If an undiagnosed pda was causing a murmur in an adult, would it show up in echo/ doppler?

PDA: A PDA would usually show up in a complete echo doppler exam. As with any test, technical factors could lead to it being missed.

It should!: If the echocardiogram was a complete study, with careful imaging, performed by a sonographer experienced in congenital heart disease and interpreted by a cardiologist competent in interpreting studies on patients with congenital heart disease, then the likelihood of detecting a PDA is high. If experience was low, or the study was incomplete, the diagnosis could be missed.