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Test Code CHLG Chlamydia IgG, 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


Specimen Required

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.3 mL

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


Secondary ID

619389

Useful For

Assessing IgG antibody levels to aid in the clinical diagnosis of Chlamydia pneumoniae or Chlamydia psittaci infections

Testing Algorithm

This test includes testing for Chlamydia pneumoniae IgG and Chlamydia psittaci IgG.

Method Name

Micro-Immunofluorescent Antibody (MIF) Assay

Specimen Type

Serum

Specimen Minimum Volume

0.15 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

Reference Values

Chlamydia pneumoniae

<1:64

 

Chlamydia psittaci

<1:64

Interpretation

Chlamydia 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.

 

Chlamydia 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. 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

Report Available

Same day/1 to 4 days

Specimen Retention Time

14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86631 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CHLG Chlamydia IgG, IFA, S 10848-0

 

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