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Chlamydia trachomatis Serology (IgG Antibody) – Qualitative

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

This test detects antibodies to *Chlamydia trachomatis*, a bacterium that can cause infections like chlamydia, pelvic inflammatory disease, or complications in pregnancy. It helps identify past exposure, not current infection.

Quick summary

["This test checks for past exposure to chlamydia, not an active infection."]

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

Key facts at a glance

LOINC
77166-7
Short code
Chlamydia sp IgG+IgM Pnl Titr Ser IF
Synonyms
Chlamydia sp IgG+IgM Pnl Titr Ser IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 doctor may order this test if you have symptoms of chlamydia (e.g., unusual discharge, pain during urination) or if you’ve been exposed to the bacteria. It’s also used in screening for sexually transmitted infections (STIs) or during pregnancy to assess risk.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample (serum or plasma) via a simple venipuncture. Avoid alcohol or certain medications for 24 hours before testing if instructed by your provider.

What the Test Results Mean

A positive result means your body has produced antibodies against *Chlamydia trachomatis*, indicating past exposure. A negative result suggests no detectable antibodies at the time of testing. Results alone don’t confirm current infection—confirmatory testing (e.g., nucleic acid amplification) may be needed.

When You Might Need Follow-Up

If you test positive, follow your doctor’s advice for treatment (often antibiotics) and retesting. If symptoms persist or you’re pregnant, additional testing may be recommended to rule out other infections or complications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Chlamydia IgG Antibody (Serum/Plasma)

Frequently asked questions

What does a positive result mean for my health?
A positive result indicates your body has been exposed to *Chlamydia trachomatis* at some point, but it doesn’t confirm whether you had an active infection. This test is primarily used to screen for past exposure, not to diagnose current infection. Treatment is directed by your doctor based on symptoms, risk factors, and other diagnostic tests.
Can this test be used to diagnose an active chlamydia infection?
No, this qualitative antibody test detects past exposure. For diagnosing an active infection, your doctor may use nucleic acid amplification tests (e.g., PCR) on urine, cervical, or vaginal swabs. These tests are more sensitive for current infection.
How long after exposure might I test positive?
Antibodies develop gradually after exposure. A positive result may take weeks to months to appear, depending on the timing of testing relative to exposure. If you suspect recent exposure, confirmatory testing (e.g., PCR) is recommended for active infection detection.
  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