What is the correct order of draw for evacuated tubes (including blood culture) in a single venipuncture sequence?

What is the correct order of draw for evacuated tubes (including blood culture) in a single venipuncture sequence?

• A. Blood culture bottles first, then light blue, then serum tubes (red or gold SST), then green, then lavender, then gray
• B. Light blue citrate tubes first, then blood culture bottles, then serum tubes, then others
• C. Blood culture bottles first, then red or gold SST, then light blue, then green, then lavender, then gray
• D. Blood culture bottles first, then green tubes, then lavender, then light blue, then serum tubes, then gray

Answer: (A)

The main idea is to prevent additive carryover and contamination from one tube to the next, especially to protect the blood culture specimen. Drawing blood culture bottles first minimizes the risk that skin flora or additives from later tubes will contaminate the culture or interfere with microbial growth, which is critical for accurate detection of pathogens. After blood cultures, the light-blue citrate tubes come next because citrate is a precise anticoagulant used for coagulation studies; drawing them earlier helps prevent any carryover from other additives that could skew clotting results. Serum tubes (red or gold SST) are then collected, since they produce serum and have clot activators or gel separators, and placing them after the citrate reduces potential cross-contamination affecting clotting and serum chemistry tests. Next are the green tubes containing heparin, used for various chemistry tests, followed by lavender tubes with EDTA for hematology; drawing EDTA later helps protect tests that rely on intact calcium and proper cell morphology from interference by other additives. Finally, gray tubes with fluoride/oxalate are drawn last to minimize any glycolysis inhibitor's effect on other tests and to reduce the chance of carryover affecting results. Other sequences can risk contaminating the culture or altering test results through additive carryover, which is why the shown order is preferred.

The main idea is to prevent additive carryover and contamination from one tube to the next, especially to protect the blood culture specimen. Drawing blood culture bottles first minimizes the risk that skin flora or additives from later tubes will contaminate the culture or interfere with microbial growth, which is critical for accurate detection of pathogens.

After blood cultures, the light-blue citrate tubes come next because citrate is a precise anticoagulant used for coagulation studies; drawing them earlier helps prevent any carryover from other additives that could skew clotting results. Serum tubes (red or gold SST) are then collected, since they produce serum and have clot activators or gel separators, and placing them after the citrate reduces potential cross-contamination affecting clotting and serum chemistry tests. Next are the green tubes containing heparin, used for various chemistry tests, followed by lavender tubes with EDTA for hematology; drawing EDTA later helps protect tests that rely on intact calcium and proper cell morphology from interference by other additives. Finally, gray tubes with fluoride/oxalate are drawn last to minimize any glycolysis inhibitor's effect on other tests and to reduce the chance of carryover affecting results.

Other sequences can risk contaminating the culture or altering test results through additive carryover, which is why the shown order is preferred.