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Serum/Plasma Bacterial Antigen (e.g., *Listeria monocytogenes*, *Salmonella spp.*, *Shigella spp.*)

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

This test checks for the presence of specific bacteria in your blood or serum, often used to identify infections before cultures grow.

Quick summary

["Early detection of bacterial infections with blood or serum samples."]

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

Key facts at a glance

LOINC
33598-4
Short code
ENA SS-B IgG Ser IB-aCnc
Synonyms
ENA SS-B IgG Ser IB-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ib
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

What This Test Measures

The test detects bacterial antigens—small molecules produced by certain bacteria—using an immunoassay method. This helps identify infections like those caused by *Listeria*, *Salmonella*, or *Shigella* before traditional bacterial cultures confirm them.

How the Test Works

Your blood or serum is analyzed for specific bacterial antigens. If present, the test detects them through a chemical reaction that signals infection, often within hours rather than days.

When This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like fever, chills, or signs of infection (e.g., abdominal pain, diarrhea) and bloodwork suggests possible bacterial infection.

Common Uses and Limitations

This test is useful for rapid screening but isn’t definitive. It may be used alongside cultures to confirm or narrow suspected bacterial infections. False positives or negatives can occur, so results should be interpreted with clinical context.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Bacterial Culture Screening

Frequently asked questions

Why might I need this test?
To quickly identify bacterial infections in your blood or serum that may not yet show up in standard blood tests. It can help guide treatment decisions, especially in cases where cultures take longer to grow.
What does a positive result mean?
A positive result suggests the presence of specific bacterial antigens, which may indicate an infection. However, further testing (like cultures) is often needed to confirm the exact bacteria and guide treatment.
Can I eat or drink before this test?
Typically, fasting is not required, but follow your provider’s instructions. If drawn from blood, avoid strenuous activity before the test.
  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