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Chlamydia Antibody Panel, IgM by IFA

Chlamydia IgM Ab, CT IgM Ab

Test Codes

EPIC: LAB6236, Beaker: XCHLM, ARUP #65105

Department

Send Outs

Instructions

• This panel includes:
  • C. pneumoniae IgM.
  • C. psittaci IgM.
  • C. trachomatis IgM.
• Acute and convalescent specimens must be labeled as such; parallel testing is preferred and convalescent specimens must be received within 30 days from receipt of the acute samples. Please mark sample plainly as "acute" or "convalescent."

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells within two hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.4 mL)

Rejection Criteria

• Hyperlipemic specimens.
• Hemolyzed specimens.
• Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells within two hours of collection. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.4 mL)

Storage

After separation from clot:
Ambient: 2 days
Refrigerated: 14 days
Frozen: 1 year (avoid repeated freeze/thaw cycles)

Laboratory

Sent to ARUP Laboratories, Salt Lake City, UT.

Performed

Monday – Saturday.
Results available in 1-4 days.

Reference Range

By report.

Test Methodology

Semi-Quantitative Indirect Fluorescent Antibody (IFA).

Interpretation

The serological detection of chlamydial infections is complicated by the presence of cross-reactive antibody between Chlamydia species, non-specific stimulation of the anti-Chlamydia antibodies or past exposure to multiple Chlamydia species.

Early IgM response to infection may be distinguished from persistent low level titers by testing sera from patients 2-3 weeks later for changing levels of specific IgM antibodies.

The Chlamydial antibody test contains both species- and genus-specific antigens, and serological cross-reactions may be seen in both acute and convalescent samples (1:128). A C. pneumoniae-specific reaction will exhibit titers twofold or greater than titers observed with C. trachomatis or C. psittaci serology.

Note: The Chlamydia microimmunofluorescent assay slides utilize C. psittaci, C. pneumoniae, and 9 serotypes of C. trachomatis. It does not include the LGV strains of C. trachomatis.

C. trachomatis IgM determinations may be the method of choice in infants with chlamydial pneumonia. In adults, a single IgM antibody titer greater than or equal to 1:40 by microimmunofluorescence is suggestive of an active or recent chlamydial infection (1).

C. pneumoniae IgM usually appears three weeks after the onset of symptoms and antibody levels generally persist for 2-6 months. A single C. pneumoniae IgM antibody titer of greater than or equal to 1:20 suggests current or recent infection (1).

C. psittaci IgM is usually detectable at the onset of symptoms and antibody levels remain elevated for 1-2 months. A single IgM titer of greater than or equal to 1:40 is suggestive of an active or recent infection (1).

Note: Analytic Specific Reagents (ASRs) are used in many laboratory tests necessary for standard medical care and generally do not require FDA approval. This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the U.S. Food and Drug Administration. This test should not be regarded as investigational or for research use.

Clinical Utility

This assay aids in the differential diagnosis of Chlamydia infections. C. trachomatis is the leading cause of sexually transmitted disease in the U.S. with 3-5 million new cases occurring each year. There is no seasonal variation in the incidence of C. trachomatis infections (1).

C. pneumoniae is a respiratory tract pathogen that causes sporadic cases of pneumonia throughout the world. Seroepidemiologic surveys have shown that 30-50% of the general population has antibodies to C. pneumoniae. These antibodies are rarely seen in children below the age of 2 years, but the prevalence increases after 5 years of age. At 10 years of age, approximately 10% of the population has antibodies to C. pneumoniae and the prevalence plateaus at 30-50% by 30 years of age. Approximately 70% of persons over the age of 60 have antibody to C. pneumoniae (1).

C. psittaci causes sporadic disease and 40-60 psittacosis/ornithosis cases are reported annually in the U.S. Psittacosis has a worldwide distribution. Owners of pet birds, pet shop employees, and workers in turkey processing plants are at higher risk of acquiring the disease than the general population. Re-infections have been described. There is no record of infection acquired by handling dresses, eviscerated birds or by eating poultry products (1).

Reference

1. Wiedbrauk D, Johnston SLG. Manual of Clinical Virology, Raven Press, New York,NY, 1993.

CPT Codes

86632x3.

Contacts

Last Updated

7/3/2023