Erythrocyte Sedimentation Rate, use in Nephrology?

from http://www.pexels.com

During my residency, ESR was a common investigation requested during initial kidney patient assessment. A cut-off value around 100 mm/h was the one that draws nephrologists attention to search for a hidden cause for the patient’s kidney disease. During my fellowship, i learned some arguments against the common use of ESR, with its low sensitivity. This kept me skeptical about its use. Here, i am going to highlight a recent article published in JAMA evaluating the use of ESR through a case based scenario.

First of all, ESR measures the rate at which RBCs settle in the plasma of anti-coagulated blood in a standardized Westergren tube.

ESR is a measure of inflammation caused by infection, malignancy, or rheumatologic diseases. However, multiple non-inflammatory causes can affect the ESR including anemia, hypergammaglobulinemia, hypoalbuminemia (those increase ESR), polycythemia, leukocytosis, hyperbilirubinemia and hypercholesterolemia (can decrease ESR).

ESR has poor sensitivity and specificity in low cut-off values, however specificity and sensitivity increase as the cut-off increase, with specificity for hidden disease reaching more than 90% in some studies when using values greater than 100 mm/h.

Common causes of an ESR > 100 mm/h include:
1. Deep seated infections (osteomyelitis or endocarditis)
2. Connective tissue disorders
3. Malignancy

With all what was said in mind, we can conclude that ESR greater than 100 mm/h deserves diagnostic attention but is nonspecific and cannot by itself establish a diagnosis.

Mohamed Elrggal
23 March 2019