top Tubes

  • Red top tubes contain no additives. Red top tubes must be allowed to clot completely (30-60 minutes) prior to centrifugation. Centrifuging the specimen yields serum.

  • NOTE: All drug levels must be drawn in red top tubes only.

Serum Separator Tubes (Gold Top)

  • Serum separator tubes contain a clot activator and a separation gel. Tubes should be inverted 5 times to expose blood to the clot activator.

  • To produce a solid separation barrier, allow the blood to clot in an upright position for at least 30 minutes, but no longer than 1 hour before centrifugation.

  • Transfer of serum to a plastic vial is not necessary for specimens drawn in serum separator tubes.

Sodium Citrate Tubes/Coagulation (Light Blue Top)

  • Light Blue top tubes contain the anticoagulant buffered sodium citrate.

  • Centrifugation provides plasma used for coagulation tests. See specific test requirements in the NLL Directory of Services.

  • Gently invert the tube 3 to 4 times immediately after collection.

  • NOTE: Light Blue top tubes must be allowed to fill completely; the ratio of blood to anticoagulant is critical. Under filled tubes will be rejected.

Sodium Heparin Tubes (Dark Green Top)

  • Dark Green top tubes contain the anticoagulant heparin combined with sodium.

  • Gently invert the tube 8 to 10 times immediately after collection to ensure proper mixing with the anticoagulant.

EDTA Tubes (Lavender Top)

  • Lavender top tubes contain the anticoagulant potassium EDTA.

  • Lavender top tubes must be adequately filled to ensure the correct blood to anticoagulant ratio.

  • Gently invert the tube 8 to 10 times immediately after collection to ensure proper mixing with the anticoagulant.

K2 EDTA (Dark Blue Top)

  • Dark Blue EDTA tubes are used for whole blood trace element analysis.

  • Gently invert the tube 6 to 8 times immediately after collection to ensure proper mixing with the anticoagulant.

Dark Blue Top (No Additive)

  • Dark Blue No Additive tubes are used for serum trace element analysis.

  • Blood must be allowed to clot for at least 30 minutes before centrifugation. Remove serum and place in a transport tube.