A major bottleneck has been a shortage of nucleic acid testing kits used to confirm the presence of the coronavirus. So Dr. Zhang proposed that doctors could first use CT scans to detect pneumonia and quickly isolate and treat patients who have it.

CT scans are convenient and can produce immediate results, Dr. Zhang said. Experts say people infected with the coronavirus would be likely to have lesions in both lungs.

Two days after Dr. Zhang posted her proposal online, the Chinese government issued the fifth and latest edition of its national diagnosis and treatment plan. It included a significant change: Doctors in Hubei Province should use CT scans to make a clinical diagnosis of suspected coronavirus infections. The testing kits would then be used to confirm the coronavirus infection.