PT/INR aPTT Flashcards
A patient is ordered a PT/INR blood test. As the nurse you know that this blood test assesses?
A. Extrinsic pathway of coagulation and common pathways
B. Intrinsic pathway of coagulation and common pathways
C. Clotting factors XII, XI, IX, VIII
D. Only clotting factor II (prothrombin)
A: Extrinsic pathway of coagulation and common pathways. The PT/INR assesses the extrinsic pathway of coagulation (which uses clotting factor VII) and common pathways (which uses factor I, II, V, X). The extrinsic pathway is activated when there is outside/external injury that results in blood loss from the vascular system.
Your patient is being evaluated for a bleeding disorder. The physician orders an aPTT blood test. Which statement is TRUE about this coagulation test?
A. The aPTT is an important result used to assess the effectiveness of Warfarin.
B. The aPTT assesses the intrinsic pathway of coagulation and common pathways.
C. The aPTT is measured in milliseconds.
D. The aPTT only assesses clotting factor VII.
The aPTT assess the intrinsic pathway of coagulation and common pathways. The aPTT assesses the intrinsic pathway of coagulation and common pathways. Therefore, clotting factors I, II, V, X (which are part of common pathways) and clotting factors XII, XI, IX, VIII (which are part of intrinsic pathway) are assessed. The intrinsic pathway is activated when there is inside injury within the vascular system. The aPTT is an important result used to assess the effectiveness of Heparin (NOT Warfarin), and it’s measured in SECONDS (not milliseconds).
What is the approximate normal range for an aPTT result?
A. 2-3 second
B. 30-40 seconds
C. 1.5-2.5 times the normal range
D. 10-12 seconds
B: 35-45 seconds (This range varies among labs).
A patient is receiving continuous IV Heparin. In order for this medication to have a therapeutic effect on the patient, the aPTT should be?
A. 0.5-2.5 times the normal value range
B. 2-3 times the normal value range
C. 1.5-2.5 times the normal value range
D. 1-3.5 times the normal value range
An aPTT should be 1.5-2 times the normal value range for Heparin to achieve a therapeutic effect in a patient to prevent blood clots. If the aPTT is too low, blood clots can form. If the aPTT is too high, bleeding can occur.
A patient is prescribed Warfarin (Coumadin) for the treatment of a blood clot. What is the therapeutic INR range for this medication to be effective?
A. 2-3
B. 1-3
C. 4-8
D. 0.5-2.5
The answer is A. The therapeutic INR range is 2-3. It may be slightly higher if a patient is at a high risk for clot formation….(ex: up to 4.5)
What is an approximate normal range for a PT (prothrombin) level?
A. 10-12 seconds
B. 2-3 seconds
C. 30-40 seconds
D. 60-80 seconds
The answer is A: 10-12 second
Your patient, who is prescribed Warfarin for blood clots, has an INR of 1. As the nurse you know that this means?
A. The medication is therapeutic.
B. The medication is not effective at preventing blood clots.
C. The patient is at risk for bleeding.
D. The patient is experiencing Warfarin toxicity.
The answer is B. A therapeutic INR for a patient taking Warfarin should be 2-3. Therefore, the patient’s medication is not effective at this time for preventing blood clots
Fill in the blank: Prothrombin turns into _________ with the assistance of clotting factor V.
A. fibrinogen
B. fibrin
C. thrombin
D. vitamin K
The answer is C: Thrombin….Prothrombin turns into thrombin by clotting factor V. When thrombin is on board it is responsible for turning fibrinogen to fibrin. Fibrin is one of the main ingredients for clot formation.
A patient’s PT result is 30 seconds. What conditions below could cause this result? Select all that apply:
A. None, this is a normal PT range.
B. Vitamin K deficiency
C. Liver disease
D. Warfarin
The answers are B, C, and D. All of these could increase the PT level (a normal range is approximately 10-12 seconds).
Your patient’s aPTT level is 32 seconds. The nurse would interpret this lab result as?
A. Too high, the patient is at risk for bleeding.
B. Too low
C. Normal
The answer is C: Normal…an approximate normal range for an aPTT is about 35-45 seconds.
