measurement of fasting insulin concentration involves giving a horse a single flake of hay, low in non-structural carbohydrates, at 10 pm the night before testing. blood being drawn the following morning, usually between 8 and 10am. both insulin and glucose blood levels are measured. hyperinsulinemia suggests insulin resistance. this test is easy to perform, but is less sensitive than the oral sugar test. it is best used in cases where risks of laminitis make the oral sugar test potentially unsafe.