ESR Test
This page explains the esr test, what it measures, and how to arrange it. An ESR (erythrocyte sedimentation rate) test measures how quickly red blood cells settle to the bottom of a tall, thin tube of blood. It is a general marker of inflammation in the body, so it is often ordered when a clinician suspects infection, an autoimmune condition, or another inflammatory process. It is usually done alongside other tests rather than by itself.
- Sample type
- blood
- Category
- Anemia & Iron
- Turnaround
- 1-3 business days
- Price
- $49
- Referral
- Not required
An ESR (erythrocyte sedimentation rate) test measures how quickly red blood cells settle to the bottom of a tall, thin tube of blood. It is a general marker of inflammation in the body, so it is often ordered when a clinician suspects infection, an autoimmune condition, or another inflammatory process. It is usually done alongside other tests rather than by itself.
What it measures
- Erythrocyte sedimentation rate — The distance red blood cells fall in one hour, reported in millimeters per hour (mm/hr).
- Inflammation signal — A faster fall generally suggests more inflammation, but it does not show where inflammation is or what is causing it.
- Comparison to reference range — Your number is compared with a range that varies by age and sex.
Who it is for
An ESR is commonly ordered by primary care clinicians, rheumatologists, and other specialists when symptoms such as joint pain, fever, or fatigue suggest inflammation. It may also be used to help monitor a known inflammatory condition over time.
Preparation
No fasting or special preparation is usually required. Tell the clinician about medications, pregnancy, or recent illness, since these can affect the result.
Results and what they mean
Results are reported as a number in mm/hr and compared with a reference range that depends on age and sex. A higher value can occur with many conditions, so it is interpreted together with your symptoms, exam, and other tests. This is general information, not medical advice; only a qualified clinician can interpret your result and decide what it means for you.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the esr test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Does a high ESR mean I have a specific disease?
No. ESR is a nonspecific marker. Many conditions can raise it, and a clinician uses it with other findings to narrow down the cause.
Can I eat or drink before the test?
Yes. Fasting is not required for an ESR test unless your clinician orders other tests that need it.
What can make my ESR higher besides inflammation?
Pregnancy, older age, anemia, and some medications can raise it. A clinician considers these factors when reading your result.
How soon will I get results?
Turnaround is typically 1 to 3 business days, though it may vary by lab and location.