CRP, ESR and PV inflammation markers – a comparative review

Inflammatory markers are blood tests used by healthcare professionals to detect inflammation, which aid in the diagnosis and monitor the progression of many diseases.¹ After the total and differential white cell count, which are part of the full blood count (FBC), the three most commonly used general inflammation markers to screen the wide range of organic diseases are, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and plasma viscosity (PV). Numerous studies have highlighted advantages of each and conversely have also demonstrated limitations. The decision to commit to a particular test can therefore be an important one for clinicians and laboratory scientists, with many factors to consider, including the patient population being served. Hence, an overall review may assist in the final decision-making process. In addition to their role as inflammatory markers, CRP and PV have also both been used as predictors of cardiovascular disease risks. PV on the other hand, has been shown to be influential in the aid of diagnosis and monitoring progression of other disorders like diabetes, cardiovascular diseases, dementia, Alzheimer’s disease and COVID-19.

C-reactive protein

Discovered in 1930, the term CRP was derived from its initial identification as a substance present in the serum of patients experiencing acute inflammation, which exhibited a reaction with the ‘C’ carbohydrate antigen found in the capsule of pneumococcus.² CRP is a calcium-dependent acute phase protein of hepatic origin which binds to phosphocholine on the surface of dead or dying cells and some bacteria. It is now known to exist in at least three different forms: a monomeric (modified) form, a pentameric (natural or native) form and multimeric forms consisting of ten or more subunits.³ Other separate forms have been described such as dimers, trimers, tetramers and non-native pentameric forms.⁴ Clinicians are advised to exercise caution when making critical decisions based on the limited information provided by the CRP.