Does this test have other names?

Therapeutic digoxin monitoring, dig level

What is this test?

This test measures the amount of the heart medicine digoxin in your blood.

Digoxin is a medicine 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 medicine is 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.

Why do I need this test?

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 is 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 medicine

• Check the medicine 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

What other tests might I have along with this test?

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 healthcare provider may also order tests to check your kidney health if you have kidney problems. They 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.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Results are given in nanograms per milliliter (ng/mL).

If you are taking digoxin because of an irregular heartbeat, your therapeutic range may be between 1.0 and 2.0 ng/mL. But this range varies widely. This is because the test is more commonly used to check for toxicity when treating an irregular heartbeat instead of to find out how well the medicine 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 medicine 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

• Tiredness (fatigue)

Digoxin levels above the normal treatment level may cause:

• Nausea or vomiting

• Diarrhea

• Stomach pains

• Fainting

• Dizziness

• Changes in your heartbeat

• Confusion

• Blurred or yellow-tinted vision

Very high levels of digoxin can cause a condition called digoxin toxicity. This may need treatment with a medicine to block the effects of digoxin. Digoxin side effects can happen even when levels are considered to be within normal limits. It's important to report any new symptoms to your healthcare provider.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

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, medicines that lower cholesterol, over-the-counter medicines for diarrhea, bulk laxatives, and nutritional supplements. Foods high in fiber can also affect your results.

How do I get ready for this test?

Ask your healthcare provider when you should stop taking digoxin before the test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any street drugs you may use.