Re: Diagnostic testing for EMS, EC, and hypothyroidism
Hi, Kirsten - I am sorry that I somehow missed your first post, because I am just down the road from you in Smithers. Since our courier (can't remember if it was DHL or Purolator) didn't get on the Banker's Dispatch contract, we have no more aircraft courier service from here, and I assume Kitimat/Terrace is in the same boat. This makes it really tough to get blood to the lab in a timely manner. It cost me $300 for the last shipment to Guelph, and took 48 hours to get there (that was the most time-effective). I see, however, that if you can keep the weight and package size down, you should be able to do it for about $120 (I obviously had too much ice in the box!)
You have already gotten some great information from Paula, Eleanor, and Dawn - I can add a little perspective from BC.
As horse owners, we really do have to be advocates for our horses. Veterinarians are constantly exhorted to use *only* "best practices", and what that means for EMS horses is the stuff put out by the Equine Equinology Group. Yes, the oral sugar test will pick up more borderline cases, and have fewer false negatives, but the risk of precipitating a laminitic event is very real. Besides, if you have a cresty horse with sore feet and fat pads, and you get a high baseline insulin, you don't need to do the oral sugar test. If it looks like a duck, walks like a duck, and quacks like a duck, it is probably not a loon.
Regarding which tests to use: Leptin is useful in that it can help distinguish high insulin due to IR, vs high insulin driven by PPID and high ACTH. It does add to the cost, because Guelph has to send that out to Cornell, while the other tests are done in-house. If funds are an issue (and when are they not?) then you can skip the leptin test. At age 20, the ACTH is very definitely indicated.
Regarding when to test the ACTH for PPID, yes, you should test soon (as long as there is no overt severe pain present); If the ACTH is above normal, then start pergolide (see Pergolide 101 here: https://ecir.groups.io/g/main/files/3%20Cushings%20Disease%20-%20PPID/Cushings%20Disease%20Treatments/Pergolide ) and then re-test ACTH in late August/September to make sure you have enough pergolide on board for the seasonal rise.
If the ACTH is normal, then still re-test in August or September, because many early PPID horses have normal ACTH in the "low season" (February through June), but will spike an abnormal ACTH during the seasonal rise (August through November). Here is a graph of ACTH values for the UK: https://ecir.groups.io/g/main/files/Blood%20Testing%20for%20IR%20and%20PPID/Blood%20Testing%20for%20Cushings%20-%20PPID/Seasonal%20Influences%20on%20ACTH/Liphook%20study:%20Pituitary%20Pars%20Intermedia%20Dysfunction.pdf
Cheers, and welcome to another BC person!
Jaini Clougher (BSc, BVSc)
Merlin (over the bridge), Maggie, Gypsy, Ranger
ECIR mod/support, BC 09
DDT+E = effective treatment for PPID and EMS/IR equines: https://bit.ly/2J4ZgYT