Sed Rate by Modified Westergren (ESR) Test
The Sed Rate by Modified Westergren test, commonly called ESR, measures how quickly red blood cells settle in a tube of whole blood over a set time. Quest describes it as a way to help differentiate inflammatory and neoplastic conditions and as a general index of disease severity.
About this test
ESR is a longstanding, general marker of inflammation. Quest's description ties it to helping identify inflammatory and neoplastic conditions and to gauging disease severity, rather than to any single diagnosis.
Quest lists this test under several names, including Sed Rate by Modified Westergren, WSR, Zeta Rate, Sedimentation Rate and Erythrocyte Sedimentation Rate; all refer to the same measurement.
Test details
| Quest code | 809 |
|---|---|
| Methodology | Modified Westergren |
| Sample type | Whole blood |
| Collection | Quest patient service center |
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Additional details
What this test looks at
The test reports one value: the rate at which red blood cells settle in a tube of whole blood, using the Modified Westergren method. It does not identify what is causing a change in that rate; Quest describes its role as differentiating inflammatory and neoplastic disease and gauging disease severity.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does the ESR test measure?
It measures the rate at which red blood cells settle in a tube of whole blood over a set time, using the Modified Westergren method.
How is the sample collected?
The test uses a whole blood sample, collected in an EDTA (lavender-top) tube, from a routine blood draw.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Can an ESR result tell me what is causing inflammation?
No. ESR is a general marker; Quest describes it as helping differentiate inflammatory and neoplastic conditions and gauging disease severity, but a clinician reads it alongside symptoms, history and other results to identify a cause.
What other names is this test listed under?
Quest lists it under names including Sed Rate by Modified Westergren, WSR, Zeta Rate, Sedimentation Rate and Erythrocyte Sedimentation Rate.
How much is a Sed Rate test?
$25, paid once at checkout. The price includes the physician's order this test requires and sample collection at a Quest patient service center.