Includes Chlamydophila pneumoniae, Chlamydophila psittaci, and Chlamydia trachomatis.
Antichlamydial IgG can persist for years. All results from chlamydial serologies must correlate with clinical history and other data available to the physician.
Specimens collected too early during primary infection may not contain detectable antibodies. If chlamydial infection is suspected, a second specimen should be collected 10 to 21 days later and tested in parallel with the original specimen.
During a primary Chlamydia infection, the early antibody response may be cross-reactive with multiple Chlamydia species.
The Chlamydia microimmunofluorescent antibody assay utilizes serotypes D-K of Chlamydia trachomatis. Sera from suspected cases of lymphogranuloma venereum (LGV) should be tested by a Lymphogranuloma Venereum Differentiation Antibody Panel. LGV testing is not performed by Mayo Clinic Laboratories; call 800-533-1710 for further assistance.
Due to the limited sensitivity and specificity of Chlamydia serologic tests, patients with suspected C trachomatis infection should be tested by a molecular method (eg, CTRNA / Chlamydia trachomatis by Nucleic Acid Amplification [HOLOGIC], Varies) when clinical manifestations are present.
> or =1:512
IgG endpoint titers of 1:512 or more are considered presumptive evidence of current infection.
<1:512 and > or =1:64
A single specimen endpoint titer of from 1:64 to 1:512 should be considered evidence of infection at an undetermined time. A second specimen drawn 10 to 21 days after the original draw 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.
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.
Chlamydophila pneumoniae antibody is detectable in 25% to 45% of adults tested.
Chlamydophila psittaci and Chlamydia trachomatis
> or =1:64
IgG endpoint titers of 1:64 or more are considered presumptive evidence of current infection.
Chlamydophila pneumoniae, Chlamydophila psittaci, and Chlamydia trachomatis
> or =1:10
IgM endpoint titers of 1:10 or more are considered presumptive evidence of infection.
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.