Choose the group that is correct.
Select all that apply.

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 standardized way of reporting the PT result. Warfarin is a blood thinner that works by slowing down the clotting process.Therefore, people who take warfarin need to have their PT/INR monitored regularly to make sure they are getting the right dose and not bleeding too much or too little.

Choice A is wrong because PTT stands for partial thromboplastin time, which is another measure of blood clotting that is not affected by warfarin.PTT is used to monitor heparin, another type of blood thinner.

Choice C is wrong because CBC stands for complete blood count, which is a test that measures the number and types of cells in the blood, such as red blood cells, white blood cells and platelets.CBC can show if there is anemia, infection or bleeding, but it does not measure the effect of warfarin on clotting.

Choice D is wrong because LFTs stand for liver function tests, which are a group of tests that check how well the liver is working.

LFTs can show if there is liver damage or disease, which can affect how warfarin is metabolized and cleared from the body.However, LFTs do not directly measure the effect of warfarin on clotting.

The normal range for PT/INR varies depending on the laboratory and the reason for taking warfarin.

Generally, the normal range for PT is 10 to 13 seconds, and the normal range for INR is 1.1 or below for healthy people.For people taking warfarin, the target INR range depends on their condition and risk factors, but it is usually between 2.0 and 3.0.

This is because low potassium levels (hypokalemia) increase the sensitivity of the heart to digoxin and can lead to toxicity even with normal serum digoxin levels. Digoxin inhibits the sodium-potassium pump on the cardiac cells, which causes potassium to accumulate outside the cells.Low potassium levels in the blood create a larger gradient for potassium to move out of the cells, which enhances the effect of digoxin and can cause arrhythmias.

Choice B is wrong because calcium 9.2 mg/dL is within the normal range (8.5 to 10.2 mg/dL) and does not increase the risk of digoxin toxicity.However, high calcium levels (hypercalcemia) can potentiate the effects of digoxin and cause toxicity.

Choice C is wrong because sodium 140 mEq/L is within the normal range (135 to 145 mEq/L) and does not increase the risk of digoxin toxicity.However, high sodium levels (hypernatremia) can reduce the binding of digoxin to the sodium-potassium pump and decrease its efficacy.

Choice D is wrong because magnesium 2.2 mg/dL is within the normal range (1.7 to 2.4 mg/dL) and does not increase the risk of digoxin toxicity.However, low magnesium levels (hypomagnesemia) can increase the sensitivity of the heart to digoxin and cause toxicity.