American Medical Technologist (AMT) Practice Exam

Sodium citrate is the anticoagulant commonly used for coagulation tests due to its ability to effectively bind calcium ions in the blood. Calcium is a crucial factor in the coagulation cascade; by chelating calcium, sodium citrate prevents clot formation, allowing for accurate measurement of various coagulation parameters such as PT (prothrombin time) and aPTT (activated partial thromboplastin time).

Sodium citrate is preferred in laboratory settings because it maintains the stability of coagulation factors, ensuring reliable and consistent test results. The typical concentration of sodium citrate used is 3.2% or 3.8%, and it is generally mixed in a 9:1 ratio with blood to achieve optimal anticoagulation for testing purposes.

While other anticoagulants like EDTA, heparin, and oxalate serve important functions in different types of tests, they are not the standard for coagulation tests. EDTA is more suitable for hematological analyses, heparin is often used in certain emergency situations or for specific assays, and oxalate is typically used for glucose tests. Understanding the specific applications of various anticoagulants is essential for proper laboratory practices and accurate diagnostics.