Understanding Blood Collection Tube Colors

Guide to Blood Collection Tubes: Tube Color for Each Blood Test
Blood collection is a fundamental process in medical diagnostics, providing crucial information for the diagnosis, treatment, and monitoring of diseases. The use of color-coded blood collection tubes is essential in ensuring the accuracy and reliability of test results. Each tube color corresponds to a specific additive and intended test, which helps prevent contamination and ensures the integrity of the blood sample. This guide will cover the various blood collection tubes, their colors, and the specific tests they are used for, providing a comprehensive reference for doctors and healthcare professionals.

Overview of Blood Collection Tubes
Blood collection tubes are designed with specific additives to preserve the sample and facilitate particular types of tests. These additives may include anticoagulants, clot activators, or preservatives, and the tube color typically indicates the type of additive present. Proper identification and use of these tubes are critical for accurate laboratory results.

Common Blood Collection Tube Colors and Their Uses

1. Red Top Tubes (No Additive/Clot Activator)
2. Gold or Yellow Top Tubes (Serum Separator Tube - SST)
3. Light Blue Top Tubes (Sodium Citrate)
4. Green Top Tubes (Heparin)
5. Lavender or Purple Top Tubes (EDTA)
6. Gray Top Tubes (Potassium Oxalate/Sodium Fluoride)
7. Pink Top Tubes (EDTA)
8. Light Green or Green-Gray Top Tubes (Plasma Separator Tube - PST)
9. Royal Blue Top Tubes (Trace Element-Free)
10. Tan Top Tubes (Lead-Free)
11. Yellow Top Tubes (ACD Solution A or B)
12. Black Top Tubes (Sodium Citrate for ESR)

Detailed Description of Each Tube and Its Uses

1. Red Top Tubes (No Additive/Clot Activator)
Description:

• Red top tubes do not contain any anticoagulants or preservatives. They may have a clot activator to expedite the clotting process.

Common Tests:

• Serum chemistry tests
• Blood bank testing
• Drug levels

Usage:

• After collection, the blood is allowed to clot by standing upright at room temperature, then centrifuged to separate the serum.

2. Gold or Yellow Top Tubes (Serum Separator Tube - SST)
Description:

• These tubes contain a gel that separates the serum from the blood cells upon centrifugation.

Common Tests:

• Routine chemistry panels
• Hormone levels
• Serology

Usage:

• Blood is allowed to clot before centrifugation to obtain serum.

3. Light Blue Top Tubes (Sodium Citrate)
Description:

• Light blue tubes contain sodium citrate, an anticoagulant that binds calcium in the blood.

Common Tests:

• Coagulation studies (e.g., PT, aPTT)
• D-dimer

Usage:

• It is crucial to fill these tubes to the correct volume to ensure accurate test results.

4. Green Top Tubes (Heparin)
Description:

• Green tubes contain heparin, which prevents blood from clotting by inhibiting thrombin and thromboplastin.

Common Tests:

• Plasma chemistry tests
• Ammonia levels
• Electrolytes

Usage:

• These tubes are often used when immediate plasma analysis is required.

5. Lavender or Purple Top Tubes (EDTA)
Description:

• These tubes contain EDTA (ethylenediaminetetraacetic acid), an anticoagulant that binds calcium ions.

Common Tests:

• Complete Blood Count (CBC)
• Hemoglobin A1c
• Blood smears

Usage:

• EDTA is preferred for hematological studies due to its ability to preserve cell morphology.

6. Gray Top Tubes (Potassium Oxalate/Sodium Fluoride)
Description:

• Gray top tubes contain potassium oxalate as an anticoagulant and sodium fluoride as a preservative.

Common Tests:

• Glucose tolerance test
• Blood alcohol levels
• Lactate

Usage:

• Sodium fluoride inhibits glycolysis, making these tubes ideal for glucose measurements.

7. Pink Top Tubes (EDTA)
Description:

• Pink tubes also contain EDTA but are specifically designed for blood bank procedures.

Common Tests:

• Blood typing
• Crossmatching
• Antibody screening

Usage:

• The tube’s special labeling ensures traceability in blood bank environments.

8. Light Green or Green-Gray Top Tubes (Plasma Separator Tube - PST)
Description:

• These tubes contain lithium heparin and a gel for plasma separation.

Common Tests:

• STAT chemistry tests
• Electrolytes

Usage:

• They provide quick plasma separation, which is essential for urgent testing.

9. Royal Blue Top Tubes (Trace Element-Free)
Description:

• Royal blue tubes are designed to be free of trace elements and may contain either no additive or EDTA.

Common Tests:

• Trace metal analysis (e.g., lead, mercury)
• Toxicology studies

Usage:

• These tubes prevent contamination of the sample by trace elements.

10. Tan Top Tubes (Lead-Free)
Description:

• Tan tubes are similar to royal blue but are specifically certified as lead-free.

Common Tests:

• Lead levels

Usage:

• Ensuring no lead contamination is critical for accurate assessment.

11. Yellow Top Tubes (ACD Solution A or B)
Description:

• Yellow tubes contain Acid Citrate Dextrose (ACD) solution, either A or B, which acts as an anticoagulant and preservative.

Common Tests:

• HLA phenotyping
• DNA testing
• Paternity testing

Usage:

• The ACD solution maintains red blood cell viability for these specific tests.

12. Black Top Tubes (Sodium Citrate for ESR)
Description:

• Black tubes contain sodium citrate and are used for erythrocyte sedimentation rate (ESR) testing.

Common Tests:

• ESR

Usage:

• Accurate volume filling is crucial to maintain the correct blood-to-anticoagulant ratio.

Best Practices for Blood Collection
1. Proper Identification and Labeling:

• Ensure patient information is correctly labeled on each tube to prevent sample mix-ups.

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2. Correct Order of Draw:

• Follow the recommended order of draw to avoid cross-contamination of additives between tubes.

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3. Adequate Mixing:

• Gently invert tubes several times immediately after collection to mix blood with additives. Do not shake vigorously.

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4. Proper Storage and Transport:

• Store and transport tubes according to specific test requirements to maintain sample integrity.

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Importance of Understanding Blood Collection Tubes
Understanding the appropriate use of blood collection tubes is vital for healthcare professionals to ensure accurate and reliable test results. Misuse of these tubes can lead to erroneous results, affecting patient diagnosis and treatment. Staying informed about the latest guidelines and best practices in blood collection can enhance the quality of care provided to patients.

References

1. LabCorp. Clinical Biochemistry. Available at: https://www.labcorp.com/tests/clinical-laboratory-tests/clinical-biochemistry
2. Quest Diagnostics. Testing Services. Available at: https://www.questdiagnostics.com/home/physicians/testing-services
3. Mayo Clinic Laboratories. Test Catalog. Available at: https://www.mayocliniclabs.com/test-catalog/overview/CLL