Health sectors around the world are continually improving diagnostic practices in hospital laboratories to provide clinicians with faster and more reliable information. One notable development has been the gradual transition from the traditional erythrocyte sedimentation rate (ESR) test to plasma viscosity (PV) as a preferred marker of inflammation.
Such a change is occuring across a wide network of hospitals, with adoption seen in regions such as the north-east of Scotland and the south-west of England, among many others. This shift reflects increasing recognition that plasma viscosity offers more reliable and accurate results reflecting true in-vivo conditions.
For many years, ESR was widely used to detect inflammation and infection. However, clinicians and laboratory scientists have recognised limitations with the test. ESR results can be affected by factors unrelated to disease activity, such as red blood cell concentration, medications, sample handling, temperature variations, and physiological stimuli (lifestyle, smoking, weight and blood pressure). These influences can sometimes lead to inaccurate, misleading or inconclusive results, making it harder for clinicians to interpret disease severity or progression.
Plasma viscosity (PV) testing provides a more stable alternative to ESR. PV gives a measure of the acute phase response rather than relying on how red blood cells settle in a sample. The viscosity of plasma changes in proportion to the concentration and molecular size of plasma proteins such as fibrinogen, immunoglobulins and paraproteins, which increase as part of the body’s natural response to infection, inflammation, or tissue injury. PV focuses on plasma rather than red blood cells. Therefore, the results are less affected by variables such as haematocrit or cell shape, making the test more reproducible and reliable.
Hospitals are increasingly adopting PV testing within routine laboratory services. Already many laboratories have incorporated plasma viscosity as a routine inflammatory marker and encourage clinicians and general practitioners to request PV instead of ESR. The PV test result often becomes abnormal earlier in the course of disease and provides a clearer indication of inflammatory activity.
Operational advantages have also supported the move towards plasma viscosity. PV testing can be performed using standard EDTA blood samples, meaning it can often be carried out on the same blood sample used for a full blood count. Modern clinical viscometers allow laboratories to process multiple samples efficiently while maintaining strong quality control, helping laboratories manage high workloads while delivering dependable results.
For clinicians, plasma viscosity offers reliable results for diagnosing and monitoring conditions associated with infection, inflammation and trauma. These include multiple myeloma, Waldenstrőm’s macroglobulinaemia, hyperviscosity syndrome, temporal arteritis, polymyalgia rheumatica, rheumatoid arthritis, cardiovascular disease, COVID-19, dementia and vascular complications linked to diabetes. The improved consistency of PV results helps clinicians make better-informed decisions about diagnosis, treatment, and ongoing patient monitoring.
As healthcare systems continue to prioritise early detection and proactive disease management, plasma viscosity testing is becoming an increasingly important diagnostic tool. By providing accurate, repeatable insight into inflammatory processes within the body, PV testing supports better patient care while improving laboratory efficiency.
Benson Clinical Viscometers is helping laboratories adopt reliable alternatives to traditional tests like ESR and supporting the evolving needs of modern healthcare.
Visit the company at Stand 33 during the British Society for Haematology Annual Scientific Meeting, 19-21 April 2026, at the ACC, Liverpool.
Learn more at https://bensonviscometers.com/