AACN Certification Practice Test 2025 – Comprehensive Exam Prep

The effectiveness of the blood's ability to clot is primarily measured by coagulation tests, with the International Normalized Ratio (INR) and Prothrombin Time (PT) being key indicators. Both of these tests assess the same aspect of clotting, specifically focusing on the extrinsic and common pathways of coagulation.

The PT test measures the time it takes for blood to clot after a tissue factor is introduced, reflecting the levels of several clotting factors. The INR, on the other hand, is a standardized way to express PT results, allowing for consistent interpretation of blood clotting ability regardless of testing variations between different laboratories. The INR is especially significant for patients on anticoagulant medications, ensuring that their clotting levels remain within a therapeutic range.

As both the INR and PT provide crucial information about the clotting ability of the blood and are often used together in clinical settings, the correct answer acknowledges the relevance of both tests in evaluating coagulation effectiveness.