Understanding the Different Types of Venous Blood Collection Tubes in Phlebotomy

Summary

• Understanding the different types of venous blood collection tubes is essential in phlebotomy.
• Each type of tube is color-coded to denote the additives present, which serve specific purposes in preserving the blood sample.
• Phlebotomists must be familiar with the various tubes to ensure accurate Test Results and proper patient care.

When it comes to phlebotomy, the process of drawing blood for diagnostic purposes, venous blood collection tubes play a crucial role. These tubes are designed to collect and preserve blood samples for laboratory testing. Each tube is color-coded to denote the additives present, which serve specific purposes in preserving the blood sample. In this article, we will explore the different types of venous blood collection tubes commonly used in phlebotomy.

Red-Top Tubes

Red-top tubes, also known as serum tubes, are one of the most common types of venous blood collection tubes used in phlebotomy. These tubes do not contain any additives and are used to collect blood for tests that require serum samples. The red color of the stopper signifies that the tube does not contain any anticoagulants. After the blood is allowed to clot, the tube is centrifuged to separate the serum from the clotted blood cells. Serum can then be used for a wide range of tests, including cholesterol, glucose, and liver function tests.

Lavender-Top Tubes

Lavender-top tubes, also known as EDTA tubes, contain the Anticoagulant ethylenediaminetetraacetic acid (EDTA). The lavender color of the stopper indicates the presence of this additive, which prevents blood clotting by binding calcium ions. These tubes are used for tests that require whole blood samples, such as complete blood counts (CBC) and blood typing. EDTA tubes are also commonly used for molecular Diagnostic Tests, as the Anticoagulant preserves DNA and RNA in the blood sample.

Green-Top Tubes

Green-top tubes, also known as Heparin tubes, contain the Anticoagulant Heparin. The green color of the stopper signifies the presence of Heparin, which inhibits clotting by enhancing the activity of antithrombin, a natural clotting inhibitor in the blood. These tubes are used for tests that require plasma samples, such as coagulation studies and some chemistry tests. Heparin tubes are also used for blood gas analysis, as they do not interfere with the results.

Gray-Top Tubes

Gray-top tubes are used for tests that require glucose measurement. These tubes contain the additive Sodium Fluoride, which inhibits glycolysis, the breakdown of glucose in the blood sample. In addition to Sodium Fluoride, gray-top tubes may also contain Potassium Oxalate, another glycolysis inhibitor. The gray color of the stopper indicates the presence of these additives. Gray-top tubes are commonly used for glucose tolerance tests and to monitor blood sugar levels in diabetic patients.

Blue-Top Tubes

Blue-top tubes, also known as citrate tubes, contain the Anticoagulant Sodium Citrate. The blue color of the stopper signifies the presence of this additive, which binds calcium ions and prevents blood clotting by inhibiting the coagulation cascade. These tubes are primarily used for coagulation studies, such as Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT) tests. Citrate tubes are essential for monitoring patients on Anticoagulant therapy, such as warfarin or Heparin.

Conclusion

Understanding the different types of venous blood collection tubes is essential for phlebotomists to ensure accurate Test Results and proper patient care. Each type of tube is color-coded to denote the additives present, which serve specific purposes in preserving the blood sample. Red-top tubes are used for serum samples, lavender-top tubes for whole blood samples, green-top tubes for plasma samples, gray-top tubes for glucose measurement, and blue-top tubes for coagulation studies. Phlebotomists must be familiar with the various tubes and their uses to effectively collect and preserve blood samples for laboratory testing.

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