Common Order of Draw Mistakes
Getting the order of draw wrong doesn't just risk a written-exam question — in practice it can carry additive between tubes and silently invalidate real lab results, which is why instructors treat it as a hard-stop error, not a minor one.
How this procedure is evaluated
Your training program instructor or clinical preceptor observes your technique and decides whether a draw or procedure counts toward your required documentation (at least 30 venipunctures and 10 capillary punctures for NHA CPT eligibility). A technique error doesn't just risk the sample — it can mean the attempt doesn't count toward your total.
The 5 Most Common Mistakes
Drawing the red/SST tube before the light blue citrate tube, which can carry clot activator into the coagulation tube and invalidate PT/PTT results.
Shaking tubes instead of gently inverting them, which can cause hemolysis.
Forgetting that blood cultures always come first, even before coagulation tubes, to protect sterility.
Under- or over-inverting a tube relative to its required count.
Confusing lavender/pink (EDTA, for CBC) with light blue (citrate, for coagulation) under time pressure.
Exactly What Your Instructor Is Checking
These are the specific checkpoints your instructor or preceptor documents for this procedure.
- ✓
States the six-tube sequence from memory without hesitation: blood culture → light blue → red/gold/SST → green → lavender/pink → gray.
- ✓
Correctly explains why the sequence exists (preventing additive carryover between tubes).
- ✓
Inverts each tube the correct number of times immediately after filling.
- ✓
Adjusts the sequence correctly when a blood culture is not ordered (starts with light blue).
- ✓
Never shakes a tube — uses gentle end-over-end inversion only.
How to Avoid These Mistakes
These tips come from the most common mistake patterns in Order of Draw.
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Use a mnemonic you've practiced out loud, not just read silently — verbal recall under pressure is different from recognition.
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If a requisition only orders one or two tests, you only need to draw the tubes those tests require, still in correct relative order.
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This is the fact most likely to appear on the written exam in a "which tube is drawn first/last" format — know it cold, not just generally.
Practice checklist →
Printable step-by-step checklist
What to say →
Exact verbal cues for patient interaction
Practice the written exam too
500 free NHA CPT practice questions with instant explanations.
Take the Practice Test →