What does the Chlamydophila pneumoniae IgM test measure?

Why is Chlamydophila pneumoniae IgM measured?

Positive IgM suggests acute or very recent primary infection, though sensitivity is modest and false positives occur. In the setting of prior exposure, reinfection may not trigger detectable IgM, so its absence does not exclude active disease. Interpret IgM alongside IgG and IgA, clinical presentation, and serial titres rather than as a standalone acute-phase marker.

Reference ranges

Standard reference

Negative <0.90; Equivocal 0.90–1.10; Positive >1.10 (index values, assay-dependent).

Functional medicine optimal

Negative index value (<0.90) in the absence of recent respiratory infection.

Units

Index, titre, Index value

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.