Skip to content

Digoxin Immunoassay (Plasma/Serum) – Quantitative

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.

Quick summary

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

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

Key facts at a glance

LOINC
73419-4
Short code
Digoxin ind plt IgM SerPl Ql FC
Synonyms
Digoxin ind plt IgM 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 This Test Is Done

Your healthcare provider may order this test if you’re taking digoxin (Lanoxin) to manage conditions like heart failure or irregular heart rhythms. It helps monitor whether your dose is too high or too low, preventing side effects like low heart rate or toxicity.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re on a strict diet or medication, let your provider know beforehand.

What the Test Results Mean

Results are compared to a general reference range, but exact values depend on your health and medication. High levels may indicate overdose or poor metabolism, while low levels may mean your dose isn’t working as intended.

Possible Side Effects or Risks

The blood draw is generally safe but may cause mild bruising, pain, or swelling at the site. Rarely, severe reactions like allergic responses can occur.

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

Frequently asked questions

Why might my doctor order this test?
Your doctor may order it to check if your digoxin dose is working properly, adjust it if needed, or detect toxicity from too much medication.
A high result may mean you’re at risk for side effects like heart rhythm problems or nausea. A low result might mean your dose isn’t controlling your heart condition effectively. Your doctor will interpret results with your specific health needs in mind.
You can eat and drink normally unless your doctor specifies otherwise. Some tests require fasting, but this one does not.
Frequency depends on your condition and medication. Some patients need it weekly or monthly, while others may only need it occasionally.
If you miss a dose, follow your doctor’s instructions. Do not skip the test unless advised, as it may affect the accuracy of 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