Order of Draw Importance in Phlebotomy: Prevent Contamination and Ensure Reliable Test Results
Summary
- Proper order of draw is crucial for collecting accurate blood samples.
- Different colored tubes are used for different types of tests in phlebotomy.
- Following the correct order of draw can prevent sample contamination and ensure reliable Test Results.
Introduction
Phlebotomy is the process of drawing blood from a patient for clinical or medical testing, transfusions, donations, or research purposes. The proper order of draw is essential to ensure accurate blood samples are collected and reliable Test Results are obtained. In this blog post, we will discuss the importance of the correct order of draw and explore the different colored tubes used in phlebotomy for collecting blood samples in home healthcare, clinical labs, and hospitals in the United States.
The Importance of Order of Draw
The order of draw refers to the sequence in which blood samples are collected into different colored tubes during a phlebotomy procedure. Following the proper order of draw is crucial for several reasons:
- Preventing Cross-Contamination: Collecting blood samples in the wrong order can lead to contamination of samples with additives from other tubes, affecting Test Results.
- Ensuring accurate Test Results: Different colored tubes contain specific additives that interact with blood components, and drawing blood in the correct order helps to maintain the integrity of the sample for precise test outcomes.
- Complying with industry standards: Following the established order of draw guidelines ensures consistency in phlebotomy practices and aligns with regulatory requirements for sample collection.
Commonly Used Tube Colors in Phlebotomy
Phlebotomy tubes come in a variety of colors, each denoting specific additives or purposes for different types of tests. Understanding the significance of various tube colors is essential for phlebotomists to correctly collect and handle blood samples. Here are some commonly used tube colors in phlebotomy and their corresponding additives:
1. Red or Tiger Top Tube (SST - Serum Separator Tube)
The red or tiger top tube contains a gel separator that separates serum from the clot after the blood is centrifuged. This tube is commonly used for chemistry and serology tests, as well as for hormone and drug level measurements.
2. Lavender or Purple Top Tube (EDTA - Ethylenediaminetetraacetic Acid)
The lavender or purple top tube contains EDTA, an Anticoagulant that prevents blood clotting by binding to calcium. This tube is used for hematology testing, such as complete blood count (CBC) and blood cell morphology examination.
3. Light Blue Top Tube (Sodium Citrate)
The Light Blue Top tube contains Sodium Citrate, an Anticoagulant that binds calcium to prevent blood clotting. This tube is commonly used for coagulation tests, such as Prothrombin Time (PT) and Activated Partial Thromboplastin Time (aPTT).
4. Green Top Tube (Heparin)
The green top tube contains Heparin, an Anticoagulant that inhibits thrombin formation. This tube is used for chemistry and electrolyte tests, as well as for blood gas analysis.
5. Gray Top Tube (Sodium Fluoride/Potassium Oxalate)
The gray top tube contains Sodium Fluoride and Potassium Oxalate, which preserve glucose levels by inhibiting glycolysis. This tube is primarily used for glucose testing, such as Fasting blood sugar or glucose tolerance tests.
The Correct Order of Draw
Based on the different colored tubes and their respective additives, the proper order of draw for collecting blood samples in phlebotomy is as follows:
- Yellow or Light Blue (Blood Culture Tubes)
- Light Blue (Coagulation Tests)
- Red or Tiger Top (Serum Separator Tubes)
- Green (Heparin Tubes)
- Lavender (EDTA Tubes)
- Gray (Sodium Fluoride/Potassium Oxalate Tubes)
Following this sequential order ensures that blood samples are collected accurately, without the risk of contamination or interference between additives in different tubes. It is essential for phlebotomists to adhere to the proper order of draw guidelines to maintain the integrity of blood samples and obtain reliable Test Results.
Conclusion
Understanding the proper order of draw for collecting blood samples in phlebotomy is essential for ensuring the accuracy and reliability of clinical Test Results. Different colored tubes with specific additives play a crucial role in preserving the integrity of blood samples and facilitating accurate testing processes. By following the correct order of draw guidelines and handling blood samples appropriately, healthcare professionals in home healthcare, clinical labs, and hospitals can maintain high standards of phlebotomy practice and deliver quality patient care.
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