Light blue tubes correspond to which draw in the order of draw?

Light blue tubes correspond to which draw in the order of draw?

• A. 1st draw
• B. 2nd draw
• C. 3rd draw
• D. 4th draw

Answer: (B)

Light blue tubes are used for coagulation testing and contain 3.2% sodium citrate, an anticoagulant that binds calcium to prevent clotting. Because tests like PT/INR and aPTT require a precise blood-to-anticoagulant ratio, and to avoid cross-contamination of additives into other tubes, these tubes are drawn after the blood culture bottles but before other additive-containing tubes. That placement keeps the citrate sample uncontaminated and ensures accurate test results. Also, these tubes must be filled to the correct volume to maintain the proper ratio; underfilling can invalidate coagulation results.

Light blue tubes are used for coagulation testing and contain 3.2% sodium citrate, an anticoagulant that binds calcium to prevent clotting. Because tests like PT/INR and aPTT require a precise blood-to-anticoagulant ratio, and to avoid cross-contamination of additives into other tubes, these tubes are drawn after the blood culture bottles but before other additive-containing tubes. That placement keeps the citrate sample uncontaminated and ensures accurate test results. Also, these tubes must be filled to the correct volume to maintain the proper ratio; underfilling can invalidate coagulation results.