Re: ACTH, iron overload and WNV titer results for IR mare

Lavinia Fiscaletti

Hi Cass,

Cornell's upper limit is 35pg/ml so 26.5 is solidly within normal range. If I had that result with Dante I'd be ecstatic. In and of itself it doesn't warrant pergolide. However, as this is a solid elevation from 2 years ago, I'd consider running blood work again in late Aug/early Sept to see what is happening when the actual seasonal rise period kicks in. Are the elevated leptin and slightly runny eye new? Maybe Cayuse will be a candidate for pergolide only during the seasonal rise period. Wish this was a" black and white" type issue but it seems to fall in one of those hmmm... grey areas.

Here is a post form Dr. Kellon addressing the iron panel results:

The tests in an iron screen are:

1. Serum iron - the amount of iron circulating in the blood. This
primarily reflects the amount the horse is absorbing from his diet.
Upper normal is between 150 and 190 for most labs.

2. TIBC - Total iron binding capacity. This is a measure of
transferrin, a protein in the blood that binds and carries iron.
Free iron is very damaging to the tissues. TIBC normally increases
as serum iron increases. Like serum iron, it can't be used as a
measure of body iron load. KSU has reported seeing them as high as
455, but I have several higher than that, in both the normal and the
IR group. Think of it as a "reaction" to the presence of iron in the
blood, like insulin going up is a "reaction" to blood glucose.

3. TSI - Transferrin saturation index. This is a calculation, iron
divided by TIBC x 100, that shows how much of the transferrin
protein is saturated with iron. TSI does correlate with body iron
burden, and also with how much iron is being absorbed. Upper normal
is somewhere in the low 40s.

4. Ferritin - This is the protein that binds iron in the tissues and
has been proven in horses to correlate very well with body iron
burden. It can also be elevated with inflammation, malignancy,
severe trauma, etc. but in that case the serum iron and TIBC go down.
Horses in the IR study that were actively laminitic and showed the
pattern of high ferritin but low iron and TIBC were not included so
that there would be no false elevation of ferritin values. Serum
ferritin of normal horses in Dr. Smith's study showed a mean of 152
with a standard deviation of 54.6, which means 152 was the average
and most (95%) of the horses fell within a range of 97.4 to 206.6.
My normals were similar, 139 plus or minus 43.9.

More info in the file on iron here:

Check the folder Iron: Dr. Kellon on Iron Overload.doc

Can't help with the vaccination/titre part of your question but as this has come up before, here is one previous message:

Lavinia, Dante, Georeg Too and Peanut
Jan 05, RI
EC Support Team

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