Print E-mail
Volume 47, Number 2, April 2014

Comparison of real-time polymerase chain reaction and serological tests for the confirmation of Mycoplasma pneumoniae infection in children with clinical diagnosis of atypical pneumonia 


Hsin-Yu Chang, Luan-Yin Chang, Pei-Lan Shao, Ping-Ing Lee, Jong-Min Chen, Chin-Yun Lee, Chun-Yi Lu*, Li-Min Huang*


Received: April 30, 2012    Revised: June 30, 2012    Accepted: August 31, 2012   

 

Corresponding author:

Corresponding authors. Department of Pediatrics, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei, Taiwan. 



 

Background and purpose: 

Mycoplasma pneumoniae is a common pathogen of respiratory tract infection in children, and its correct and rapid diagnosis is a clinical challenge. Real-time polymerase chain reaction (RT-PCR) has been used frequently for the detection of this pathogen.
 



 

Methods:

Medical records from all children with a clinical diagnosis of mycoplasma pneumonia and whose respiratory samples were tested for M. pneumoniae (using RT-PCR) during 2011 were reviewed retrospectively. We compared the sensitivity and specificity of serological assays versus those of RT-PCR for diagnosis of M. pneumoniae infections. We also reviewed retrospectively clinical characteristics, and laboratory and imaging findings of children with laboratory evidence of M. pneumoniae infection. 



 

Results:

In 2011, 290 children were diagnosed to have mycoplasma pneumonia clinically and had their respiratory samples tested for M. pneumoniae by RT-PCR. Fifty-four children (19%) had a positive result. Meanwhile, 63% (182/290) of these children also underwent serological tests, out of whom 44 (24%) were found to be positive for immunoglobulin M (IgM). Using PCR as a gold standard, M. pneumoniae IgM assay was found to show a sensitivity of 62.2% and a specificity of 85.5%. Positive and negative predictive values of IgM were 52.3% and 89.9%, respectively. In M. pneumoniae IgM-positive children, a negative PCR result was associated with more coinfection by other pathogens and longer duration of prehospitalization fever. Bacterial loads of M. pneumoniae were not correlated with clinical outcomes. 



 

Conclusion:

The majority of clinically diagnosed mycoplasma pneumonia was unconfirmed. Mycoplasma pneumoniae IgM has poor sensitivity and a positive predictive value. Interpretation of Mycoplasma pneumoniae IgM should be done with caution. 



 

Key words:

Immunoglobulin M, Mycoplasma pneumoniae, Polymerase chain reaction