what color tube for vanco trough

2 min read 04-02-2025

Choosing the right blood collection tube for drawing a vancomycin trough level is crucial for accurate results. The wrong tube can compromise the test, leading to inaccurate readings and potentially impacting patient care. This article clarifies which tube to use and why.

The Importance of Accurate Vancomycin Trough Levels

Vancomycin is a powerful antibiotic frequently used to treat serious bacterial infections. Monitoring vancomycin levels is essential to ensure the drug is effective while minimizing the risk of side effects like nephrotoxicity (kidney damage) and ototoxicity (hearing loss). A trough level—the lowest concentration of the drug in the blood—is measured just before the next dose is administered. This helps healthcare providers adjust the dosage for optimal therapeutic effect.

The Correct Tube: Red Top (No Additive)

For accurate vancomycin trough level testing, a red top tube (with no additives) is the standard choice. This is because additives in other tubes can interfere with the drug's concentration, leading to inaccurate results.

Why Other Tubes Are Inappropriate:

Lavender Top (EDTA): EDTA is an anticoagulant that chelates (binds to) certain metals. This can affect the vancomycin assay, leading to inaccurate readings. Avoid lavender tops for trough levels.
Light Blue Top (Sodium Citrate): Used for coagulation studies, these tubes contain sodium citrate, an anticoagulant that would also interfere with the vancomycin assay.
Green Top (Heparin): Heparin, another anticoagulant, can also cause interference with the vancomycin test.

Why a Red Top Tube is Essential

The red top tube contains no additives, ensuring that the vancomycin concentration remains unaltered. This provides a pure sample for accurate laboratory analysis. The lack of interference allows for the most reliable measurement of the trough level, enabling healthcare providers to make informed decisions about medication adjustments.

Proper Procedure for Collection

Beyond the tube selection, proper collection technique is equally vital for accurate results. Ensure proper patient identification, and follow established phlebotomy procedures. The blood sample should be collected immediately before the next scheduled dose of vancomycin. Remember to clearly label the tube with the patient's information and the time of collection.

Conclusion: Red Top for Reliability

In summary, when drawing a vancomycin trough level, always use a red top (plain) vacuum tube. This is the only tube type that guarantees accurate and reliable results. Using any other type of tube risks inaccurate measurements, potentially compromising patient care. Always consult your institution's guidelines and procedures for the most up-to-date recommendations. If there are any uncertainties, consulting with a clinical laboratory professional is always the best practice.