phlebotomy
Order of Draw (Phlebotomy Tubes)
The order of draw is the sequence in which you fill tubes during one venipuncture so that additive from one tube does not carry over into the next and change a result.
11 steps5 criticalLimit 3 minAlways tested
Steps
- 1Critical stepIdentify the tests ordered and the tubes needed, and check tube colors against your laboratory's list
- 2Critical stepFill the blood culture bottle or tube first
- 3Critical stepFill the sodium citrate tube (light blue) next, and fill it completely
- 4Fill serum tubes next, including those with clot activator or gel (red, red-speckled, gold)
- 5Critical stepFill heparin tubes next, with or without gel (green)
- 6Fill EDTA tubes next, with or without gel (lavender, pearl, pink)
- 7Fill the sodium fluoride/potassium oxalate tube (gray) last in this list
- 8For any tube not on this list, ask whether its additive could alter the next tube's result and check with your lab
- 9Check that each tube fills as required; citrate and fluoride/oxalate tubes need a full draw
- 10Critical stepGently invert additive tubes the number of times your lab specifies; do not shake
- 11Label each tube in the patient's presence before leaving
What graders are watching for
Tips
- Memory aid: culture, light blue, red or gold, green, lavender, gray. Check it against your lab's list, since colors can differ.
- The order exists to prevent additive carryover from one tube into the next. It is the same whether you use a syringe, a tube holder, or pre-evacuated tubes (CLSI).
- Tube colors and additives vary, so verify recommendations with your local laboratory (WHO).
Common mistakes
- Filling a lavender (EDTA) tube before the light blue or serum tubes, so additive can carry into later tubes.
- Drawing a plastic clot-activator tube before the light blue tube.
- Under-filling a light blue tube.
- Shaking tubes instead of inverting gently.
Practice this skill
Practise the sequence in the app with critical-step highlighting and a rationale for each step.
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Sources and how we check them: How we verify.