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Vaccine-Specific Antibody Titer, 14 Days After Vaccination

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

A blood test that measures antibodies produced after vaccination, using a 14-day post-vaccination specimen.

Quick summary

["This test helps assess whether a vaccine has produced an immune response."]

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

Key facts at a glance

LOINC
97072-3
Short code
Vacc last 14 D
Synonyms
Vacc last 14 D
Category
liver
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
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

What is this test?

A vaccine antibody titer measures the amount of vaccine-specific antibodies in a blood sample. The 14-day designation generally indicates that the sample was collected 14 days after vaccination.

Why might I need this test?

This test may be used to assess immune response to a particular vaccine, especially in people with uncertain vaccination histories, weakened immune systems, or ongoing risk of infection.

How is the test performed?

A blood sample is collected and tested in a laboratory to determine the concentration of antibodies directed against the vaccine's target. The report identifies the vaccine or antibody measured and the laboratory's interpretation.

How do I prepare for the test?

Follow the timing instructions provided for the 14-day specimen collection. Tell your clinician which vaccine you received and when, because this information is needed to interpret the result correctly.

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

Vaccine antibody titer

Frequently asked questions

Does a positive result mean I am fully protected?
Not necessarily. Antibodies are one part of immune protection, and protection also depends on cellular immunity and the specific vaccine. Your clinician should interpret the titer with your medical history and risk factors.
Why is timing important?
Antibody levels can change after vaccination. Collecting the sample at the specified time, such as 14 days after vaccination, helps make the result more meaningful.
Can medications or health conditions affect the result?
Yes. Immunosuppressive medicines and conditions that weaken the immune system may reduce vaccine antibody responses. Share relevant medications and health conditions with your clinician.
  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