What should you know about a high ESR blood test?

ESR, or erythrocyte sedimentation rate, measures how quickly red blood cells settle in a tube. Inflammation can change blood proteins and make cells settle faster. The result can be influenced by age, pregnancy, anaemia, kidney problems, recent infection and other factors, so the number needs clinical context.

A raised result may occur with conditions such as anaemia, chronic kidney disease, coeliac disease, Crohn's disease or an infection. It may also rise during recovery from an illness. ESR is a broad marker rather than a diagnosis, and a normal result does not exclude every inflammatory problem.

Arrange a review with the clinician who requested the test. Take the report and mention fever, pain, weight change, tiredness, bowel symptoms, joint stiffness, recent travel or a new medicine. The clinician may compare ESR with your examination and other blood results, then decide whether repeat testing or a targeted assessment is useful.

Do not start antibiotics or anti-inflammatory treatment solely because ESR is high. Focus on fluids, rest and the treatment already advised for any known illness. If the result was found during monitoring, ask when it should be checked again.

Seek urgent medical help for severe breathing difficulty, chest pain, confusion, fainting, sudden weakness, a severe headache with visual change, or a rapidly worsening illness. Contact a clinician promptly for persistent fever, unexplained weight loss, marked weakness, blood in stool, or pain that is worsening.

Ask: What was the ESR value and the laboratory reference range? Could anaemia, kidney disease, infection or another factor affect it? Which symptoms matter most? Do I need another test, treatment, or a repeat measurement?