Exhaled Breath Electronic Nose for Multi-Disease Risk Prescreening (BREATH-PAN)

Development and Validation of an Exhaled Breath Electronic Nose Platform for Multi-Disease Risk Prescreening: A Prospective Multicenter Study

This prospective multicenter observational study will evaluate whether an electronic nose that analyzes patterns in exhaled breath can be developed as a noninvasive tool for early risk prescreening across several disease areas. The study will enroll up to 20,000 adults from hospitals and health examination centers. It will first establish a standardized breath-sampling and quality-control procedure and assess repeatability across breathing maneuvers, devices, centers, and time. It will then develop and independently evaluate risk prescreening models for prespecified disease modules, including lung cancer/clinically significant pulmonary nodules, chronic respiratory diseases, and metabolic/endocrine diseases, with additional exploratory modules involving liver, kidney, cardiovascular, and systemic inflammatory/infectious/immune conditions.

The electronic-nose results are for research only and will not be reported to participants or clinicians or used to change routine screening, diagnosis, or treatment. Disease reference status will be determined from examinations, laboratory tests, imaging, pathology, pulmonary function testing, specialist assessments, or follow-up that are already performed as part of routine care. The study will evaluate screening sensitivity, specificity, false-negative rate, predictive values, calibration, and performance across different centers, devices, and time periods.

Study Overview

• Status: Not yet recruiting
• Conditions: Lung Cancer; Pulmonary Nodule; Metabolic Disease; Chronic Respiratory Disease; Endocrine Disease
• Intervention / Treatment: Diagnostic test: Electronic-Nose Breath Assessment

Detailed Description

This is an investigator-initiated, prospective, multicenter, observational, staged platform cohort study involving hospitals and health examination centers. The study is designed to establish a standardized and traceable exhaled-breath electronic-nose platform and to evaluate its potential role as a first-line risk prescreening tool rather than as a stand-alone diagnostic test. Up to 20,000 participants will be prospectively enrolled.

The first stage is a methodological standardization and cross-center consistency cohort of approximately 500 clinically stable participants. Each participant will complete three predefined breathing maneuvers in randomized order: end-expiratory sampling without breath holding, sampling after a 5-second breath hold, and sampling after a 10-second breath hold. Each maneuver will be repeated twice. At least 250 participants will undergo repeat sampling at 7±3 days and 30±7 days, and selected participants will undergo cross-device or cross-center bridge sampling. Repeatability, within-participant variability, sample validity, tolerability, and device/center consistency will be evaluated to determine the locked sampling and quality-control procedure for the subsequent large cohort.

The second stage is a multi-disease risk prescreening cohort of approximately 19,500 participants. Prespecified major disease modules include lung cancer/clinically significant pulmonary nodules, chronic respiratory diseases, and metabolic/endocrine diseases. Liver, kidney, cardiovascular, and systemic inflammatory/infectious/immune conditions will be evaluated as secondary or exploratory modules. Because participants may have more than one condition, disease outcomes will be modeled using a multi-label rather than mutually exclusive classification framework.

Approximately 12,000 participants will be used for model development, approximately 3,000 for temporally independent evaluation, and approximately 4,500 from prespecified held-out centers for whole-center external evaluation. Preprocessing procedures, model architecture, features, module-specific screening thresholds, and the overall screening rule will be locked before evaluation data are analyzed. Temporal and whole-center external evaluation datasets will not be used for model tuning or threshold selection.

Reference status for each disease module will be determined from routine clinical or health-screening information, including laboratory testing, pulmonary function testing, imaging, pathology, specialist assessment, and routine follow-up as applicable. The study will not require additional CT scans, blood sampling, endoscopy, surgery, or other invasive procedures solely to establish the reference standard. Participants with insufficient reference information will not be included in the corresponding primary accuracy analysis.

Primary evaluation of the locked risk prescreening models will include sensitivity, specificity, false-negative rate, and 95% confidence intervals at fixed thresholds. Positive predictive value, negative predictive value, and screening-positive rate will also be reported in consecutively recruited intended-use populations without case enrichment. Secondary analyses will assess AUROC, AUPRC, likelihood ratios, Brier score, calibration, decision-curve net benefit, subgroup performance, and transportability across centers, devices, and acquisition periods.

