Which color top is used for EDTA toxicology testing?

• A. Red
• B. Lavender
• C. Gray
• D. Royal Blue

Answer: (D)

In EDTA toxicology testing, you use a tube that is specifically designated for toxicology analyses and contains EDTA as the preservative. The color that signals this purpose is Royal Blue. Royal blue tubes are produced for trace-element and toxicology work and are chosen to prevent clotting without introducing other additives that could interfere with toxicology results. Lavender tops also contain EDTA, but they’re used for hematology tests like CBCs, not for toxicology workflows. Red tops have no additive, and gray tops use fluoride/oxalate for glucose testing, which aren’t appropriate for EDTA-based toxicology. So, the correct color for EDTA toxicology testing is Royal Blue.