Evaluation of Rapid Colorimetric Lateral Flow Sensor for Hypoxia-Inducible Factor-1 Alpha Detection in High Altitude

Abstract

Hypoxia is a critical physiological risk in high-altitude aviation and aerospace environments, where early detection is essential to prevent cognitive impairment and loss of consciousness among aircrew. Hypoxia-inducible factor-1 alpha (HIF-1α) is a molecular biomarker that is rapidly upregulated under low-oxygen conditions. This study aimed to develop and evaluate a rapid, non-invasive lateral flow immunoassay (LFIA) for colorimetric detection of salivary HIF-1α. A total of 24 saliva samples were collected from participants at the Institute of Aviation Medicine and divided into two groups: sea level (control) and simulated altitude exposure at 10,000 feet. Salivary HIF-1α was detected using the developed LFIA sensor, while peripheral oxygen saturation (SpO₂) was concurrently measured using fingertip pulse oximetry to confirm hypoxic status. All participants tested negative for HIF-1α at sea level, whereas positive LFIA results were observed in all participants after altitude exposure, indicating 100% sensitivity under the study conditions. Mean SpO₂ decreased significantly from 98.1% at sea level to 90.8% at 10,000 feet. The LFIA produced rapid, visually interpretable results within minutes. The LFIA demonstrated high sensitivity and specificity for detecting hypoxia-induced HIF-1α in saliva, potentially as a rapid point-of-care tool for hypoxia monitoring in aviation and extreme environments.