Skip to content

Serum or plasma concentration of digoxin (or related cardiac glycoside)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of a heart medication called digoxin in your blood. Digoxin is used to treat certain heart rhythm problems and heart failure.

Quick summary

["Digoxin helps regulate your heart’s rhythm and strength; abnormal levels may cause serious health risks."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
25826-9
Short code
S aureus Etx D IgE Qn
Synonyms
S aureus Etx D IgE Qn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test to check if your digoxin dose is working properly, to monitor side effects, or to diagnose problems like low potassium (hypokalemia) or kidney issues that can affect how digoxin is processed in your body.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on digoxin, your doctor may ask you to stop taking it temporarily for a few days before testing to get an accurate reading.

What the Test Results Mean

High levels of digoxin can cause nausea, vomiting, irregular heartbeat, or vision changes. Low levels may mean your heart isn’t getting enough of the medication. Your doctor will interpret results based on your overall health and symptoms.

Common Causes of Abnormal Results

Factors like kidney disease, low potassium, or taking other medications (such as certain diuretics or heart medications) can alter digoxin levels. Other conditions, like liver disease or dehydration, may also play a role.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Digoxin Level

Frequently asked questions

How often should I get this test?
Your doctor will determine the frequency based on your treatment plan. For example, if you’re stable on digoxin, tests may be done every few weeks or months. If you’re unstable or have kidney issues, testing may be more frequent.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor instructs otherwise. Some tests may require fasting, but this test does not.
What are the risks of having this blood test?
The risks are minimal but may include a slight bruise, soreness, or a small bump at the injection site. Rarely, there could be a reaction to the needle or infection at the site.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy