Which laboratory test measures the effectiveness of warfarin?
PTT.
PT/INR.
aPTT.
ACT.
The Correct Answer is B
PT stands for prothrombin time, which is a measure of how long it takes the blood to clot.
INR stands for international normalized ratio, which is a way of standardizing the PT results across different laboratories.
Warfarin is a blood thinner that works by inhibiting the production of vitamin K-dependent clotting factors in the liver.
Therefore, warfarin prolongs the PT and increases the INR. The PT/INR test is used to monitor the effectiveness of warfarin therapy and adjust the dose accordingly.
Choice A is wrong because PTT stands for partial thromboplastin time, which is another measure of blood clotting time, but it reflects the activity of different clotting factors than PT. PTT is used to monitor heparin therapy, not warfarin therapy.
Choice C is wrong because aPTT stands for activated partial thromboplastin time, which is a variation of PTT that uses an activator to speed up the clotting time. Like PTT, aPTT is used to monitor heparin therapy, not warfarin therapy.
Choice D is wrong because ACT stands for activated clotting time, which is a measure of the whole blood clotting time. ACT is used to monitor high-dose heparin therapy during certain procedures, such as cardiac bypass surgery or angioplasty.
The normal ranges for these tests may vary depending on the laboratory and the method used, but generally, they are:
• PT: 10 to 13 seconds
• INR: 0.8 to 1.2 (without warfarin) or 2.0 to 3.0 (with warfarin)
• PTT: 25 to 35 seconds
• aPTT: 30 to 40 seconds
• ACT: 70 to 120 seconds
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Erectile dysfunction drugs should not be used when a patient is taking nitrates.This is because both types of drugs cause blood vessels to dilate, which can lead to a dangerous drop in blood pressure. This can increase the risk of heart attack, stroke or fainting.
Choice B is wrong because alpha-adrenergic blockers are sometimes used together with nitrates to treat high blood pressure and angina. They work by relaxing the smooth muscles of the blood vessels, which lowers blood pressure and improves blood flow.
Choice C is wrong because calcium channel blockers are also used to treat high blood pressure and angina. They work by blocking the entry of calcium into the muscle cells of the heart and blood vessels, which reduces the force of contraction and relaxes the blood vessels.
Choice D is wrong because beta-adrenergic blockers are another class of drugs that can be used with nitrates to treat high blood pressure and angina. They work by blocking the effects of adrenaline on the heart and blood vessels, which slows down the heart rate and lowers blood pressure.
Normal ranges for blood pressure vary depending on age, gender and other factors, but generally they are between 90/60 mmHg and 120/80 mmHg for healthy adults.
Correct Answer is C
Explanation
Anticoagulants are medicines that increase the time it takes for blood to clot.They do not dissolve existing clots, but they can stop them from getting bigger or prevent new clots from forming.Anticoagulants work by interfering with different steps of the blood coagulation pathway, which is a complex process that involves many clotting factors.
Choice A is wrong because anticoagulants do not dissolve existing clots.To dissolve clots, you need medicines called thrombolytics or fibrinolytics, which break down the fibrin that holds the clots together.
Choice B is wrong because anticoagulants do not transport platelets.
Platelets are blood cells that help with clotting by sticking together and forming a plug at the site of an injury.Anticoagulants may affect the function of platelets, but they do not move them around.
Choice D is wrong because anticoagulants do not increase blood viscosity.
Viscosity is a measure of how thick and sticky a fluid is.
Anticoagulants are sometimes called blood thinners, but they do not actually change the viscosity of blood.They just make it less likely to clot.
Normal ranges for blood clotting tests vary depending on the type of test and the laboratory that performs it.
Some common tests and their normal ranges are:
• Prothrombin time (PT): 11 to 13.5 seconds
• International normalized ratio (INR): 0.8 to 1.2
• Activated partial thromboplastin time (aPTT): 25 to 35 seconds
• Anti-factor Xa: 0.3 to 0.7 units/mL
• D-dimer: less than 0.5 mcg/mL
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.