Phlebotomy Tubes Tests & Additives Quiz

Yellow top tubes are designed for blood culture testing to detect microorganisms such as bacteria or fungi in the bloodstream. They contain additives that prevent clotting while preserving microbial viability. This makes them unsuitable for routine chemistry or glucose testing but essential for diagnosing bloodstream infections accurately.

Light blue tubes are used for coagulation studies because they contain sodium citrate, which binds calcium and prevents clotting. Accurate blood-to-additive ratios are critical for reliable clotting results, making this tube essential for tests such as PT and PTT.

Green top tubes contain heparin, an anticoagulant that allows plasma separation. This makes them ideal for plasma-based chemistry tests such as electrolytes and ammonia levels, rather than hematology or blood typing.

Gray top tubes are primarily used for chemistry testing, especially glucose analysis. Their additives prevent glycolysis, ensuring accurate measurement of blood sugar levels over time.

Sodium fluoride in gray top tubes inhibits glycolysis by blocking enzymes involved in glucose metabolism. This preserves glucose concentration in the sample, which is essential for accurate diagnostic testing.

Lavender top tubes contain EDTA, an anticoagulant that preserves cellular components of blood. This makes them ideal for hematology tests such as complete blood counts by preventing clotting without altering cell morphology.

Red and gold tiger top tubes contain clot activators and a gel separator. These additives allow blood to clot and separate serum from cells, making them ideal for serum chemistry and immunology testing.

Yellow top tubes often contain sodium polyanethole sulfonate, an anticoagulant that preserves microorganisms for culture. This additive prevents clotting while maintaining microbial integrity.

Sodium citrate is the additive in light blue tubes. It works by binding calcium, which is required for clot formation. This reversible process allows precise coagulation testing when calcium is reintroduced during analysis.

Gray top tubes are best for glucose testing because their additives prevent cellular metabolism of glucose. This ensures stable glucose levels and accurate laboratory results, especially when sample processing is delayed.