Main Additives in Venous Blood Collection Tubes: Functions and Importance

Summary

• Anticoagulants are additives used in venous blood collection tubes to prevent blood from clotting.
• Serum separators are additives that help separate the blood cells from the serum after centrifugation.
• Polymer gel barriers are used in some tubes to create a physical barrier between the serum and the blood cells.

Introduction

When you go in for a blood test at an urgent care clinic, you may wonder about the different colored tubes used to collect your blood. These tubes contain various additives that serve different purposes in the blood collection process. In this article, we will explore the main additives used in venous blood collection tubes and their functions.

Anticoagulants

Anticoagulants are additives that prevent blood from clotting by inhibiting the clotting factors in the blood. They are essential for collecting whole blood or plasma samples for various laboratory tests. Some common anticoagulants used in venous blood collection tubes include:

1. EDTA (Ethylenediaminetetraacetic Acid)

EDTA is a chelating agent that binds to calcium ions in the blood, which are necessary for the blood to clot. EDTA tubes are typically used for hematology tests, such as complete blood counts (CBC), as they preserve the blood cells and prevent clotting.

2. Sodium Citrate

Sodium Citrate is another common Anticoagulant used in venous blood collection tubes. It works by binding to calcium ions and is often used for coagulation tests, such as Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT).

3. Heparin

Heparin is a natural Anticoagulant produced by the liver that inhibits the clotting factors thrombin and factor Xa. Heparin tubes are commonly used for chemistry tests that require plasma samples, such as lipid panels and glucose tests.

Serum Separators

Serum separators are additives in blood collection tubes that aid in the separation of serum from the blood cells after centrifugation. These additives create a barrier that prevents the blood clot from mixing with the serum, allowing for a clean separation. Common serum separators include:

1. Silica Particles

Silica particles are often used as serum separators in blood collection tubes. These particles enhance the clotting process and help facilitate the separation of serum from the blood cells during centrifugation.

2. Thixotropic Gel

Thixotropic gel is a substance that transitions from a solid to a liquid state under pressure. This property allows the gel to move and create a barrier between the serum and the blood cells during centrifugation, aiding in the separation process.

Polymer Gel Barriers

Some venous blood collection tubes contain polymer gel barriers that create a physical barrier between the serum and the blood cells. These barriers are used in tubes that require a high degree of serum separation and stability. Common polymer gel barriers include:

1. Polyester Gel

Polyester gel barriers are often used in blood collection tubes to prevent the serum from contaminating the blood cells after centrifugation. These barriers help maintain the integrity of the serum sample for accurate laboratory testing.

2. Silicone Gel

Silicone gel barriers are another type of polymer gel used in venous blood collection tubes. These barriers create a physical separation between the serum and the blood cells, ensuring that the two components remain distinct during the testing process.

Conclusion

Understanding the main additives used in venous blood collection tubes is essential for Healthcare Providers and patients alike. Anticoagulants, serum separators, and polymer gel barriers play crucial roles in ensuring the accuracy and reliability of laboratory Test Results. The next time you go in for a blood test at an urgent care clinic, you can have confidence knowing that the additives in the blood collection tubes are working to provide accurate and reliable Test Results.

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