As COVID-19 self-test kits become as integral to our homes as other toiletries, the red lines are no longer as confounding as they once were. But what about the polymerase chain reaction (PCR) tests? What do they show and how do we interpret the results? Prof James Koh Kwee Choy, Consultant Infectious Diseases Specialist and Professor of Medicine in IMU, explains the basics of CT values and what we need to know about PCR tests. Article is in Mandarin. Learn more about this at Kenali Ujian PCR (Harian Metro, 30 March 2022).