Skip to content

Serum/plasma mass concentration of diphtheria toxin-neutralizing antibodies

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

This test measures how well your immune system produces antibodies to protect against diphtheria, a serious bacterial infection.

Quick summary

["Checks your immunity to diphtheria after vaccination or exposure."]

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

Key facts at a glance

LOINC
77656-7
Short code
Dipl cells in S NFr Cells.XXX FC
Synonyms
Dipl cells in S NFr Cells.XXX FC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
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 to verify immunity after vaccination, assess exposure risk, or evaluate immune response in certain medical conditions.

What to Expect Before the Test

A simple blood draw is typically used. No special preparation is needed, but inform your provider about recent illnesses or medications.

How the Test Works

Blood is collected and analyzed to detect the presence and quantity of antibodies that neutralize diphtheria toxin, often using an immunoassay method.

Possible Results and Interpretation

Results indicate antibody levels, which help determine immunity status. High levels suggest adequate protection; low levels may require booster vaccination.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for confirming immunity in individuals at risk (e.g., children, travelers, or those with weakened immune systems). Low levels may prompt vaccination or further evaluation for immune deficiency.

Short name

Diphtheria Antibody Level

Frequently asked questions

What does a low antibody level mean?
A low level may mean your body isn’t fully protected against diphtheria. Your provider may recommend vaccination or monitoring.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on lab processing times.
Can I eat or drink before this test?
You can eat and drink normally unless instructed otherwise by your provider. No fasting is required.
  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