The ESR 1 & 2 Hour test is a simple blood test that helps detect inflammation in your body. It measures how quickly your red blood cells settle at the bottom of a tube over one hour and again after two hours. When inflammation is present—from infections, autoimmune conditions, or chronic diseases—the settling rate becomes faster. By checking both the 1-hour and 2-hour values, your doctor gets a clearer picture of how active or severe the inflammation may be. Though ESR does not diagnose a specific condition on its own, it provides critical, supportive information that helps guide further testing, monitoring, and treatment decisions.