7 days at +4°C to +8°C
3 days
7 days at +4°C to +8°C
Enzyme-immunoassay
NTU
Interpretation of IgG and IgM (Novatec Units = NTU):
Negative result: < 5 NTU
Doubtful result: 5 - 15 NTU
Positive result: > 15 NTU
C. pneumoniae serology is difficult to interpret due to its lack of specificity, the high prevalence of IgG antibodies in the population (50% in adults) and the slow kinetics of antibodies (REMIC 2018).
The interpretation of serology must therefore take into account both the kinetics of antibodies and the time course of symptoms (N. Miyashita et al 2015): - in primary infection, IgM appear 2 to 3 weeks and IgG appear 6 to 8 weeks after infection - in the event of reinfection, IgM are absent or limited and IgG appear within 1 to 2 weeks following infection
The diagnosis of acute infection should be made in the presence of seroconversion of IgG in two sera collected 2 months apart (B. de Barbeyrac et al 2014).
*** Caution reference values change on 04/10/2025