Properly collecting blood specimens is a critical skill for phlebotomists and other healthcare workers who perform venipuncture. One key aspect of proper specimen collection is drawing blood tubes in the correct order. Following the proper order of draw helps ensure accurate test results by avoiding cross-contamination between tubes. However, remembering the correct tube order can be challenging given the multiple tube options and additives. This article will provide tips and memory aids to help you reliably recall the proper sequence for drawing common blood collection tubes.
Overview of Blood Collection Tubes
Blood collection tubes contain various additives designed for different types of tests. The main types of tubes are:
| Tube Type | Tube Additive | Tube Color | Common Tests |
|---|---|---|---|
| Blood cultures | No additives | Various colors | Blood cultures |
| Serum separator | Clot activator and gel separator | Gold, red/black | Chemistry, serology |
| Heparin | Liquid heparin | Green | Hematology, chemistry |
| EDTA | EDTA anticoagulant | Lavender | Hematology |
| Citrate | Liquid citrate anticoagulant | Light blue | Coagulation |
| SST | Gel and clot activator | Gold, tiger top | Chemistry, serology |
Understanding the additives in each tube type is key to remembering the proper order of draw.
Order of Draw Rules
The order of draw is the sequence in which blood collection tubes must be filled. The CLSI (Clinical and Laboratory Standards Institute) provides the following guidelines for order of draw:
- Blood cultures and sterile tubes (no additives)
- Sodium citrate tubes (light blue)
- Serum tubes with clot activator (red, gold, and speckled tubes)
- Heparin tubes (green)
- EDTA tubes (lavender)
- Glycolytic inhibitor tubes (gray)
- Any remaining specialty tubes
The key objectives behind these guidelines are:
- Obtain blood cultures first to avoid contamination
- Draw coagulation tubes before other additives affect platelet function
- Separate serum tubes from cells while clotting occurs
- Preserve blood cell morphology with EDTA and heparin
- Avoid cross-contamination between tube additives
There are some exceptions. For example, if only serum (gold SST tube) and EDTA tubes are being collected, the EDTA can be drawn first. Also, for fingersticks, the sterile tube should not be first.
Tips to Remember Tube Order
Memorizing the order of draw is essential for error-free phlebotomy. Here are some tips and tricks:
Use Mnemonics
Mnemonic devices use the first letters of key words to make a memorable phrase. Examples include:
- “Candy Canes Create Cheer” – Cultures, Citrate, Clot, Heparin, EDTA
- “No Tapping, Sterile is First” – Needle, Test Tubes, Sterile
- “Red before blue, green in the middle too” – Red SST, blue citrate, green heparin
Come up with your own mnemonics that connect tube names, colors, or additives. Say them out loud when performing venipuncture.
Visualize Colors in Order
Picture the tube colors in sequence:
Clear or pink (blood cultures) → light blue (citrate) → red and gold (serum) → green (heparin) → lavender (EDTA)
You can also visualize tubes stacked by color.
Focus on Key Pairs
Remembering just a few key pairs can guide overall sequence:
- Cultures first
- Citrate before serum and heparin tubes
- Heparin before EDTA
The pairs relate to cross-contamination concerns.
Follow Your Institution’s Protocol
Most hospitals and labs have a set protocol for order of draw. Stick to the established procedure. It may also be displayed visually in phlebotomy rooms.
Validate with Electronics
Some facilities have phlebotomy devices that prompt for the correct tube order electronically when each tube is filled. Let technology validate your technique.
Quiz Yourself
Regularly review tube order and test yourself. Flash cards are an easy self-testing method.
Conclusion
Order of draw is a detail that is easy to mix up but very important. By learning some memory aids and tricks, phlebotomists can develop confidence in their technique. Mnemonics, visualizing colors, focusing on key pairs, and quizzing oneself are all helpful strategies. Consistently practicing the right order of draw helps avoid errors and ensure accurate test results. Mastering this crucial skill is vital for patient safety and quality phlebotomy care.