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Penicillin Antibody Screening (Plasma/Serum)

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

This test measures the presence of antibodies to penicillin in your blood, which may indicate a prior exposure or allergic reaction to this antibiotic.

Quick summary

["Assesses potential penicillin allergy risk before receiving penicillin-based treatment."]

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

Key facts at a glance

LOINC
73212-3
Short code
Penicillin ind plt IgM SerPl Ql FC
Synonyms
Penicillin ind plt IgM SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
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 Matters

Penicillin is a widely used antibiotic, but some people may develop an allergic reaction. This test helps determine if you have antibodies against penicillin, which could influence whether you’re at risk for an allergic response when taking the medication.

What to Expect Before the Test

No special preparation is needed. A blood sample will be taken from a vein in your arm. The test is typically done in a lab setting and results are usually available within a few days.

How the Test Works

The test detects specific antibodies in your blood that target penicillin. If these antibodies are present, it suggests you may have been exposed to penicillin before or could be more sensitive to it.

When This Test Might Be Ordered

Your doctor may recommend this test if you have a history of penicillin allergy, are about to start penicillin treatment, or if symptoms like rash, swelling, or difficulty breathing occur after taking penicillin.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Penicillin Antibody Test

Frequently asked questions

Your doctor will use the results to guide treatment decisions. Positive results may mean you should avoid penicillin or use alternative antibiotics carefully, while negative results suggest you can likely proceed with penicillin treatment without immediate concerns.
This test does not confirm a true allergy but helps assess risk. If you’ve had severe reactions in the past, further testing or allergy evaluation may be needed.
What does a positive result mean?
A positive result indicates the presence of penicillin antibodies, which may suggest a higher likelihood of an allergic reaction. However, not all positive results mean you cannot safely take penicillin; your doctor will evaluate your overall risk and recommend alternatives if needed.
Can I still take penicillin if my test is negative?
Yes, if your test is negative for penicillin antibodies, it is less likely you will have an allergic reaction. However, always inform your doctor about any past reactions or symptoms before starting any new medication.
  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