Lecture Notes: Proper Order of Blood Draw

Introduction

• Presenter: Eddie Watson
• Platform: ICU Advantage
• Topic: Importance of the order of draw in blood sampling/phlebotomy
• Objective: Understand the correct order of draw to prevent cross-contamination and ensure accurate lab results.

Importance of Proper Order of Draw

• Impact on Patients: Proper order is crucial to avoid cross-contamination and inaccurate results which could lead to misdiagnosis and improper treatment.
• Additives: Incorrect order may cause transfer of additives between tubes, affecting test results.

Types of Blood Sampling Tubes

1. Blood Cultures

• Types: Aerobic and anaerobic
• Importance: Draw first to avoid contamination.
• Contents: Nutrient broth, anticoagulant, and chemicals to prevent bacterial killing by blood.
  • Order: Aerobic first to avoid issues with air in the syringe.

2. Light Blue Tube

• Purpose: Coagulation tests (PT, INR, PTT, etc.)
• Additive: Sodium citrate, requires precise blood-to-additive ratio.

3. Red Top Tube

• Usage: Chemistry panels requiring serum, less common.
• Additive: May contain silica clot activator.

4. Gold/SST (Serum Separator Tube)

• Usage: Chemistry tests, typically send-out tests.
• Additive: Gel to separate serum from cells, may include clot activator.

5. Green Top Tube

• Usage: Standard chemistry tests, cardiac markers (e.g., troponin).
• Special Handling: Some tests (e.g., ammonia, ionized calcium) require the tube to be on ice.
• Additives: Plasma separating gel, heparin.

6. Purple Top Tube

• Purpose: Hematology (CBC, ESR, A1C)
• Additive: EDTA, preserves cell morphology and prevents clotting.

7. Pink Top Tube

• Usage: Blood type tests
• Similar to: Purple top but specifically for blood banking.

8. Gray Top Tube

• Tests: Lactate, ethanol, fasting glucose
• Additives: Sodium fluoride (stops glycolysis), potassium oxalate (prevents clotting).

Proper Order of Draw

1. Blood Cultures: Prevents contamination.
2. Light Blue: Ensures precise anticoagulant ratio.
3. Red: Less commonly used for general chemistry.
4. Gold/SST: Send-out chemistry tests.
5. Green: Common chemistry tests within hospitals.
6. Purple: Hematology tests.
7. Pink: Blood type tests.
8. Gray: Lactate, fasting glucose, and ethanol tests.

Mnemonic for Order of Draw

• Mnemonic: Stoplight Red Stay Green Power Light Go
  • S: Sterile (Blood Cultures)
  • L: Light Blue
  • R: Red
  • S: SST (Gold)
  • G: Green
  • P: Purple
  • L: Light (Pink)
  • G: Gray

Conclusion

• Reiteration of Importance: Correct draw order is vital for accurate lab results and patient care.

• Learning Tips: Understanding the purpose of each tube can help memorize the order and prevent errors in practice.

• Engagement: Reflect on initial guess of order and share thoughts in comments.

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