If you have IgG and IgM antibodies against insulin, your body reacts as if the insulin is foreign. This may make insulin less effective, or not effective at all.
The antibodies can also change the amount of time it takes insulin to work, putting you at risk for low blood sugar. This means that the insulin cannot move glucose from the bloodstream into the cells. As a result, increased levels of insulin are needed to have the same effect, which is called insulin resistance.
If the test shows high levels of IgE antibody against insulin, your body has developed an allergic response to the medication. This could put you at risk for skin reactions, or more severe reactions. Other medications, such as antihistamines or low-dose injectable steroids, may help to lessen the reaction. If reactions have been severe, an in-hospital procedure called desensitization may be necessary.