Question 77

Sodium citrate is the appropriate additive for a coagulation specimen.

Sodium citrate is the correct additive for a coagulation specimen as it acts as an anticoagulant, preventing blood from clotting and allowing accurate measurement of coagulation parameters.

A) Lithium heparin

Lithium heparin is not the correct choice for a coagulation specimen. While it does act as an anticoagulant, it is primarily used for tests such as chemistry panels and is not suitable for coagulation studies, as it can interfere with the clotting cascade.

B) Sodium heparin

Sodium heparin is also an anticoagulant; however, it is not the standard choice for coagulation testing. Like lithium heparin, it can affect the results of coagulation tests and is typically used for other laboratory analyses, making it inappropriate for this purpose.

C) EDTA

EDTA is a powerful anticoagulant, but it is primarily used for hematology tests and not for coagulation studies. The presence of EDTA can interfere with coagulation factor activity, leading to inaccurate results in coagulation assays.

D) Sodium citrate

Sodium citrate is the correct additive for coagulation specimens. It effectively chelates calcium in the blood, which is necessary for the coagulation process, thereby allowing for accurate measurement of various coagulation parameters without interference.

Conclusion

Sodium citrate is definitively the right choice for coagulation specimens due to its role in maintaining the integrity of the coagulation process. In contrast, lithium heparin, sodium heparin, and EDTA, while effective anticoagulants, are unsuitable for coagulation testing as they can compromise test accuracy. Thus, sodium citrate is essential for reliable coagulation results.