Finding the right tests…
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Finding the right tests…
Haematology
ESR measures how fast your red blood cells settle to the bottom of a thin vertical tube over one hour, reported in millimetres. It does not test for any specific disease - it is an indirect sign of inflammation, because inflammatory proteins in the blood make red cells clump together and fall faster than they normally would. A normal reading in a young man is under 15 millimetres an hour; the number climbs naturally with age and runs higher in women than men at every age band. Doctors order it when symptoms like unexplained fever, joint pain or muscle aches suggest inflammation somewhere in the body, but do not yet point to a specific cause.
The result is a single number in millimetres per hour - how far the red cells have fallen in a standing tube after sixty minutes. Reference ranges are usually split by sex and age: roughly under 15 mm/hr for men under 50, under 20 mm/hr for men over 50, under 20 mm/hr for women under 50, and under 30 mm/hr for women over 50. A higher number means faster settling, which usually, though not always, means more inflammation.
ESR rises with inflammation from almost any cause - infection, autoimmune disease, some cancers, even pregnancy. That breadth is exactly why it cannot diagnose a specific condition on its own. A high result tells your doctor that something inflammatory is likely going on; it does not say what.
Because it is simple and inexpensive, ESR works well as a first check when symptoms are vague, and as a way to track whether a known inflammatory condition, like rheumatoid arthritis, is flaring or settling over weeks to months. A falling ESR over repeat visits usually means treatment is working.
Anaemia, pregnancy and older age can all push ESR up without any inflammation being present, while some blood disorders can push it down even when inflammation exists. This is why it is rarely read alone.
- Unexplained fever, joint pain or muscle aches - Monitoring known inflammatory or autoimmune conditions - Investigating unexplained weight loss or fatigue - Working up suspected infection of bone or joints
Ask your doctor how your ESR result fits with your other test results and symptoms, since the number by itself rarely settles a diagnosis.
Roughly under 15 mm/hr for men under 50 and under 20 mm/hr for women under 50, rising with age for both. Ranges vary by lab and by testing method, so check the reference range on your own report.
Not necessarily. ESR is a general marker of inflammation, which can come from infection, autoimmune disease, some cancers or even pregnancy. It does not point to one specific cause on its own.
No. It can support a diagnosis already suspected from symptoms and other tests, or help track whether a known inflammatory condition is active, but it cannot diagnose arthritis by itself.
Red cell and protein differences between sexes affect how quickly cells settle. That's why laboratories use separate reference ranges for men and women, and further separate ranges for people over 50.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
Yes. ESR normally rises during pregnancy due to changes in blood proteins, which is why pregnancy is taken into account when a doctor interprets a raised result.
It depends on why it was ordered - a one-off unexplained symptom versus monitoring an ongoing condition. Ask your doctor how often you should expect to repeat it.