For sponsor reasons

This observational study evaluates whether lung sound analysis with LungPass device can be used to differentiate upper and lower respiratory tract infections (URTI and LRTI)

This is a prospective observational study comprised patients presenting with acute respiratory tract infection symptoms in primary care settings. Patients will undergo routine clinical examination including lung auscultation with conventional stethoscope and LungPass device. Moreover, symptoms and anamnesis data, result of diagnostic questionnaire from the LungPass App, complete blood count, C-reactive protein, procalcitonin (PCT) level, SARS-CoV-2 PCR test and X-ray chest examination or CT chest (in case of preliminary clinical suspicion of LRTI). Patients will be followed up within 5-7 days and at the end of the disease in person or by phone for clinical course of the disease assessment to confirm the final diagnosis (URTI or LRTI). Final diagnosis will be considered as Gold standard for accuracy assessment.

Inclusion Criteria:

• Adults (over 18 years) and children (3-18 years) of both sexes;
• Patients able and willing to sign an informed consent to participate in the study (parents of children younger than 18 years old will be allowed to give an informed consent on behalf of their children).
• Patients presenting with a new onset of at least two of listed acute respiratory tract infection symptoms within the last 5 days: cough, purulent sputum, breathlessness, core temperature above 38°C.
• Patients who first visit a GP with these symptoms within the first 5 days from the onset of symptoms and was not previously treated with antibiotics during the last month.

Exclusion Criteria:

• Age up to 3 years;
• Patient refusal to participate in the study (or patients' parents);
• Children under full State care (orphans, children left without parental care);
• Treatment with antibiotics during the last month;
• Patients with subcutaneous emphysema, with damaged skin on the surface of the chest, with drainage in the pleural space, patients undergoing mechanical ventilation;
• Presence of other known chronic lung conditions such as asthma, COPD, tuberculosis, cystic fibrosis or bronchiectasis;
• Mental illness, other known acute diseases or known chronic decompensated diseases, such as a known active malignancy or severe heart failure.
• Other known ongoing infection.

Participants will be recruited in primary care settings upon presentation with symptoms of acute respiratory infection.

It is planned to start recruiting 100 adult patients and 100 children with URTI and 100 adults and 100 children with LRTI. The final calculation of the sample size will be carried out after receiving the preliminary results of the study. After that, the sample size will be adjusted.