Health Education

Blood Collection Tube Colors and Tests: A Comprehensive Guide

Blood collection tubes play an important role in medical diagnostics. Healthcare professionals can gather valuable insights into a patient’s health. The color-coded system of these tubes is to facilitate the identification of additives and their functions. It ensures accurate and reliable test results. We will delve into the significance of blood collection tube colors and tests by providing a detailed understanding for both healthcare professionals and those with limited medical backgrounds.

Overview of Blood Collection Tubes

Blood collection tubes are specially designed vessels. They are used to collect blood samples for various diagnostic purposes. The tubes contain additives that either promote or inhibit blood clotting. It further depends on the requirements of specific laboratory tests. 

The most commonly used laboratory tube colors for blood tests are: 

  • light blue, 
  • red, 
  • green, 
  • lavender, 
  • gray, 
  • yellow, 
  • tan, 
  • pink, 
  • royal blue, 
  • pearl, and 
  • gold. 

Each of them serves a distinct purpose in the realm of medical testing.

Guide to Phlebotomy Tubes and Tests: Color-Coded Tubes and Their Uses

Let’s dive into the phlebotomy tube color guide. Decode the meaning and uses of different color-coded tubes:

1. Gray Top:

The gray stopper indicates that a tube is designed for glycolic inhibition, and contains potassium oxalate, sodium fluoride, or Na2 EDTA. 

Gray tubes are commonly used to test results when a delay in glucose level is expected. Tests conducted with gray tubes encompass: 

  • blood alcohol levels, 
  • glucose levels, 
  • bicarbonate levels, 
  • lactate levels, 
  • lipid panels, 
  • liver function tests, 
  • electrolyte analysis, and 
  • therapeutic drug monitoring.

2. Lavender/Purple Top:

Lavender/purple-topped tubes contain ethylenediaminetetraacetic acid (EDTA) and are chosen for draws requiring stable blood constituents without coagulation for up to 24 hours. 

These tubes are selected for various tests such as 

  • white blood cell count, 
  • red blood cell count, 
  • platelet count, 
  • eosinophil count, 
  • erythrocyte sedimentation rate, 
  • tests for sickle cells, and 
  • hemoglobin levels.

3. Green Top:

The tubes with the Green-top contain ammonium heparin, lithium heparin, or sodium heparin coatings, and serve in STAT and routine chemistry. 

They are unsuitable for blood banking procedures and have specific restrictions based on the type of heparin present.

4. Red Top:

Red-topped tubes denote draws for serology and immunohematology and have clot activators on their interior surfaces.

Serology applications include strep testing, cold agglutinins, haptoglobin, C-reactive protein, and rubella titer.

5. Light Blue Top:

Tubes with a Light blue top contain 3.2% sodium citrate. They are potent anticoagulants. 

They are used for tests such as:

  • fibrinogen, 
  • fibrin degradation products, 
  • thrombin time, 
  • prothrombin time, and 
  • D-dimer.

6. Yellow Top:

Yellow-topped tubes contain a combination of citric acid, dextrose, and trisodium citrate.

They are used for DNA studies and HIV cultures.

7. Tan, Pink, Royal Blue, Pearl, and Gold Top

Tan-colored tubes are used for lead-level tests.

Pink-colored tubes for HIV viral load tests, compatibility studies, and blood type screening.

Royal blue-capped tubes are ideal for drug levels, toxicology, and trace element concentration tests.

Pearl tubes are used for HHV-6, adenovirus, and toxoplasma PCRs.

Gold-topped tubes, containing a serum separator gel, are versatile and used for various tests, including hepatitis, HIV, serology, and endocrinology testing.

The Significance of Tube Colors in Phlebotomy

In phlebotomy using different tube colors is not arbitrary.  It is a meticulously designed system to ensure the integrity of blood samples and the accuracy of test results. Understanding the significance of tube colors is paramount for healthcare professionals. It helps them to perform their duties effectively.

Handling and Precautions

The proper handling and precautions are important because:

  • Proper handling of blood collection tubes is the key to maintaining the integrity of the samples. 
  • It also ensures accurate test results. 
  • Blood tube color coding for healthcare professionals is the key to ensuring accuracy. 
  • They should follow the established protocols for specimen collection, transportation, and storage. 
  • Additionally, certain precautions must be followed strictly, such as avoiding contamination and ensuring that the tubes are properly labeled.

Technology and Innovations in Blood Collection

Technology and Innovations in Blood Collection

Advancements in technology have contributed alot in improvements in blood collection and testing methodologies. The use of automated systems and innovative materials for tube construction has enhanced the accuracy. It has also enhanced the efficiency of diagnostic processes. Keep informed about the latest developments in blood collection technology. It will help to ensure optimal patient care.


Understanding the blood test tube colors is important for both healthcare professionals and individuals seeking insights into their health. This guide aims to provide a comprehensive overview of the various tube colors and their corresponding tests. It emphasizes the significance of this color-coded system in the field of phlebotomy. By adhering to proper handling procedures and staying informed about technological advancements, healthcare providers ensure the reliability of diagnostic results, ultimately contributing to improved patient outcomes. 

Medical Disclaimer: We only provide information for educational purposes. Do not consider it a medical advice for you. In case of need, consult the healthcare professional for proper diagnosis and treatment.

Kelly Han

Dr. Kelly Han is a seasoned medical professional with a passion for holistic wellness and integrative health. Based in San Francisco, her expertise spans across various domains of health, from fitness and skincare to oral health and weight management. Understanding the intricate connections between different aspects of health, Dr. Han believes in a comprehensive approach. Whether it's the latest skincare regimen, effective weight loss strategies, or understanding hormonal imbalances, she's dedicated to providing readers with evidence-based advice and actionable insights on a wide array of health topics. Through her articles, Dr. Han aims to empower individuals to take charge of their well-being, offering them the knowledge and tools they need to lead healthier, more vibrant lives. Join her in exploring the multifaceted world of health, beauty, and wellness.

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