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

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of a heart medication called digoxin in your blood. Digoxin helps control heart rhythm and fluid buildup in the body.

Quick summary

["Digoxin levels help ensure your medication dose is safe and effective for your heart health."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
102558-4
Short code
False ragweed IgE RAST
Synonyms
False ragweed IgE RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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 healthcare provider may order this test if you’re taking digoxin to treat certain heart conditions, such as irregular heartbeats (arrhythmias) or heart failure. They may also check it if you have symptoms like nausea, vomiting, or unusual fatigue, which could signal a drug level that’s too high or low.

How the Test Works

A blood sample is taken from a vein in your arm. The lab then uses a sensitive test to measure the amount of digoxin in your serum or plasma. The result helps determine if your dose is working as intended.

What to Expect Before the Test

No special preparation is usually needed, but let your provider know if you’re taking other medications, have allergies, or are pregnant. Avoid eating or drinking anything for 8–12 hours before the test if instructed.

What to Expect During the Test

You’ll lie down comfortably while a healthcare professional inserts a needle into your arm. A small amount of blood is drawn into a tube. The process usually takes a few minutes and may cause a slight pinch or sting.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Digoxin Level

Frequently asked questions

What does a ‘normal’ result mean?
There’s no single ‘normal’ range for digoxin because it varies based on your health, age, and other medications. Your provider will compare your result to your specific needs and adjust your treatment plan accordingly.
How often should I get this test?
Your provider will determine how often you need this test. For most patients, it’s done every few weeks or months to monitor your dose. Follow their instructions closely.
Can I eat or drink before the test?
Typically, you should fast for 8–12 hours before the test unless your provider gives other instructions. Avoid caffeine or alcohol in that time to ensure accurate results.
  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 17, 2026. · Read our editorial policy