Medical expert of the article
New publications
Antibodies to Mycoplasma pneumoniae in blood
Last reviewed: 05.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Serological diagnostics is based on the detection of the titer of antibodies to Mycoplasma pneumoniae in serum. The most widely used method is the ELISA.
By using ELISA, it is possible to determine antibodies of the IgA, IgM and IgG classes. This method is more sensitive and specific (92% and 95%, respectively) than others. IgM and IgG antibody titers should be determined in the acute period of the disease and after 2-4 weeks. IgM antibodies appear during the first week of the disease and disappear after recovery, but in some cases they can remain in the blood for up to 1 year. The IgG antibody titer begins to increase somewhat later than IgM, but remains elevated longer. An IgM titer higher than 1:10 or a 4-fold increase in the levels of IgA and/or IgG AT in paired sera indicate a current infection. Considering the fact that IgM AT disappear from the blood relatively quickly, in some cases their detection in a single serum sample is sufficient to diagnose an acute infection. The IgA AT titer in elderly patients increases more significantly than IgM antibodies, which must be taken into account when diagnosing the infection. During recovery, IgM antibodies may not be detected in the blood serum, and the content of IgA and IgG AT decreases significantly. Reinfection is accompanied by a rapid increase in the titer of IgA and/or IgG AT. The time for a 4-fold increase in the titer of antimycoplasma antibodies in a sequential study of blood samples taken in the acute period of the disease and during the convalescence period is 3-8 weeks.
Specific IgM antibodies to Mycoplasma pneumoniae are detected in 80% of patients on the 9th day after the onset of the first symptoms of the disease.
On the 7-8th day, IgM antibodies are detected in 88% of patients under 20 years of age and in 40% of older patients. In patients with mycoplasma infection over 60 years of age, there may be no increase in the IgM antibody titer.
Simultaneous determination of IgM and IgG antibodies allows to identify up to 99% of all mycoplasma infections (primary and reinfections), and the study of only IgM antibodies - 78% of primary diseases.
Determination of antibodies to Mycoplasma pneumoniaeused to diagnose mycoplasma infection in chronic inflammatory lung diseases and secondary immunodeficiency states.
[