ESR, the erythrocyte sedimentation rate or "sed rate", measures how fast red blood cells settle in a tube over one hour. A high ESR is a non-specific sign of inflammation: it tells you something may be going on, not what. It also rises naturally with age, in women, in pregnancy and with anaemia, so a mildly high result is often not a concern on its own.
| Category | Reference range |
|---|---|
| Men, rough upper limit | age ÷ 2 mm/hr (mm in the first hour) |
| Women, rough upper limit | (age + 10) ÷ 2 mm/hr (mm in the first hour) |
| Example: woman aged 50 | up to about 30 mm/hr (mm in the first hour) |
| Example: man aged 40 | up to about 20 mm/hr (mm in the first hour) |
These are rules of thumb; labs print their own ranges, often by age and sex. Use the range on your report.
When there is inflammation, the liver releases proteins such as fibrinogen into the blood. They make red cells stick together in stacks, which sink faster, so the ESR goes up. Because many things change these proteins and the red cells themselves, the ESR is sensitive but not specific.
Doctors mainly use it in two ways: to support a suspicion of an inflammatory condition, and to follow conditions where it tracks activity well, such as polymyalgia rheumatica and giant cell arteritis.
A raised ESR has many possible explanations, and several can be present at once. These are the main groups doctors consider, from the everyday to the less common:
It depends on who you are. For a woman of 50 the rough upper limit is about 30, so 30 sits at the edge of normal. For a man of 30 the limit is around 15, so 30 is clearly raised. Mild elevations of 20–40 with no symptoms are common and are often simply rechecked after a few weeks, especially after a recent cold.
Very high values, above about 100 mm/hr, are treated differently: they are usually explained by a significant infection, an inflammatory condition or, less often, myeloma, and are investigated promptly.
CRP is the other common inflammation test. It rises and falls within a day or two, while ESR changes over days to weeks. That timing explains many mismatches: early in an infection CRP may be high while ESR has not caught up; during recovery CRP may have fallen while ESR is still high.
A high ESR with a persistently normal CRP may also reflect things that affect ESR but not CRP, such as anaemia, pregnancy, kidney disease, high levels of antibodies in the blood, or, less commonly, myeloma or lupus. Your doctor uses both tests together with your symptoms rather than either one alone.
A raised ESR should be reviewed by the doctor who ordered it. Seek urgent medical help (NHS 111, urgent care, A&E or the emergency room) if a high ESR comes with:
Written using public information from:
No need to decode the numbers yourself: take a photo of the report and the app explains “High ESR” and the rest in plain words — what is normal and what deserves attention.
App StoreGoogle PlayWeb versionThat there may be inflammation somewhere in the body. It is not specific, so your doctor reads it together with symptoms and other tests such as CRP and the full blood count.
It increases with age. A common rule of thumb for the upper limit is (age + 10) divided by 2, so about 20 at age 30 and about 35 at age 60. Your lab's own range is the one to use.
Not necessarily. For an older woman it can be within normal limits; for a young man it is mildly high. On its own, with no symptoms, it is usually rechecked rather than investigated straight away.
A recent infection, even a mild one, can raise ESR for several weeks. Everyday stress is not a recognised cause.
Yes. Sed rate is the common US name and ESR is the standard abbreviation, both for erythrocyte sedimentation rate.
This material is for general information only. It is not a medical opinion and does not replace a consultation with a doctor. Reference ranges depend on the laboratory and the method — rely on the range printed on your own report. Your doctor makes the final interpretation.
Ponyatno