In human testing for Chlamydia psittaci, MIF testing evaluates which antibody classes?

In human testing for Chlamydia psittaci, MIF testing evaluates which antibody classes?

• A. IgM
• B. IgG
• C. IgA
• D. IgM, IgA, and IgG

Answer: (D)

Micro-immunofluorescence for Chlamydia psittaci is designed to detect the human antibody response across multiple immunoglobulin classes, not just one. In psittacosis, IgM appears early, signaling acute infection; IgG develops and persists, indicating longer-term exposure or ongoing immune response; and IgA can be present in mucosal immunity and can boost detection in some cases. Because the test can measure all three isotypes, it provides a more complete serologic picture than testing for a single class. This is why choosing the option that includes IgM, IgA, and IgG best fits how MIF is used for this organism.

Micro-immunofluorescence for Chlamydia psittaci is designed to detect the human antibody response across multiple immunoglobulin classes, not just one. In psittacosis, IgM appears early, signaling acute infection; IgG develops and persists, indicating longer-term exposure or ongoing immune response; and IgA can be present in mucosal immunity and can boost detection in some cases. Because the test can measure all three isotypes, it provides a more complete serologic picture than testing for a single class. This is why choosing the option that includes IgM, IgA, and IgG best fits how MIF is used for this organism.