Which tube is used for ETOH, glucose testing (if used alone), and lactic acid on ice, with no tourniquet?

Which tube is used for ETOH, glucose testing (if used alone), and lactic acid on ice, with no tourniquet?

• A. Canary Yellow Tube — SPS
• B. Red Tube — No additive
• C. Gray Tube — Na Fluoride/K Oxalate
• D. Lt Blue Tube — Na Citrate

Answer: (C)

A gray-top tube with sodium fluoride and potassium oxalate is the best choice because it combines an antiglycolytic agent with an anticoagulant, which is essential for preserving glucose and stabilizing lactate after collection. Sodium fluoride inhibits glycolysis, helping keep glucose levels accurate if tested alone and slowing the metabolic production of lactate ex vivo. This same tube is commonly used for lactic acid testing when samples are placed on ice, since lactic acid is highly susceptible to changes from cellular metabolism once drawn. Avoiding a tourniquet minimizes tissue hypoxia and venous stasis that could falsely elevate lactate and other analytes. Ethanol testing can be performed in this tube as well, making it suitable for all three tests in combination. The other tubes lack the antiglycolytic additive or are designed for different purposes, so they wouldn’t reliably preserve glucose or lactate (and wouldn’t be appropriate for the ethanol test).

A gray-top tube with sodium fluoride and potassium oxalate is the best choice because it combines an antiglycolytic agent with an anticoagulant, which is essential for preserving glucose and stabilizing lactate after collection. Sodium fluoride inhibits glycolysis, helping keep glucose levels accurate if tested alone and slowing the metabolic production of lactate ex vivo. This same tube is commonly used for lactic acid testing when samples are placed on ice, since lactic acid is highly susceptible to changes from cellular metabolism once drawn. Avoiding a tourniquet minimizes tissue hypoxia and venous stasis that could falsely elevate lactate and other analytes. Ethanol testing can be performed in this tube as well, making it suitable for all three tests in combination. The other tubes lack the antiglycolytic additive or are designed for different purposes, so they wouldn’t reliably preserve glucose or lactate (and wouldn’t be appropriate for the ethanol test).