ESR

Specimen Required

3cc EDTA BLOOD (CBC VIAL)

Fasting Required

Purpose of the Test

To detect and monitor the activity of inflammation as an aid in the diagnosis of the underlying cause

When this test is required

A doctor usually requests an ESR test (along with others – see below ‘What other tests might my doctor be requesting besides ESR?’) to evaluate a patient who has symptoms that suggest polymyalgia rheumatica or temporal arteritis, such as headaches, neck or shoulder pain, pelvic pain, anaemia, unexplained weight loss, and joint stiffness. There are many other conditions that can result in a temporary or sustained elevation in the ESR and some that will cause a decrease.Since the ESR is a non-specific marker of inflammation and is affected by other factors, the results must be used along with the doctor’s other clinical findings, the patient’s health history, and results from other appropriate laboratory tests. If the ESR and clinical findings match, the doctor may be able to confirm or rule out a suspected diagnosis. A single elevated ESR, without any symptoms of a specific disease, will usually not give the doctor enough information to make a medical decision.Before doing an extensive investigation looking for disease, a doctor may want to repeat the ESR test after a period of several weeks or months. If a doctor already knows the patient has a disease like temporal arteritis (where changes in the ESR mirror those in the disease process), they may use the ESR at regular intervals to assist in monitoring the course of the disease. In the case of Hodgkin’s disease, for example, a sustained elevation in ESR may be a predictor of an early relapse following chemotherapy.

What the Test Detects

ESR is an indirect measure of the degree of inflammation present in the body. It actually measures the rate of fall (sedimentation) of erythrocytes (red blood cells) in a tall, thin tube of blood. Results are reported as how many millimetres of clear plasma are present at the top of the column after one hour. Normally, red cells fall slowly, leaving little clear plasma. Increased blood levels of certain proteins (such as fibrinogen or immunoglobulins, which are increased in inflammation) cause the red blood cells to fall more rapidly, increasing the ESR.See MoreSee Less

Preparation for the Test

None

Sample Requirements

A blood sample taken from a vein in the arm

Additional Notes

The ESR and C-reactive protein (CRP) are both markers of inflammation. Generally, ESR does not change as rapidly as the concentration of CRP, either at the start of inflammation or as it goes away. CRP is not affected by as many other factors as is ESR, making it a better marker of some types of inflammation. However, because ESR is an easily performed test and CRP must be done using sophisticated laboratory equipment, many doctors still use ESR as an initial test when they think a patient has inflammation.Females tend to have a slightly higher ESR, and menstruation and pregnancy can cause temporary elevations.Drugs such as dextran, methyldopa (Aldomet), oral contraceptives, penicillamine procainamide, theophylline, and vitamin A can increase ESR, while aspirin, steroids, and quinine may decrease it.

Selected Tests

ESR