Equine Medical & Surgical Associates, Inc

Glucose-Insulin Ratios
Why Not The Best Test

Glucose-Insulin ratios are of little value because Insulin Resistance Horses have normal Glucose ranges. High Glucose is very rare and low Glucose from improper testing procedures throw off this ratio. Do not count on this too heavily as a diagnostic tool.
Dr Divers, Cornell University, 2008 J. of Equine Veterinary Science. "Because most horses with EMS maintain glucose within the normal range when fed only low NSC forage, the change in Insulin is the primary determinant of any ration change".

Here is an example of why it is not helpful.
Glucose levels are considered normal between 80 and 120.

Horse A- glucose of 80, insulin of 40 has a 2:1 ratio.
Horse B- glucose of 120 and an insulin of 30 has a 4:1 ratio.

Both horses are normal but ratios are double on Horse B.

Conclusion:

Ratios are not going to find a problem. You know if the Insulin is over 60 there is a problem of Insulin Resistance and you know if the glucose is 40 the sample was handled poorly. Also you will know that if the glucose is sky high, your horse is Early Stage Type II Diabetic and quickly needs help. It is straight forward to diagnose and monitor progress.

Insulin Test Result Chart:

uIU/ml	pmol/L
5-40	<287	Fasting Normal
40-60	287-430	Peak Insulin 2 Hr after breakfast in a normal horse.
80	574	Abnormal- Insulin Resistance Confirmed If blood was taken without a grain challenge and you are in this range you are severely insulin resistant.
120	861
180	1,291
250	1,794
400	2,870
600	4,305

To convert from uIU/ml to pmol/L, multiply by 7.175.
To convert from pmol/L to uIU/ml, divide by 7.175.
If your lab says you are greater then 200uIU/ml, ask them to titrate it out to a real number. This does not cost any extra. If your horse is at 550, and it drops to 210 with management, that is great progress, and you will miss it.
Cornell and Antech use uIU/ml.
Michigan State and Idexx use pmol/L.

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