We having problem with a  Bayer RA 1000 that we have in a lab in Mexico. It is giving us a reagent tray error and it looks as the wheel can't find home  and continues turning. We have replaced the following components with no results (a) sensor, (b) reagent tray assembly, (c) PCB ...

who can tell me the name of those chemicals ( markers ??? ) used in medical
laboratories do find out the level of catecholamines (epinephrine,
norepinephrine, dopamine etc.)  in 24-hours-urine  ???
Thanks.