This is a single-marker test measuring the presence of antibodies against insulin in the blood. It is particularly useful in patients who have not yet been treated with insulin but present with symptoms suggestive of diabetes or have a family history of the condition. This test aids in differentiating between type 1 diabetes mellitus (autoimmune), type 2 diabetes mellitus, and atypical forms like latent autoimmune diabetes in adults (LADA). It is also valuable in assessing the risk of future type 1 diabetes and in diagnosing rare autoimmune hypoglycemic syndromes.