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Serum IgG antibody to *Coccidioides* (IgG antibody to *Coccidioides* antigen)

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

This test measures the level of antibodies in your blood that your immune system produces in response to *Coccidioides* (a fungal infection found in certain regions).

Quick summary

["Helps diagnose or monitor *Coccidioidomycosis* (valley fever)."]

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

Key facts at a glance

LOINC
27009-0
Short code
Coccidioides IgG Ser-aCnc
Synonyms
Coccidioides IgG Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is Done

Your healthcare provider may order this test if you live in or have traveled to an area where *Coccidioides* is common, or if you have symptoms like fever, cough, or fatigue. It can also be used to check if treatment is working or if the infection has returned.

What to Expect Before the Test

No special preparation is needed. You’ll have a blood sample drawn from a vein, usually in your arm. It may feel slightly uncomfortable for a few seconds, but it shouldn’t last long.

What the Test Results Mean

Positive results indicate your immune system has detected *Coccidioides* antigens, suggesting past or current infection. Higher levels may mean active disease. Results alone don’t confirm diagnosis—your doctor will consider symptoms, medical history, and other tests.

Possible Side Effects

Most people experience only mild discomfort at the injection site. Rarely, bruising or swelling may occur. If you have a bleeding disorder or take blood thinners, let your provider know.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

IgG Antibody to Coccidioides

Frequently asked questions

What does a high level of IgG antibody mean?
A high IgG antibody level strongly suggests past or current *Coccidioidomycosis*. It’s often used alongside clinical findings (like symptoms or imaging) to diagnose the infection. However, false positives can occur in people who’ve been exposed but haven’t developed symptoms.
Why might my IgG antibody level be low?
Low levels could mean the infection is no longer active, your immune system is suppressing it, or you’ve had treatment. If you’re recovering, your body may naturally reduce antibody production over time.
How often should I get retested?
Your provider will determine retesting frequency based on your symptoms, treatment plan, and risk factors. For example, if you’re treated for active infection, follow-up tests may be needed to monitor response or recurrence.
  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