Also Known As
Lanoxin, Lanoxin-PG
Formal Name
This article was last reviewed on
This article waslast modified on 25 September 2018.
At a Glance
Why Get Tested?

To determine if the amount of digoxin in your blood is at an appropriate level or to detect potentially toxic levels

When To Get Tested?

Soon after the start of digoxin therapy and at regular intervals to ensure that drug levels are within the desired range and are not low or at toxic concentrations

Sample Required?

A blood sample collected from a vein in your arm

Test Preparation Needed?

No special preparation is needed, but timing of the sample for testing is important. When you have your blood taken, tell the healthcare professional when you took your last dose of digoxin. You may want to write down the exact time at which you took your dose and when the blood was taken. This information will be useful if your doctor has any questions about your results.

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Digoxin is a drug used to treat abnormal heart rhythms and severe heart failure. This test measures the amount of digoxin in the blood.

Digoxin slows the heart rate and helps to control abnormal heart rhythms know as arrhythmias. Heart failure, including congestive heart failure (CHF) causes the heart to become less effective at circulating blood around the body.  As a result, blood accumulates in the legs, hands, feet, lungs and liver, causing swelling, shortness of breath, and fatigue. Digoxin is used to reduce some symptoms of heart failure. It strengthens the contractions of the heart and helps it to pump blood more efficiently.

Digoxin will not cure arrhythmias or heart failure, which are long term conditions, but can, along with diet, exercise, and other medicines, help to manage the symptoms.

Digoxin levels need to be monitored because digoxin is a drug that has a narrow safety range. If the level in the blood is too low, symptoms may recur. If the level is too high, side effects may occur, such as:

  • dizziness
  • blurred vision or seeing yellow or green halos
  • nausea and vomiting
  • diarrhoea
  • irregular heartbeat
  • difficulty breathing
  • rash

The amount of digoxin you are prescribed may be adjusted based on the results of your blood test.

How is the sample collected for testing?

A blood sample is collected by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No special preparation is needed, but timing of the sample for testing is important. When you have your blood taken, tell the healthcare professional when you took your last dose of digoxin. You may want to write down the exact time at which you took your dose and when the blood was taken. This information will be useful if your doctor has any questions about your results.

Accordion Title
Common Questions
  • How is it used?

    A digoxin test is requested by your doctor to measure the amount of digoxin that is present in your blood. The dose of digoxin prescribed by your doctor may be adjusted depending on the result of your blood test. Your doctor may want to measure digoxin at regular intervals to ensure that an appropriate level is maintained, especially if your kidney function changes as the drug is excreted through the kidneys.

  • When is it requested?

    The test to measure digoxin is requested at the beginning of drug treatment to ensure correct dosage. Digoxin takes approximately one to two weeks to reach a steady level in the blood and in the heart. A test done at the right time will be a better indication of whether you are receiving the right amount of digoxin. Digoxin levels will then be measured at a frequency decided by your doctor to maintain the right dose, or if any changes occur in the type of tablet, the dose or other medicines taken at the same time. Changes in your health can also affect levels of digoxin and its ability to control your symptoms. Some physiological changes that may affect levels of digoxin in the blood are:

    • kidney function
    • thyroid problems
    • cancer
    • stomach or intestinal illness

    Digoxin will not cure heart failure but will help to control it. Since digoxin is prescribed to treat patients with a long-term, chronic condition, it is usually monitored throughout the treatment.

    Timing of the digoxin blood test is important. The sample should be collected at least 6-8 hours after you last took your digoxin. Very often, the blood sample will be collected just before the next dose is to be taken. Timing of the sample collection is important because if the sample is collected too soon after the drug is taken, the results of the test could be misleading and may appear to be toxic (very high) when this is not the case. This is because digoxin needs to distribute through the body after a dose has been taken, and specimens taken within the first six hours do not give enough time for this distribution to take place.

  • What does the test result mean?

    The appropriate (“target”) range for digoxin has been established over time as 0.5-2.0 µg/L for patients being treated for heart failure. Several newer studies suggest a narrower range, 0.5-1.0 µg/L, may be appropriate for some patients. The recommended range for patients with a/node/264 is 1.5-2.0 µg/L. Most patients find that their symptoms improve when their digoxin results are within this range.

    It is important to note that each patient’s response to medicines is individual and other factors such as kidney function or other drugs taken at the same time may be important. If your symptoms have not improved or if you have side effects, tell your doctor immediately. He/she may need to change your dose to meet your individual needs.

    If your result does not fall within the “target” range but you are not experiencing symptoms, continue to take your medication as prescribed until you consult with the doctor who requested the test. He/she will evaluate your case and decide if it is necessary to adjust your dose. If your dose needs to be adjusted, your doctor may request further digoxin tests to determine the resulting blood level.

  • Is there anything else I should know?

    Several prescribed and over-the-counter drugs can affect the level and effectiveness of digoxin in your system. Be sure to tell your doctor about all other medicines you may be taking.

    Digoxin is mainly removed from your blood by the kidneys. Tell your doctor if you have, or have had, kidney problems. Your doctor may want to measure blood potassium levels since low levels of potassium can result in symptoms of toxicity.

    If toxic levels are found, reducing the dose of digoxin or stopping the drug for a short time is sufficient to bring levels back to normal quickly. In severe cases where highly toxic levels of digoxin are measured, anti-digoxin antisera may be given to reverse the effects of the drug.

  • How long will I need to be on digoxin?

    Digoxin is usually taken for your lifetime, although it may be stopped under close medical supervision in some cases.

  • Who requests digoxin tests?

    Your general practitioner may request the test, but it also may be requested by a hospital cardiologist.

  • Can I test my digoxin level at home?

    No, there are no home tests developed. Digoxin sample requires special handling and laboratory instruments, in order to generate accurate results