ESR

Women: below 20 mm/h · Men: below 15 mm/h

The upper limit rises with age and is higher in women: a common rule of thumb used by UK laboratories is age divided by two for men, and age plus ten divided by two for women, so a figure in the 30s is within the usual range for many older adults. Ranges also differ in pregnancy.

The ESR measures how far red blood cells settle down a thin tube of blood in one hour. When there is inflammation, proteins in the blood make the red cells clump and fall faster, so the number goes up. It is an old, simple and slow-moving marker of inflammation that responds over days to weeks rather than hours.

Doctors request it, often alongside CRP, when looking for inflammation, for example in unexplained aches, joint pains, headaches in older people or tiredness, and to follow some long-term inflammatory conditions. It is also part of the tests used when looking at abnormal blood proteins.

• Infection and inflammatory conditions such as rheumatoid arthritis, polymyalgia and vasculitis
• Older age and being female, in the general population
• Anaemia, because fewer red cells settle faster
• Pregnancy
• Kidney disease and high blood protein levels, including myeloma
• Some cancers
• Being overweight, a little

• Settling of the inflammation that raised it, over weeks
• A high red cell count, as in polycythaemia
• Abnormally shaped red cells, as in sickle cell disease
• Heart failure and very high white cell counts
• Anti-inflammatory medicines and steroids

• It rises with age, so the fixed range on many reports is too tight for older adults
• Anaemia of any cause raises it without inflammation
• The sample has to be tested within a few hours; a delayed sample reads low
• Pregnancy raises it throughout

No fasting needed. The sample must be tested within a few hours of collection. Because it responds slowly, it lags behind CRP in both rising and settling, and the trend over weeks is more useful than one value.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.