21/09/2025
Getting the Order of Draw Right: Are You Confident? 🤔
In diagnostics, accuracy begins with the very first step—sample collection. The Order of Draw isn’t just a guideline; it’s a vital procedure that prevents additive carryover between tubes, protecting the accuracy and reliability of patient results.
A single misstep in sequence can dramatically affect test outcomes.
Here’s a concise breakdown of the standard order:
✨ The Correct Order & Tube Purposes at a Glance
1️⃣ Blood Cultures (Aerobic & Anaerobic): Always drawn first to maintain sterility and avoid contamination.
2️⃣ Sodium Citrate (Blue Top): Essential for coagulation studies (e.g., PT, INR).
🔑 Tip: Invert gently 6–8 times.
3️⃣ ACD (Yellow Top): For specialized tests like HLA typing and flow cytometry.
4️⃣ Serum Tubes – Red & Gold Tops: Used in biochemistry, serology, and immunology.
🔑 Tip: Invert gently 6–8 times.
5️⃣ Lithium Heparin (Green Top): Common for plasma chemistry, including organochlorine and cholinesterase tests.
6️⃣ EDTA Tubes (Pink, Purple, Dark Blue):
Pink: Blood bank (Group & Hold, Cross Match)
Purple: Haematology (FBC, HbA1c, Blood Film)
Dark Blue: Trace metals (Zinc, Lead, Copper)
🔑 Tip: Invert gently 6–8 times.
7️⃣ Fluoride Oxalate (Grey Top): For glucose and lactate testing—fluoride prevents glycolysis.
8️⃣ ESR (Black Top): Specifically for Erythrocyte Sedimentation Rate.
✅ Key Takeaway: Respecting the order of draw is non-negotiable. It preserves sample integrity from vein to lab and safeguards patient care
