Erythrocyte Sedimentation Rate (ESR, Sed Rate, Sedimentation Rate) is a laboratory blood test that indirectly measures the degree of inflammation in the body. It measures the rate of settling or sedimentation of red blood cells (erythrocytes) in a tall, thin tube of blood collected from a patient.
Proteins produced during inflammation cause erythrocytes to move close together and stack up in a group. When red blood cells are in group, they become heavier (denser) so they settle faster. The further erythrocytes settle and the faster they fall, the higher is the value of ESR. ESR blood test result is reported as how many millimeters of plasma (clear, yellowish fluid component of the blood) are present at the top of the thin tube in one hour.
Uses of Erythrocyte Sedimentation Rate (ESR)
ESR blood test helps in the diagnosis of conditions associated with acute and chronic inflammation such as infections, cancers, and autoimmune diseases. Although ESR blood test can tell that there is inflammation in the body, it cannot tell what condition or disease is causing the inflammation. Doctors use ESR blood test result in conjunction with other clinical findings, laboratory test results, and the patient’s health history in diagnosing the disease of a patient.
There are many conditions that may cause inflammation and increase ESR: rheumatoid arthritis, lupus, anemia, endocarditis, kidney diseases, osteomyelitis, tuberculosis, syphilis, thyroid disease, rheumatic fever, systemic body infection, giant cell arteritis, pregnancy, multiple myeloma, polymyalgia, vasculitis, and other inflammatory diseases.
There are also conditions that result in lower-than-normal ESR: sickle cell anemia, polycythemia, blood hyperviscosity, low plasma protein due to certain diseases, decreased blood fibrinogen levels (hypofibrinogenemia), and congestive health failure.
Normal Erythrocyte Sedimentation Rate (ESR)
There are two laboratory methods in measuring erythrocyte sedimentation rate: the Westergren and Wintrobe method. The Westergren method is used in most laboratories worldwide. Below are the normal ESR results using Westergren method (in millimeters per hour (mm/hr) :
-Less than 15 mm/hr for men under 50 yrs old
-Less than 20 mm/hr for women under 50 years old
-Less than 20 mm/hr for men over 50 yrs old
-Less than 30 mm/hr for women over 50 years old
- 0-2 mm/hr for newborns
- 3-12 mm/hr for children in neonatal and puberty stage