Right - I have info from a researcher stating that
improvement with treatment was an adequate form of diagnosis. A tap is several
hundred $$ and IMO fairly risky, for information that may or may not actually
assist diagnosis/treatment.
You can get Marquis from the catalogs for about
$650-700 now.
Kristen in TX [whose gelding as it turned out needed
arthroscopic stifle surgery, not Marquis, but we didn't know this until after I
had done all the research on EPM]
If you treat it with meds and nothing
changes, you may be out the money but the spinal might not have told you all
that much more. It will however, be very painful for your horse.