The paper is aimed at differential diagnosis of increased sedimentation rate (ESR) from the point of internal medicine. After the interpretation of the term we describe the technique of the examination and possible errors in pre-analytical as well as analytical phase. The paper includes ranges for conventional FW assessment (analysis of ESR based on Fahraeus-Westergren) and the characteristics of newer methods. We list the overview of the most common causes that affect faster or slower ESR. The stress is put on the assessment of the causes of increased ESR and its persistence from the perspective of clinical practice, we also describe diseases with slower ESR. Attention is drawn to the comparison of the results of the most common acute phase reactants, especially to discordant results of ESR, CRP and procalcitonin in the serum, and to the contribution of the analysis of ESR and CRP in selected diseases. The final part is aimed at the correct diagnostic approach when assessing increased ESR of unknown etiology, underlining the significance of the patient´s history, physical examination and the position of basic as well as complementary laboratory methods and examinations including imaging techniques.
Keywords: C‑reactive protein; ESR of unknown etiology; Fahreus‑Westergren method; diagnostic approach; differential diagnosis of increased and decreased erythrocyte sedimentation rate; normal ESR ranges; presepsin; procalcitonin.