This document outlines a module on erythrocyte sedimentation rate (ESR). The module is part of a general physiology course for medical laboratory technology students. It will teach students how to perform ESR, packed cell volume, and blood cell function tests. Specifically, the module will cover the principle and mechanism of erythrocyte sedimentation, factors affecting ESR, methods for estimating ESR, the clinical significance of ESR, and sources of error in the ESR test. The module contents include ESR tubes and abnormalities.