Patient Sample Army Spc. David Pyke, a medical laboratory technician, loads a patient sample for rapid COVID-19 polymerase chain reaction, or PCR, testing at Brooke Army Medical Center, Joint Base San Antonio-Fort Sam Houston, Texas, April 9, 2020. PCR is the central technology for COVID-19 testing. SHARE: Download: Full Size (1.28 MB) Tags: Air Force, Coronavirus Credit: Jason W. Edwards, Army VIRIN: 200409-A-HZ730-1030C.JPG Photo Gallery