A nested longitudinal/repeat-sampling cohort of approximately 600-1,000 participants, with an upper limit of 3,000, may undergo repeat breath sampling at routine preoperative/postoperative, treatment, follow-up, or health examination visits to explore within-person temporal changes in breath profiles. These analyses are exploratory and are not part of the primary risk prescreening conclusions.

• Study Type: Observational
• Enrollment (Estimated): 20000

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults aged ≥18 years will be prospectively recruited from participating hospitals and health examination centers. The study population will include individuals undergoing routine health examinations, opportunistic screening, or planned disease-specific screening or clinical evaluation. Clinically stable volunteers will be enrolled in the methodological standardization cohort, while the multi-disease risk prescreening cohort will include consecutively recruited intended-use populations with available routine reference screening or sufficient clinical information for reference-status determination. Patients with suspected or confirmed disease may also be included for model development or exploratory analyses but will not replace the intended-use population for locked external evaluation.

Description

Inclusion Criteria:

Age ≥18 years. Able to provide informed consent and willing to sign written informed consent. Able to understand and follow standardized breathing instructions and safely complete seated exhaled-breath sampling.

Breath sampling is considered by the study physician not to delay or interfere with necessary routine clinical care or health examination.

Routine reference screening results are available for at least one prespecified disease module, or sufficient clinical information is available to determine the corresponding reference status.

Willing to permit authorized study personnel to review relevant medical records and follow-up information within the scope of ethical approval.

Exclusion Criteria:

Refusal to participate, inability to provide valid informed consent, or inability to reliably comply with study procedures.

Acute respiratory distress, active massive hemoptysis, untreated pneumothorax, significant impairment of consciousness, or any condition for which forced exhalation is considered unsafe by the study physician.

Requirement for strict airborne isolation when the study site or equipment cannot meet applicable infection-control requirements.

Recent major surgery, invasive procedure, or other clinical intervention for which the treating physician considers breath sampling should be postponed.

Vomiting, severe nausea, intense coughing, or other conditions before sampling that substantially increase the risk of aspiration, syncope, or related adverse events.

Acute oral or nasopharyngeal conditions, or recent food intake, smoking, alcohol consumption, vigorous exercise, or other factors that prevent standardized breath sampling; such participants may be rescheduled rather than permanently excluded.

Key reference-standard information is unavailable and is not expected to be obtained through routine follow-up.

