Which position in the evacuated tube system should green and tan tubes be collected?

• A. Draw 5
• B. Draw 2
• C. Draw 7
• D. Draw 9

Answer: (A)

The position of each tube in the evacuated tube order is about preventing additive carryover between tubes. Green tubes contain lithium heparin for plasma tests, and tan tubes are used for lead testing and have a different additive. Placing both in the fifth position follows the lab’s validated sequence so these tubes are drawn at a point where their additives won’t contaminate or be contaminated by the surrounding tubes’ contents, helping preserve the accuracy of the tests that rely on those additives. Drawing them earlier or later could increase the risk of carryover affecting subsequent samples, leading to inaccurate results.