At a Glance
Why Get Tested?
To determine if the concentration of digoxin in your blood is at a therapeutic level or to detect toxic levels
When to Get Tested?
After the start of digoxin therapy and at regular intervals to ensure that drug levels are within therapeutic range (not low or at toxic concentrations)
A blood sample drawn from a vein in your arm
Test Preparation Needed?
No special preparation is needed, but timing of the sample for testing is important. When having your blood drawn, tell the laboratorian when you took your last dose of digoxin.
The Test Sample
What is being tested?
Digoxin is a drug used to treat heart failure and abnormal heart rhythms. This test measures the amount of digoxin in the blood. Heart failure, including congestive heart failure (CHF), causes the heart to become less effective at circulating blood. As a result, blood backs up into the legs, hands, feet, lungs and liver, causing swelling, shortness of breath, and fatigue.
Digoxin is prescribed to alleviate some symptoms of heart failure. It strengthens the contractions of the heart and helps it to pump blood more efficiently. Digoxin also helps control the heart rate and abnormal heart rhythms known as arrhythmias. It will not cure heart failure or arrhythmias, which are chronic conditions, but can help to manage the symptoms along with diet, exercise, and other medications.
Digoxin levels need to be monitored because digoxin is a drug with a narrow safety range. If the level in the blood is too low, symptoms may recur. If the level is too high, toxicity may occur.
Digoxin dosage may be adjusted based on levels measured.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
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 and your doctor may tell you to have your blood drawn a specific number of hours after your last dose of digoxin. When having your blood drawn, tell the laboratorian when you took your last dose. You may want to write down the exact time at which you took your dose and when the blood was drawn. This information will be useful if your doctor has any questions about your levels.
Ask a Laboratory Scientist
This form enables you to ask specific questions about your tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. If your questions are not related to your lab tests, please submit them via our Contact Us form. Thank you.
* indicates a required field
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 361-364.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 1334-1335.
(Revised 2010 January). What is Heart Failure? National Heart Lung and Blood Institute [On-line information]. Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/Hf/HF_WhatIs.html through http://www.nhlbi.nih.gov. Accessed February 2010.
A.D.A.M. Editorial Team (Updated 2009 February 3). Cardiac glycoside overdose. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/002581.htm. Accessed February 2010.
Dugdale, D. (Updated 2009 January 23). Digitalis toxicity. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000165.htm. Accessed February 2010.
Ahmed, A. (2008 May 21). An Update on the Role of Digoxin in Older Adults with Chronic Heart Failure. Medscape Today from Geriatrics & Aging 2008;11(1):37-41 [On-line information]. Available online at http://www.medscape.com/viewarticle/573855 through http://www.medscape.com. Accessed February 2010.
Patel, V. and James, P. (Updated 2010 January 6). Digitalis Toxicity. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/154336-overview through http://emedicine.medscape.com. Accessed February 2010.
Sources Used in Previous Reviews
A Manual of Laboratory & Diagnostic Tests. 6th ed. Fischbach F, ed. Philadelphia: Lippincott Williams & Wilkins; 2000.
Clinical Chemistry: Principles, Procedures, and Correlations. Bishop M, Duben-Engelkirk J, Fody E, eds. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2000.
Sacher RA, McPherson RA, Campos J. Widmann's Clinical Interpretation of Laboratory Tests. 11th ed. Philadelphia: F.A. Davis Company; 2000.
Goodman & Gilman's The Pharmacological Basis Of Therapeutics. 11th Edition. Lazo J, Goodman L S, Parker K L, eds, McGraw-Hill, September 2005.
National Heart, Lung, and Blood Institute (September 2003). Heart and Vascular Diseases: Heart Failure: Summary page (On line information). Available onlin at http://www.nhlbi.nih.gov/health/dci/Diseases/Hf/HF_All.html through http://www.nhlbi.nih.gov.
Terra, S G, Washam J B, Dunham, G D, and Gattis W A, (Oct 1999). Therapeutic Range of Digoxin's Efficacy in Heart Failure: What Is the Evidence? Pharmacotherapy, 19(10): 1123-1126, (On line journal). Available online at http://www.medscape.com/viewarticle/418044 through http://www.medscape.com.
Gibbs C R, Davies M K Davies, Lip G Y H, (Feb 2000). Management: Digoxin and other inotropes, Beta-blockers, and antiarrhythmic and antithrombotic treatment, BMJ. 320(7233): 495-498. PDF available for download at http://www.pubmedcentral.gov/articlerender.fcgi?tool=pmcentrez&artid=1127534 through http://www.pubmedcentral.gov.
Mihai Gheorghiade, MD; Kirkwood F. Adams, Jr, MD; Wilson S. Colucci, MD (2004). Digoxin in the Management of Cardiovascular Disorders, Circulation; 109:2959-2964 (On line journal). Available online through http://circ.ahajournals.org.
Rich, M. (2003 September). Drug Therapy of Heart Failure in the Elderly. Am J Geriatr Cardiol 12(4):235-242 (On line journal). Available online at http://www.medscape.com/viewarticle/460844 through http://www.medscape.com.
Yusuf, S (November 1997). Digoxin in heart failure: results of the recent digoxin investigation group trial in the context of other treatments for heart failure Eur Heart J, 18: 1685-1688. PDF available for download through http://eurheartj.oxfordjournals.org.
The Digitalis Investigation Group, (February 1997). The Effect Of Digoxin on Mortality and Morbidity in Patients with Heart Failure, NEJM volume 336:525-533 (On line journal). Available online at http://content.nejm.org/cgi/content/full/336/8/525 through http://content.nejm.org.
Catherine A. Hammett-Stabler, PhD, DABCC, FACB. Pathology and Laboratory Medicine, UNC-Chapel Hill.