Blood gas analysis preanalytical requirements include being on ice, no clots, and no air bubbles. Which option best reflects these requirements?

• A. On ice, thin fibrin strands only, no air bubbles
• B. On ice, no clots, fewer than 4 air bubbles
• C. On ice, no clots, no air bubbles
• D. Room temp, no clots, no air bubbles

Answer: (C)

Blood gas testing is highly sensitive to how the sample is handled before analysis. Keeping the specimen on ice slows cellular metabolism, which helps preserve the true pO2, pCO2, and pH by limiting gas changes that would occur after collection. It must be free of clots so the gas in the sample truly reflects the blood and can diffuse properly to the analyzer; clots disrupt uniformity and can skew readings. Air bubbles must be avoided because any trapped air exchanges gases with the environment, altering pO2 and pCO2 and giving inaccurate results. Because this combination—on ice, no clots, no air bubbles—best maintains the sample’s original gas content and pH, it is the correct reflection of preanalytical requirements. The other options fail because they permit partial air exposure, room-temperature storage, or clot presence, each of which can bias results.