In the order of draw for blood specimen collection, which color tube is drawn first?

• A. Light Blue
• B. Red
• C. Green
• D. Yellow

Answer: (D)

Drawing the first tube with a sterile culture tube (yellow top) is done to protect the culture results from contamination and additive carryover. Yellow tubes are specifically designed for blood cultures and must be collected first so skin flora or residues from other tubes don’t contaminate the culture specimen. This preserves the accuracy of culture growth if bacteria are present in the blood. After the culture tube, other tubes with anticoagulants or clot activators are drawn in the established sequence to minimize interference with the culture and with subsequent tests.