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Test Code CHLAP; SQ: CHLABS Chlamydia IgM and IgG Panel, Immunofluorescence, Serum


Ordering Guidance


For suspected Chlamydia trachomatis infection, order either CTRNA / Chlamydia trachomatis, Nucleic Acid Amplification, Varies or CGRNA / Chlamydia trachomatis and Neisseria gonorrhoeae, Nucleic Acid Amplification, Varies.



Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.6 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Secondary ID

619387

Useful For

Aiding in the clinical diagnosis of Chlamydia pneumoniae or Chlamydia psittaci infection

Highlights

This test includes testing for Chlamydia pneumoniae and Chlamydia psittaci.

Profile Information

Test ID Reporting Name Available Separately Always Performed
CHLG Chlamydia IgG, IFA, S Yes Yes
CHLM Chlamydia IgM, IFA, S Yes Yes

Method Name

Micro-Immunofluorescent Antibody (MIF) Assay

Reporting Name

Chlamydia IgM/IgG Panel, IFA, S

Specimen Type

Serum

Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 30 days
  Frozen  30 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject
Heat-inactivated specimen Reject

Clinical Information

Members of the family Chlamydiaceae are small, nonmotile, gram-negative, obligate intracellular organisms that grow in the cytoplasm of host cells. While there are at least 9 species within the Chlamydia genus, 3 are clinically significant, including Chlamydia trachomatis, Chlamydia pneumoniae and Chlamydia psittaci.

 

The chlamydial life cycle can be divided into 2 distinct phases: an extracellular, nonreplicating, infectious stage and an obligate intracellular, replicating, noninfectious stage. The infectious form, or elementary body (EB), attaches to the target cell membrane and enters the cell via a phagosome. After cell entry, the EB reorganizes into reticulate particles (forming inclusion bodies) and binary fission begins. After 18 to 24 hours, reticulate particles condense to form EBs. These new EBs are released, beginning another infection cycle.

 

C psittaci is the causative agent of psittacosis, a disease characterized by pneumonia, headache, altered mentation, and hepatosplenomegaly. Psittacosis is acquired by airborne transmission from infected birds.

 

C pneumoniae (formerly known as Taiwan acute respiratory agent and, more recently, as Chlamydophila pneumoniae) causes pneumonia in humans. It is unique because it is a primary pathogen of humans, is spread from human to human, and apparently has no animal or bird host. C pneumoniae is responsible for approximately 10% of pneumonia cases.

Reference Values

Chlamydia pneumoniae

IgM: <1:10

IgG: <1:64

 

Chlamydia psittaci

IgM: <1:10

IgG: <1:64

Interpretation

IgM

Chlamydia pneumoniae and Chlamydia psittaci

≥1:10

IgM endpoint titers of 1:10 or more are considered presumptive evidence of infection.

 

<1:10

IgM endpoint titers below 1:10 suggest that the patient does not have a current infection. These antibody levels may be found in patients with either no history of chlamydial infection or those with past infection whose antibody levels have dropped below detectable levels.

IgG:

C pneumoniae

≥1:512

IgG endpoint titers of 1:512 or more are considered presumptive evidence of current infection.

 

≥1:64 and <1:512

A single specimen endpoint titer of 1:64 to 1:512 should be considered evidence of infection at an undetermined time. A second specimen collected 10 to 21 days after the original collection should be tested in parallel with the first. If the second specimen exhibits a titer 1:512 or more or a 4-fold increase over that of the initial specimen, current (acute) infection is indicated. Unchanging titers from 1:64 to 1:512 suggest past infection.

 

<1:64

IgG endpoint titers below 1:64 suggest that the patient does not have a current infection. These antibody levels may be found in patients with either no history of chlamydial infection or those with past infection whose antibody levels have dropped below detectable levels.

 

C pneumoniae antibody is detectable in 25% to 45% of adults tested.

 

C psittaci

≥1:64

IgG endpoint titers of 1:64 or more are considered presumptive evidence of current infection.

 

<1:64

IgG endpoint titers below 1:64 suggest that the patient does not have a current infection. These antibody levels may be found in patients with either no history of chlamydial infection or those with past infection whose antibody levels have dropped below detectable levels.

Method Description

The microimmunofluorescent antibody assay is a 2-stage "sandwich" procedure. In the first stage, the patient serum is diluted in phosphate-buffered saline, added to appropriate slide wells in contact with the substrate, and incubated. After incubation, the slide is washed in buffered saline to remove unbound serum antibodies. In the second stage, each antigen well is overlaid with fluorescein-labeled antibody to IgG or IgM. The slide is incubated, allowing antigen-antibody complexes to react with the fluorescein-labeled anti-IgG. After the slide is washed, dried, and mounted, it is examined using fluorescence microscopy. Positive reactions appear as bright apple-green fluorescent elementary bodies with a background matrix of yolk sac. Semiquantitative endpoint titers are obtained by testing serial dilutions of positive specimens.(Schachter J. Chlamydiae [Psittacosis-Lymphogranuloma Venereum-Trachome Group]. In: Lennette E, Balows A, Hausler W, Shadomy H, eds. Manual of Clinical Microbiology. 4th ed. ASM Press; 1985: 856-861; Smith T. Chlamydia. In: Schmidt N, Emmons R, eds. Diagnostic procedures for viral, rickettsial and chlamydial infections. 6th ed. APHA; 1989: 1165-1198)

Day(s) Performed

Monday, Thursday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86632 x 2

86631 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CHLAP Chlamydia IgM/IgG Panel, IFA, S 77166-7

 

Result ID Test Result Name Result LOINC Value
619392 C. pneumoniae IgG In Process
619390 C. pneumoniae IgM In Process
619391 C. psittaci IgM In Process
619393 C. psittaci IgG In Process

Forms

If not ordering electronically, complete, print, and send an Infectious Disease Serology Test Request (T916) with the specimen.