|Measurement of Erythrocyte Sedimentation Rate with Westergren-method (Photo credit: Wikipedia)|
The ESR is increased by any cause or focus of inflammation. The ESR is increased in pregnancy, inflammation, anemia or rheumatoid arthritis, and decreased in polycythemia, sickle cell anemia, hereditary spherocytosis, and congestive heart failure. The basal ESR is slightly higher in females.
The ESR is governed by the balance between pro-sedimentation factors, mainly fibrinogen, and those factors resisting sedimentation, namely the negative charge of the erythrocytes (zeta potential).
When an inflammatory process is present, the high proportion of fibrinogen in the blood causes red blood cells to stick to each other. The red cells form stacks called 'rouleaux,' which settle faster. Rouleaux formation can also occur in association with some lymphoproliferative disorders in which one or more immunoglobulins are secreted in high amounts.
Raised ESR is common marker of Inflammatory diseases, collagen disease, autoimmune diseases and cancer. Sometimes, no obvious cause is found by the usual investigations for a raised ESR that poses difficulty in diagnosing the underlying disease.There is also no agreed protocol for how to proceed from here.
Normal ESR is 1-25 mm/1st hour in female and 0-17 mm/1st hour in male. Widely used formula for calculation of normal value of ESR in adults that varies according to age is; in male less than or equal to Age/2; in female (age+10)/2.
In a research article published in the PLOS ONE by Lensen K-JDF et al conclude that 18F-fluorodeoxglucose positron emission tomography (PET/CT) can be very helpful in diagnosing the such a non-obvious disease.
After use of conventional investigations like ultra sonogram, CT, X-Rays, MRIs and routine blood tests, if no diagnosis is forthcoming, they suggest FDG/PET/CT.
In this way, they have established diagnosis of Large vessel vasculitis like Giant Cell Arteritis, malignancy and autoimmune diseases in otherwise undiagnosed cases of raised ESR.