The ADIPONECTIN, SERUM A0039 (OS) test measures the level of the adiponectin hormone in your blood to assess metabolic health and risk for conditions like type 2 diabetes, cardiovascular disease, and obesity. The “(OS)” likely refers to the Outpatient Serum collection method, and the A0039 is a lab-specific code for this test. This test evaluates a protein produced by fat cells that helps regulate glucose and fatty acid breakdown, with lower levels linked to increased health risks