Yes, 10 is about right although 12 or 13 might be a more realistic upper estimate. **Important** This is for a fed horse with a diet that doesn't contain anything with ESC + starch greater than a mixed pasture. With those conditions, a normal horse will not test positive. Although this may seem like a rather strict set of criteria the reality is that it misses some IR horses.
It has been estimated it takes an insulin of 80+ to precipitate an acute laminitis picture **but** IR horses have ongoing occult damage to their laminae even if not classically laminitic.
The whole purpose here isn't to hang a diagnosis on the horse (or not) but to get some insight into their metabolism so that you can feed and manage them accordingly and prevent problems. -- Eleanor in PA
