There is an order in which the drawing of specimens should be preformed. This is to minimize contamination of subsequent specimens by organisms, anticoagulants, potassium and other materials.

Vacuum Tubes: The order of draw is given the following Table:

Order of Specimen Draw (Vacuum Tubes)

• Sterile Tubes (Blood Culture)
• Blue-top Tubes (Coagulation)
• Red top or Gel-Separator Tubes
• Green-Top Tubes (Heparin)
• Lavender-Top Tubes (EDTA)
• Grey-Top Tubes (Oxalate/Fluoride)

Selected Reference: NCCLS. Procedures For the Collection of Diagnostic Blood Specimens by Venipuncture. Approved Standard H3-A4. Villanova, PA:NCCLS; June 1998.