1838932 LF-RPA lateral flow strip-based recombinase polymerase amplification 8 1838935 LF-RPA lateral flow dipsticks 4 1838933 LF-RPA lateral flow strip 3 1838936 LF-RPA lateral flow recombinase polymerase amplification 2 1838937 LF-RPA amplification-lateral flow 1 1838934 LF-RPA lateral flow RPA 1