SUMMARY
Polymerase chain reaction (PCR) is a key technology of genetic testing, but the long thermal cycling time has been a problem in achieving rapid diagnosis of pathogenic organisms and cancer. We describe a simple, portable, and rapid genetic testing system based on ultrafast segment flow and fluorescent detection. In particular, we improved the flow‐through PCR to accelerate the thermal cycling time and simplify the operation for practical use. The PCR solution was injected in a small volume of about several microliters by an air syringe, and flowed as segment flow. The segment of PCR solution was moved in a serpentine microchannel on a microfluidic device over two temperature zones for denaturation and annealing/extension reactions. The base plate formed upon the serpentine microchannel pattern was made of cyclo‐olefin polymer (COP) and covered with a thin transparent film. Furthermore, a specialized portable system was developed for the microfluidic device of a segment‐flow PCR. Heater units, a syringe pump, a fluorescence detector, and PC were integrated in a suitcase for portable use. Using this portable system, a microorganism modeling anthrax and a point mutation of FGFR3 gene were successfully detected within 6.5 min.