What Is a SED Rate Blood Test?

Submitted on March 27, 2012

The sed rate blood test is sometimes called the esr sed rate blood test or simply the ESR test. Its full form is Erythrocyte Sedimentation Rate, where the 'Sedimentation rate' is abbreviated to 'sed rate'.

What Is a SED Rate Blood Test?

The sed rate blood test is quite common and is used for detecting and monitoring inflammation inside the body. It collects red blood cells (erythrocytes) in a test tube, and then measures the sedimentation rate (sed rate) of this blood over a specific period of time. The greater number of red cells that settle down or fall more quickly to the bottom of the test tube indicates a higher sed rate.

A high sed rate blood test indicates inflammation in the body. This is because during inflammation, some specific proteins make the red blood cells stick to each other and become heavier. This causes them to fall to the bottom of the tube, more quickly than is otherwise normal. These proteins are usually produced by the immune system and the liver, when the body is undergoing abnormal conditions such as an autoimmune disorder, tissue death (necrosis), tuberculosis, some forms of arthritis, certain infections which cause vague inflammations, or cancer.

Age and gender also govern the sedimentation rate. The sedimentation rate for men is around 15 mm per hour, while for women it is around 20 mm per hour. This increases after the age of 50. For men it becomes around 20 mm per hour, and for women it is around 30 mm per hour.


A vein on the inside of the elbow is selected and the site cleaned with an antiseptic. The skin is then punctured and blood drawn into a vial or pipette. The area is then bound with a light bandage. You may feel a slight stinging sensation when the needle pricks you, and you may have a slight bruise or throbbing sensation at the site for a few days. There is generally no other ill effects of the test.

Interpretation of Test Results

High sed rate blood test results may indicate kidney disease, syphilis, anemia, osteomyelitis, thyroid disease, lupus, rheumatic fever or arthritis or multiple myeloma. On the other hand, low sed rates may imply low plasma protein (caused by kidney or liver disease), sickle cell anemia or congestive heart failure. Scleroderma, pelvic inflammatory disease, pericarditis (usually after a heart attack), certain skin lesions or endometritis may also affect the sedimentation rates.

However, sometimes the results may not be conclusive, and you may need other more specific tests to determine your problem.