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 C
Explanation
This is because potassium sparing diuretics do not lower potassium levels in the blood, unlike other types of diuretics.Potassium is an essential electrolyte that serves nerve and muscular functions and is regulated by the kidneys.Low potassium levels can cause irregular heartbeats and other problems. Therefore, patients taking potassium sparing diuretics should avoid food sources that are high in potassium, such as bananas, avocados, spinach, and potatoes.
Choice A is wrong because thiazide diuretics, such as hydrochlorothiazide, can cause low potassium levels in the blood.
Patients taking thiazide diuretics may need to take potassium supplements or eat more potassium-rich foods to prevent hypokalemia.
Choice B is wrong because osmotic diuretics, such as mannitol, do not affect potassium levels in the blood.
They work by increasing the amount of water in the urine, but do not alter the electrolyte balance.
Osmotic diuretics are mainly used to treat cerebral edema and glaucoma.
Choice D is wrong because loop diuretics, such as furosemide, can also cause low potassium levels in the blood.
They work by inhibiting the reabsorption of sodium and water in the loop of Henle, a part of the kidney.
Loop diuretics are used to treat edema and heart failure.
Normal ranges for potassium in the blood are 3.5 to 5.0 millimoles per liter (mmol/L).
Correct Answer is A
Explanation
Intermittent claudication is a condition where leg pain is produced upon increased activity and ischemia to tissues, but then the pain is reduced with rest.This is because the lack of oxygen to the muscles causes pain, and resting allows the blood flow to resume.
Choice B, sporadic ischemia, is wrong because it is not a specific condition, but a general term for reduced blood supply to a tissue or organ.
Choice C, angina, is wrong because it is a chest pain caused by reduced blood flow to the heart, not the legs.
Choice D, paresthesia, is wrong because it is a sensation of tingling, numbness, or prickling in the skin, not pain.
It can be caused by various conditions, such as nerve damage, diabetes, or Raynaud’s disease.
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