Which lab findings suggest Mycoplasma infections (Mycoplasma pneumoniae)?

Updated: Feb 15, 2019
  • Author: Ken B Waites, MD; Chief Editor: Michael Stuart Bronze, MD  more...
  • Print
Answer

Twenty-five percent of patients develop leukocytosis; the rest have leukocyte counts within the reference range.

Patients may have an elevated ESR.

Cellular response of sputum is mononuclear, with no bacteria visible with Gram staining.

About 75% of patients have a cold agglutinin titer of at least 1:32 by the second week of illness, disappearing by 6-8 weeks. This is not a specific test for M pneumoniae infection but the greater the cold agglutinin titer is (>1:64) in a patient with community-acquired pneumonia, the more likely the cold agglutinins are due to M pneumoniae. No specific abnormalities of hepatic or renal function are likely to occur. [13, 14, 12]

To confirm mycoplasmal respiratory tract infection, culture, molecular-based tests, and/or serological tests are necessary.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!