The Importance of Following the Correct Order of Draw in Blood Collection

Summary

• The order of draw is a critical process in blood collection to prevent contamination and ensure accurate Test Results.
• The order of draw is established based on the principles of additive carryover and Anticoagulant interference.
• Following the correct order of draw can help healthcare professionals avoid issues such as sample hemolysis and inaccurate Test Results.

When it comes to drawing blood for Diagnostic Tests, the order in which blood samples are collected is crucial to ensure accurate results. The order of draw refers to the sequence in which different blood tubes are filled during the blood collection process. Establishing a standardized order of draw helps to prevent Cross-Contamination between samples and minimize the risk of erroneous Test Results due to factors such as additive carryover and Anticoagulant interference.

Why is the order of draw important?

The order of draw is important for several reasons, including:

Preventing contamination

When multiple blood samples are collected in the same phlebotomy session, there is a risk of Cross-Contamination between tubes if the order of draw is not followed. For example, if a tube containing an Anticoagulant is drawn after a tube without an anticoagulant, the Anticoagulant from the previous tube may contaminate the subsequent sample, leading to inaccurate Test Results. Following the correct order of draw helps to minimize this risk and ensure the integrity of the samples.

Avoiding additive carryover

Some blood collection tubes contain additives such as clot activators, anticoagulants, or preservatives to help preserve the integrity of the sample or facilitate specific tests. However, if these additives are not properly mixed with the blood sample or if there is carryover from a previous tube, it can affect the accuracy of the Test Results. By following the established order of draw, healthcare professionals can minimize the risk of additive carryover and ensure reliable Test Results.

Preventing Anticoagulant interference

Anticoagulants are commonly used in blood collection tubes to prevent blood clotting and preserve the integrity of the sample for testing. However, some anticoagulants, such as EDTA, can interfere with certain tests if they are not properly mixed with the blood sample or if there is contamination from a previous tube. By following the correct order of draw, healthcare professionals can minimize the risk of Anticoagulant interference and ensure accurate Test Results.

How is the order of draw established?

The order of draw is typically established based on the principles of additive carryover and Anticoagulant interference. Healthcare organizations and professional societies such as the Clinical and Laboratory Standards Institute (CLSI) provide guidelines and recommendations for the proper order of draw to ensure the accuracy and reliability of Test Results.

While the specific order of draw may vary depending on the organization or laboratory, the general principles remain the same. The order of draw is typically organized based on the type of additive in the blood collection tubes, with tubes containing anticoagulants drawn before tubes without additives to minimize the risk of contamination and interference.

Common order of draw

Although there may be variations in the order of draw depending on the specific protocols followed by a healthcare facility or laboratory, the following is a common order of draw that is widely accepted:

1. Yellow (SPS) or sterile (red) Blood Culture tubes
2. Citrate tubes (Light Blue Top)
3. Serum tubes with or without Clot Activator (red or gold/ tiger top)
4. Heparin tubes (green top)
5. EDTA tubes (Lavender Top)
6. Glycolytic inhibitor tubes (gray top)

By following this standard order of draw, healthcare professionals can minimize the risk of contamination and interference between samples, thereby ensuring the accuracy and reliability of Test Results.

Conclusion

The order of draw is a critical process in blood collection that helps to ensure the accuracy and reliability of diagnostic Test Results. By following the established order of draw based on principles of additive carryover and Anticoagulant interference, healthcare professionals can minimize the risk of contamination and ensure the integrity of blood samples. Adhering to the correct order of draw is essential for providing quality patient care and delivering accurate Test Results that can guide appropriate medical treatment decisions.

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