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Digoxin Immunoassay, Plasma

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

This test measures the amount of digoxin, a medication used to treat certain heart conditions, in your blood plasma.

Quick summary

["Digoxin levels help doctors monitor your heart health while you’re taking this medication."]

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

Key facts at a glance

LOINC
73418-6
Short code
Digoxin ind plt IgG SerPl Ql FC
Synonyms
Digoxin ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.5
Ref high
2
Critical range
— – 4 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 Is This Test Done?

Your doctor may order this test to check if your digoxin levels are within the safe range. Too much or too little can affect your heart rhythm and cause side effects. It’s often done regularly if you’re taking digoxin long-term.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab where it’s analyzed using an immunoassay method to detect digoxin levels.

What Are Common Results?

Results are typically reported in nanograms per milliliter (ng/mL) or micrograms per liter (µg/L). Your doctor will interpret the results based on your medical history and symptoms.

What Might Affect Results?

Several factors can influence digoxin levels, including other medications you’re taking (like certain antibiotics or diuretics), kidney function, and how your body processes the drug.

Reference range

Therapeutic: 0.5-2.0 ng/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Digoxin Level (Plasma)

Frequently asked questions

How often should I expect this test?
Your doctor will schedule follow-up tests based on your treatment plan and how your body responds to digoxin. Typically, tests are done at regular intervals (e.g., every few weeks) to monitor your levels.
What are the normal ranges for this test?
There isn’t a single ‘normal’ range for everyone. Your doctor will use your specific needs, symptoms, and medical history to determine what’s appropriate for you.
Can I eat or drink before this test?
You can usually eat and drink normally before this test, unless your doctor instructs otherwise. However, avoid alcohol and certain medications that might affect digoxin levels.
  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