Multiplex polymerase chain reaction diagnostic testing for respiratory pathogens in acutely ill children

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Oulu University Hospital, Auditorium 12

Topic of the dissertation

Multiplex polymerase chain reaction diagnostic testing for respiratory pathogens in acutely ill children

Doctoral candidate

Licentiate of medicine Suvi Mattila

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, Research Unit of Clinical Medicine

Subject of study



Professor Per Ashorn, University of Tampere, Tampere University Hospital


Professor Terhi Ruuska, University of Oulu, Oulu University Hospital

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Diagnostic testing for respiratory pathogens in acutely ill children

Most respiratory infections in children are caused by viruses, but clinical presentations with all respiratory infections overlap and it is difficult to distinguish viral from bacterial infections based on the clinical evaluation alone. Due to diagnostic uncertainties, unnecessary antibiotics are often prescribed. Diagnostic methods based on nucleic acid amplification techniques have been revolutionized within the last decades creating platforms that can simultaneously detect various respiratory viruses or bacteria. Due to their workflow simplicity, these devices can be placed in an emergency room so that the test results will be available to the physician in approximately one hour. However, limited data are available on the clinical benefits of multiplex PCR testing for respiratory pathogens in acutely ill children. This doctoral thesis shows that multiplex PCR testing for respiratory pathogens has a limited impact on clinical decision -making. All the data used in this thesis was gathered in the pediatric emergency room of Oulu University Hospital.

In the initial cross-sectional study of 1195 children with respiratory symptoms or fever, at least one bacterial pathogen was detected in 50% of the patients. Mycoplasma pneumoniae was detected in 13 patients (1.1%) and Chlamydia pneumoniae in 2 (0.2%). Detection of atypical bacteria (Mycoplasma pneumoniae or Chlamydia pneumoniae) was associated with antibiotic prescriptions and clinical diagnoses of pneumonia.

In the subsequent cohort study of 800 children, the cycle threshold values, inversely reflecting the pathogen load, were not associated with hospitalization, any need for respiratory support, or any need for intensive care.

In a randomized trial including 1243 children, point-of-care multiplex PCR testing for 21 respiratory pathogens did not reduce the overall use of antibiotics in the emergency department or increase targeted antibiotic prescriptions. The length of stay in the emergency room was 13 minutes longer in the intervention group.
Last updated: 8.5.2024