Therapeutic digoxin monitoring, dig level
This test measures the amount of the heart drug digoxin in your blood.
Digoxin is a drug that helps your heart pump better when you have an irregular or rapid heartbeat. This heartbeat is often caused by atrial fibrillation. Digoxin may also be given to you if you have congestive heart failure (CHF).
When you take digoxin, it's important that the drug be at the right level for you to get the help you need from it. Your healthcare provider may need to change your dose if your levels are too high or too low.
You may need this test to have your digoxin level checked when you first start treatment. This is to make sure you are taking the right dose. The dose level that works best for most people may be called the therapeutic range. A digoxin dose is not the same for everyone, so your healthcare provider may need to change your dose over time.
You may need this test to:
Find your therapeutic dose of digoxin after you begin taking the drug
Check the drug level regularly to make sure you keep getting a therapeutic dose
See whether certain symptoms you are having may be related to your digoxin level
Your healthcare provider may also order other tests if you have signs or symptoms that may mean your digoxin level is too high or too low. These tests include an electrocardiogram, or ECG. Your provider may also order tests to check your kidney health if you have kidney problems. He or she may also order tests to check your blood potassium and magnesium levels. Kidney problems and low levels of potassium or magnesium in the blood may lead to digoxin overdose.
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.
Results are given in nanograms per milliliter (ng/mL).
If you are taking digoxin because of an irregular heartbeat, your ideal range may be between 1.5 and 2.5 ng/mL. But this range varies widely. This is because the test is more commonly used to check for toxicity when treating an irregular heart beat instead of to find out how well the drug is working as a treatment.
If you have CHF, the ideal range may be lower. When used for CHF, the target range for this test is important to find out both how well the drug is working as treatment and to avoid the risk for toxicity.
If your digoxin level is outside the therapeutic range, your healthcare provider may raise or lower your digoxin dose.
If you have CHF and your digoxin levels are below the normal treatment range, you may develop symptoms of persistent heart failure:
Fluid buildup in your lungs or your legs
Shortness of breath
Changes in your heartbeat
Digoxin levels above the normal treatment level may cause:
Nausea or vomiting
Blurred or yellow-tinted vision
Very high levels of digoxin can cause a condition called digoxin toxicity. This may require treatment with a medicine to block the effects of digoxin. Digoxin side effects can occur even when levels are considered to be within normal limits. It's important to report any new symptoms to your healthcare provider.
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
Taking digoxin within 6 to 12 hours before this test can affect your results.
Many other medicines can also affect your digoxin level. These include antacids, drugs that lower cholesterol, over-the-counter medicines for diarrhea, bulk laxatives, and nutritional supplements. Foods high in fiber can also affect your results.
Ask your healthcare provider when you should stop taking digoxin before the test. In addition, make sure your provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.