The validation of device is conducted to 43 confirmed COVID-19 patients and 40 confirmed COVID-19 negative patients from Bhayangkara Hospital, RSLKC Bambalipuro in Yogyakarta Special Region, Indonesia.~Afterwards, patients with symptoms suggesting COVID-19 will be recruited using multicentre consecutive sampling. The minimum number of participants required is 1460 subjects. The study use a triple-blind design where the research subjects, breath sample takers, and sample examiners did not know the results of each sampling that had been done. The final data processor was also blinded to the results of nose and throat swabs. The breath sampling data is saved in graphic form which interpretation will be carried out later by the data processor at the final stage.~This study population involve children and adults who come to the COVID-19 outpatient clinic in each participating hospital with a diagnosis of suspected COVID-19 infection. All patients remain in the setting under medical service in accordance with the standard operating procedure (SOP) and clinical practice guidelines (CPG) protocols for handling patients with suspected COVID-19. The patients underwent nasal and oropharyngeal swabs according to the COVID-19 outpatient CPG.~The participants will be asked about symptoms that they have, such as fever, fatigue, dry cough, stuffy/ runny nose, sore throat, myalgia, shortness of breath, and diarrhea. Afterwards, they will be asked to breathe normally using a mask for 2 times, then inhale and exhale in a forced expiratory volume to an air collecting bag that later is connected to the e-nose machine via a HEPA-filter. The performance of breath test will be compared with the performance of symptoms with the reference of RT-PCR results. In addition, participants' demographic and clinical data will be collected.
Electronic-nose had been used to diagnose other infectious lung diseases, such as tuberculosis. Universitas Gadjah Mada has developed an electronic-nose device which is easy-to-use, portable, and can be manufactured at a low price. Here the investigators test the electronic-nose to diagnose COVID-19 in Indonesia.