The erythrocyte sedimentation rate measures how quickly red cells settle in a column of blood over an hour. Settling speeds up when plasma proteins, chiefly fibrinogen and immunoglobulins, make the cells stack together, so the test is an indirect and slow-moving marker of inflammation. It says that something is going on, not what.
No readings for this marker yet.
A raised rate most often accompanies infection, tissue injury, chronic inflammatory and autoimmune conditions, and it can be markedly high in some rheumatological and blood disorders. It also rises with anaemia, pregnancy, ageing and simply with time after the inflammatory trigger, since it lags behind the event by days. Low values carry little meaning on their own and are occasionally seen with polycythaemia or abnormal red cell shape.
The result depends on how long the sample stood before analysis, on temperature and on red cell number and shape, so a borderline figure should not be over-read. It is interpreted next to C-reactive protein, which reacts within hours and falls quickly, and to fibrinogen, which is one of the proteins actually driving the sedimentation; a doctor reads the trio against the clinical picture.
Reference ranges are general adult values and depend on lab, assay, age and sex. For orientation, not diagnosis — discuss results with your doctor.