- Insulin and glucose are strongly influenced by diet, time of feeding and exercise.
- The interpretations of results from this calculator are only valid for animals fed nothing but hay or pasture from the night before testing through the time of testing, with hay available at all times. If the horse runs out of hay overnight, wait to test until at least 4 hours after hay was provided again.
- No exercise on the day of testing, including vigorous exercise on turnout.
- Some labs report insulin as mU/L which is equivalent to uIU/mL.
- EMS can be diagnosed from insulin alone (RISQI), but it is helpful to know glucose to make sure the horse is not in the diabetic range.
About the Calculator Proxies
The validity of the G:I ratio was established by the AJVR study below which found it was almost equivalent to RISQI. The RISQI and MIRG proxies are a measure of the likelihood that the horse does or does not have normal insulin sensitivity. They are most useful for horses that fall into a grey zone by their insulin level and are within the laboratory reference range (see https://www.ecirhorse.org/FastingInsulin-LabRefRanges.php ).
The proxies were further studied in a field study of a group of ponies. They defined "prelaminitic equine metabolic syndrome" as a profile consisting of body condition score, serum triglyceride levels and RISQI less than 0.32, MIRG greater than 5.6 which predicted which ponies were at risk for pasture associated laminitis. The proxies are not 100% accurate in predicting risk (no test is) but it is important to know that they do not overdiagnose EMS. If anything, they are more likely to miss cases. It should also be noted that the insulin assay used to establish the proxies is no longer being used and that different labs use different assays so results may differ.
- Treiber KH, Kronfeld DS, Hess TM, Boston RC, Harris PA. Use of proxies and reference quintiles obtained from minimal model analysis for determination of insulin sensitivity and pancreatic beta-cell responsiveness in horses AJVR, Vol 66, No. 12, December 2005.
- Treiber KH, Kronfeld DS, Hess TM, Byrd BM, Splan RK, Staniar WB. Evaluation of genetic and metabolic predispositions and nutritional risk factors for pasture-associated laminitis in ponies. J Am Vet Med Assoc. 2006 May 15;228(10):1538-45.