What If the Erythrocyte Sedimentation Rate (ESR) Is Too Slow? New Parameters. New Explanations. New Applications

The erythrocyte sedimentation rate (ESR) is one of the oldest diagnostic tools already known by the ancient Greeks. When blood is placed in a tube, a phase separation between blood plasma and the remaining part of the blood containing the cells appears. The distance between the top of the liquid and the phase boundary determines the sedimentation height. Fast sedimentation, typically the height measured after one hour, is an unspecific parameter indicating inflammation. However, there is more to ESR than a single value for the sedimentation height. We investigated the physical dynamics of the cell aggregation occurring during erythrocyte sedimentation and devised a novel explanation. The formation of rouleaux actually extends to the formation of a percolating gel. Therefore, it is not the aggregate size that determines ESR but the permeability of this gel. The collapse of this gel is the base of the ESR. Hence the process of erythrocyte sedimentation can be described by a set of parameters determined by this gel. In addition to differences in height, the delay time, the maximal sedimentation speed and the final compaction resemble the most important ones.

In contrast to common clinical practice, where only a fast ESR is associated with pathologic conditions, we identified diseases and circumstances when the ESR is significantly slower. This includes the ESR of Sickle Cell Disease (SCD) patients, Chronic Mountain Sickness (CMS) patients, patients suffering from the Neuroacanthocytosis Syndromes (NAS) on the one hand and endurance elite athletes and highlanders on the other hand.

Significant differences can be detected between healthy controls and the patients listed using the aforementioned parameters. However, diagnostic value is only given if a clear discrimination between patients and healthy controls is possible. We found such discrimination for NAS patients with 8% false negative and 11% false positive among healthy controls. For differential diagnosis, we also tested patients with neurodegenerative diseases different from NAS, namely Parkinson's disease patients, Huntington's disease patients and amyotrophic lateral sclerosis patients. None of them showed a difference in the ESR compared to healthy controls, but all of them presented a significant difference to NAS patients.

Considering the low expenses required for ESR measurements and that they are automated in many central laboratories on the one hand and the difficulty and often very late diagnosis of NAS (sometimes years after the onset of symptoms), we recommend an ESR screening for NAS (slow sedimentation) as a routine in the frame of ordinary health checks of adults.

No relevant conflicts of interest to declare.