Abstract: The disclosure describes how to use an optical-based lateral flow matrix method to accurately monitor and quantify human chorionic gonadotropin (hCG) concentration, 0-150,000 mIU/ml, in specimen from a female. The method relies on using a capture zone immobilized with anti-hCG probes having the capability to capture a maximum of 150,000 mIU/ml of hCG in specimen. The method employs an optical beam to illuminate the entire said capture zone, and precisely quantify said hCG concentration in said specimen by measuring the change of the optical property occurred at said capture zone. The method further includes a mechanism to provide an alarm to inform users according to the test results. According to the invention, the device provides the method for easily and accurately monitoring the daily progress of the pregnancy.