Any other condition considered by the investigator to make participation inappropriate.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Methodological Standardization Cohort; Approximately 500 clinically stable participants will undergo standardized exhaled-breath sampling to evaluate methodological repeatability and cross-center/device consistency. Participants will complete three predefined breathing maneuvers in randomized order, with each maneuver repeated twice. At least 250 participants will undergo repeat sampling at 7±3 days and 30±7 days, and selected participants may undergo cross-device or cross-center bridge sampling.	Diagnostic test: Electronic-Nose Breath Assessment; Participants will provide standardized exhaled-breath samples for electronic-nose analysis. The electronic-nose system records multichannel gas-sensor responses together with flow, temperature, humidity, and process information. In the methodological standardization cohort, participants will undergo repeated sampling using three predefined breathing maneuvers to assess repeatability and cross-center/device consistency. In the multi-disease risk prescreening cohort, participants will undergo the locked standardized sampling procedure for development and independent evaluation of disease risk prescreening models. Electronic-nose results are for research purposes only and will not be reported to participants or clinicians or used to alter routine screening, diagnosis, or treatment.
Multi-Disease Risk Prescreening Cohort; Approximately 19,500 participants will undergo standardized exhaled-breath electronic-nose assessment before the corresponding routine reference screening results are available. The cohort will be used to develop and independently evaluate multi-label risk prescreening models for prespecified disease modules, including lung cancer/clinically significant pulmonary nodules, chronic respiratory diseases, and metabolic/endocrine diseases, with additional secondary or exploratory disease modules.	Diagnostic test: Electronic-Nose Breath Assessment; Participants will provide standardized exhaled-breath samples for electronic-nose analysis. The electronic-nose system records multichannel gas-sensor responses together with flow, temperature, humidity, and process information. In the methodological standardization cohort, participants will undergo repeated sampling using three predefined breathing maneuvers to assess repeatability and cross-center/device consistency. In the multi-disease risk prescreening cohort, participants will undergo the locked standardized sampling procedure for development and independent evaluation of disease risk prescreening models. Electronic-nose results are for research purposes only and will not be reported to participants or clinicians or used to alter routine screening, diagnosis, or treatment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Same-Day Repeatability of the Locked Exhaled-Breath Sampling Method	Same-day repeatability of electronic-nose measurements obtained using the locked exhaled-breath sampling method will be assessed using the intraclass correlation coefficient (ICC) with 95% confidence intervals based on repeated measurements collected from the same participant during the same visit.	During the baseline sampling visit; repeated samples are collected approximately 3-5 minutes apart.
Screening Performance of the Locked Multi-Disease Risk Prescreening Models	For each prespecified major disease module meeting the required event-number threshold, sensitivity, specificity, false-negative rate, and corresponding 95% confidence intervals will be estimated at the locked screening threshold. Positive predictive value, negative predictive value, and screening-positive rate will additionally be reported in consecutively recruited, non-enriched intended-use populations. Temporal and whole-center external evaluations will be reported separately.	From index breath sampling to completion and adjudication of the corresponding routine reference screening or clinical assessment, up to 16 months after index breath sampling.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Area Under the Receiver Operating Characteristic Curve of the Locked Risk Prescreening Models	For each prespecified major disease module meeting the required event-number threshold, discrimination of the locked risk prescreening model will be assessed using the area under the receiver operating characteristic curve (AUROC) with 95% confidence intervals. Temporal and whole-center external evaluations will be reported separately.	From index breath sampling to completion and adjudication of the corresponding routine reference screening or clinical assessment, up to 16 months after index breath sampling.
Downstream Examination Burden of the Any-Major-Module-Positive Rule	The downstream examination burden of the prespecified "any major module positive" rule will be estimated as the number of participants per 1,000 individuals screened who would be referred for further disease-specific screening or clinical assessment under the locked rule.	From index breath sampling to completion and adjudication of the corresponding routine reference screening or clinical assessment, up to 16 months after index breath sampling.
Valid-Sample Rate of Standardized Exhaled-Breath Sampling	The valid-sample rate will be defined as the proportion of completed exhaled-breath sampling procedures that meet the prespecified locked quality-control criteria for a valid electronic-nose sample.	During each exhaled-breath sampling visit.
Short-Term Stability of the Locked Exhaled-Breath Sampling Method	Short-term stability of electronic-nose measurements obtained using the locked sampling method will be assessed using the intraclass correlation coefficient (ICC) with 95% confidence intervals across baseline and repeat measurements at 7±3 days and 30±7 days.	From baseline sampling through the 30±7-day repeat-sampling visit.
Adverse Event Rate During or Immediately After Exhaled-Breath Sampling	The adverse event rate will be defined as the proportion of participants experiencing one or more adverse events during or immediately after exhaled-breath sampling, including cough, dyspnea, chest tightness, dizziness, nausea, syncope, hypoxemia, or other adverse events recorded in association with the sampling procedure.	During and immediately after each exhaled-breath sampling procedure.

Collaborators and Investigators

• Sponsor: The First Affiliated Hospital of Guangzhou Medical University

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: August 15, 2026
• First Submitted That Met QC Criteria: August 31, 2026
• First Posted (Actual): September 4, 2026

Study Record Updates

• Last Update Posted (Actual): September 4, 2026
• Last Update Submitted That Met QC Criteria: August 31, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Artificial Intelligence; Machine Learning; Exhaled Breath; Electronic Nose; Multi-Disease Risk Prescreening; Noninvasive Screening
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Respiratory Tract Diseases; Lung Diseases; Respiratory Tract Neoplasms; Thoracic Neoplasms; Nutritional and Metabolic Diseases; Lung Neoplasms; Metabolic Diseases; Endocrine System Diseases
• Other Study ID Numbers: BREATH-PAN-01

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No