15 Inflammation Markers Your Doctor Can Test and What Each One Means

3. Erythrocyte Sedimentation Rate (ESR) - The Time-Tested Inflammation Indicator

The Erythrocyte Sedimentation Rate, commonly known as ESR or "sed rate," represents one of the oldest and most enduring inflammatory markers in clinical medicine, having been used for over a century to detect and monitor inflammatory conditions. This test measures how quickly red blood cells settle to the bottom of a specially designed tube over the course of one hour, with faster settling rates indicating higher levels of inflammation-promoting proteins in the blood. During inflammatory states, the liver produces increased amounts of fibrinogen and other acute-phase proteins that cause red blood cells to stick together and form larger clumps, which settle more rapidly due to their increased weight. Normal ESR values vary significantly with age and gender, with typical ranges being 0-15 mm/hr for men under 50, 0-20 mm/hr for men over 50, 0-20 mm/hr for women under 50, and 0-30 mm/hr for women over 50. While ESR is less specific than newer inflammatory markers, it remains valuable for monitoring chronic inflammatory conditions like rheumatoid arthritis, temporal arteritis, and polymyalgia rheumatica, where changes in ESR levels can help assess disease activity and treatment response. The test's main limitations include its non-specific nature and the fact that it can be influenced by factors unrelated to inflammation, such as anemia, pregnancy, kidney disease, and certain medications.