Erythrocyte Sedimentation Rate (ESR) Interpretation and Correction

Summary: • Typical clinical scenario: elderly patient with an erythrocyte sedimentation rate (ESR) of 100 mm/hr > temporal artery biopsy to evaluate for giant cellarteritis o Do general exam, urine analysis, chest x-ray, serum protein electrophoresis, CBC, etc. o ESR is not specific but if >100 mm/hr, then something's usually wrong o Also, correct for age and hematocri t• Two ESR corrections to make, based on: o Age > Men: age/2 > Women: (age+10)/2 > Example: For a 70 year old female, 40 mm/hr is the starting point for ESR, not 0 mm/hr. o Hematocrit > Especially if moderate or severe anemia (a mild anemia will not change ESR to a clinically significant degree) > Use the Fabry equation: corrected ESR = Westergren sed rate * 15 / (55-hematocrit) • Use the ESR in combination with C reactive protein and platelet count o If all 3 are in the same direction (e.g. all elevated), then sensitivity and specificity of ESR is increased o If ESR is elevated, CRP is normal, and platelet count is normal, ESR could be elevated due to some other globulin or some other reason to have fibrinogen increase other than temporal arteritis