Which of the following is the anticoagulant of choice for blood gas studies?

For blood gas studies, lithium heparin is the anticoagulant of choice because it does not interfere with the pH and pCO2 measurements essential for these analyses. Blood gas measurements require accurate representation of the patient’s respiratory and metabolic status, and lithium heparin preserves the integrity of the blood sample better than other anticoagulants.

Sodium citrate is commonly used for coagulation studies, as it effectively binds calcium, but its presence can affect the pH and partial pressure measurements when analyzing blood gases. Ammonium oxalate is used primarily for glucose determinations and can lead to hemolysis, which would compromise the analysis of gases. EDTA, while a strong anticoagulant useful in hematology, can also interfere with electrolyte and blood gas measurements due to its ability to chelate metals and its impact on pH. Therefore, lithium heparin stands out as the most suitable anticoagulant for accurate and reliable blood gas measurement.