What is the standard order of draw for blood collection tubes?

• A. Yellow, Light Blue, Red, Gold, Tiger Top, Red/Yellow/Black, Green, Light Green, Green/Gray, Purple/Lavender, Pink, Gray, Royal Blue, Tan
• B. Yellow, Light Blue, Red, Gold, Green, Light Green, Purple/Lavender, Pink, Gray, Royal Blue, Tan
• C. Yellow, Red, Light Blue, Gold, Tiger Top, Green, Light Green, Purple/Lavender, Pink, Gray, Royal Blue, Tan
• D. Yellow, Light Blue, Red, Green, Gold, Red/Yellow/Black, Purple/Lavender, Pink, Gray, Royal Blue, Tan

Answer: (A)

The key idea is to prevent additive carryover and preserve test accuracy. Different tube types contain different additives that can alter blood components or interfere with tests if they contaminate later samples. Starting with the yellow sterile tube keeps any potential culture contaminants from affecting other tests. Following with a light blue citrate tube protects coagulation studies from other additives that could change clotting. Then tubes with no additive or clot activator (red, then gold/tiger top) let blood clot and yield serum without interference, which is important for many chemistry panels. After serum tubes, tubes that use heparin (green, and the pale green PST) are drawn to obtain plasma for assays without clotting. EDTA tubes (purple/lavender and pink) come next, since EDTA preserves cellular components for hematology and blood banking tests, and should not contaminate serum or plasma tests. The gray tube with glycolytic inhibitors is placed after EDTA to preserve glucose while not affecting prior tests. Finally, tubes intended for trace elements or special tests (royal blue) and tan for lead are collected last to minimize element contamination of other samples. This ordering helps ensure each test receives the correct sample type without cross-contamination.