it has been shown that IGF-1 levels can be normal in some acromegalic cats and can be increased in some cats that do not have acromegaly. Typically we combine a lot of factors in addition to the IGF-1 level when trying to determine whether the index of suspicion is high enough to pursue advanced imaging of the pituitary gland. Interpretation of serum IGF-I test results should always take into consideration the status of control of the diabetic state, the presence and severity of insulin resistance, and the index of suspicion for acromegaly based on review of the history, physical examination, serial blood glucose concentrations, routine blood and urine tests, thoracic radiography, and abdominal ultrasonography. The finding of increased serum IGF-I concentration in a poorly controlled diabetic cat with insulin resistance and clinical features suggestive of acromegaly supports the diagnosis and provides justification for CT or magnetic resonance imaging of the pituitary gland.
... Most of the cats that we have seen tend to have an IGF-1 level at is pretty elevated. In one study they found the average IGF-1 level in the acromegalic cats was 148 nm, however there was a large range.
Some questions about this cat would be what has it's weight been doing - stable, increase, or decrease. A continued increase in weight despite poor diabetic control may be more suggestive of acromegaly. Ultimately, it is possible this could also be the early stages and considering repeating an IGF-1 level in 3 months could be beneficial.
