Diphtheria IgG Antibody, Serum (Quantitative Immunoassay)
This test measures the level of antibodies your body produces in response to the diphtheria infection. Antibodies help your immune system recognize and fight the bacteria that cause diphtheria.
["Your immune response to diphtheria infection is tracked to ensure protection."]
Key facts at a glance
- LOINC
- 109144-6
- Short code
- DIPIGG
- Synonyms
- C diphtheriae IgG Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) - red/gray top, or plain red top tube
- Units
- N/A
- Ref low
- 0.1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Enzyme Immunoassay (EIA) / Chemiluminescent Immunoassay (CLIA)
- CPT
- 86317
- SNOMED
- 313381002
- Specimen volume
- 0.5-1 mL serum (minimum 0.3 mL)
- Stability
- Stable for 7 days at 2-8°C; for extended storage, freeze at -20°C or below for up to 6 months. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 200
- Lipemia max
- 100
- Icterus max
- 40
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test to check if you have enough immunity against diphtheria, especially if you’ve received vaccines or have been exposed to the bacteria. It can also help confirm if you’ve had prior exposure or infection, though it won’t detect an active infection at the time of testing.
How the Test Works
A small blood sample is taken from your arm and sent to a lab. The lab uses an immunoassay method to detect and measure the specific antibodies (IgG) your immune system produces against diphtheria toxins. This helps determine your level of immunity.
Sample Collection
A healthcare provider will clean your arm with an antiseptic, insert a needle into a vein, and collect about 5–10 milliliters of blood. The process usually takes a few minutes. You may feel a brief pinch, but most people don’t experience significant discomfort.
What to Expect Before the Test
No special preparation is needed for this test. You can eat, drink, or take your usual medications as usual. If you’re on blood-thinning medications, let your provider know before the test.
Reference range
Negative: <0.1 IU/mL; Equivocal: 0.1-0.3 IU/mL; Positive: >0.3 IU/mL. Protective immunity generally considered at levels ≥0.1 IU/mL.N/A
No special preparation required. Specimen should be collected prior to administration of diphtheria toxoid vaccine if possible, or at least 4 weeks post-vaccination for accurate immune status assessment.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Diphtheria Antibody Test
Frequently asked questions
How long does it take to get results?
What does a low or high antibody level mean?
Can this test detect an active diphtheria infection?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 14, 2026. · Read our editorial policy