High-throughput microscopy (HTM) was developed recently for the automatic detection of airborne asbestos fibers that can cause lung cancer, asbestosis and mesothelioma. The HTM method has been applied to couting the airborne asbestos fibers as an alternative to the conventional phase contrast microscopy (PCM). In this paper, we demonstrated that the HTM enabled us to obtain quantitative results for low-concentration airborne asbestos samples under detection limit, and we made a comparison between the results from HTM and PCM. In addition, a verification study was conducted using proficiency analytical testing (PAT) samples of chrysotile and amosite. The HTM method can be applied to the existing PCM method by reducing analysis time and labors. Potential applications can be extended to detection of asbestos fibers in soil and water. Keywords : Asbestos fiber, Phase contrast microscopy (PCM), High-throughput microscopy (HTM), Automated counting, Image processing