BLOOD SCIENCES


accurate and useful screening test. The viscosity of plasma is determined by the concentration and size of proteins in the blood which increases as part of the body’s normal response to infection, inflammation, and due to the effects of traumatic injury.17


For a patient aged over


three years returning a PV tested at 37°C but reported at room temperature, 25°C will give a range of 1.50-1.72 mPa·s or reported at 37°C will give a range of 1.12- 1.27 mPa·s.18


Plasma viscosity is widely used by scientists and clinicians in diagnosing and monitoring a host of clinical conditions, most commonly:17 n Polymyalgia rheumatica n Rheumatoid arthritis n Temporal arteritis n Hyperviscosity syndrome n COVID-19 n Multiple myeloma n Waldenström’s macroglobulinaemia n Cardiovascular disease n Diabetes n Vascular dementia and Alzheimer’s.


Based on scientific studies, the plasma viscosity test is a robust and reliable tool that provides valuable insight into a patient’s health, particularly in relation to inflammatory and haematological conditions.19


Its advantages in terms of


stability, direct measurement, and minimal external factor interference make it a superior choice in detection of elevated proteins and also abnormal paraproteins in many clinical scenarios. Therefore, PV test is far more valid, accurate and sensitive than erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) tests.


Summary


Plasma viscosity test results are reliable, repeatable and reproducible. The benefits and rewards of PV testing are substantial, not only for our doctors and clinical services but for a patient’s clinical outcome.


Plasma viscosity can add useful


information in the diagnosis and treatment of various disorders. Therefore, plasma viscosity testing should be exploited and utilised more frequently in clinical medicine.


References 1 Simon RP, Aminoff MJ, Greenberg DA.


eds. Clinical Neurology, 10th edn. McGraw-Hill Education; 2017. https:// accessmedicine.mhmedical.com/content. aspx?bookid=2274&sectionid=176231202


2 Iadecola C. The pathobiology of vascular dementia. Neuron. 2013;80(4):844-866. doi:10.1016/j.neuron.2013.10.008 3 Dementia UK. Types of dementia.


36


n Considered scientifically superior and more reliable test than similar tests. n The normal range is consistent across genders. n Medication such as aspirin and steroids do not interfere with results. n Characteristics of myeloma and macroglobulinaemia are evident in the results. n Anaemia and polycythaemia do not affect or distort results. n Testing can be performed on sample up to seven days old.


Table 1. Advantages of plasma viscosity testing.20


(Dementia UK, 2024) https://www. dementiauk.org/information-and-support/ types-of-dementia/


4 National Institute for Health and Care Excellence. Dementia: What are the risk factors? (NICE, 2024) https://cks.nice. org.uk/topics/dementia/background- information/risk-factors/


5 Alzheimer’s Disease International. Warning signs of dementia infographic (ADI, 2017) https://www.alzint.org/resource/warning- signs-of-dementia-infographic/


6 Alzheimer’s Society. People with dementia face up to two year wait for diagnosis. (Alzheimer’s Society, 2022) https://www. alzheimers.org.uk/news/2022-09-23/ people-dementia-face-two-year-wait- diagnosis


7 Huang SS. Depression among caregivers of patients with dementia: Associative factors and management approaches. World J Psychiatry. 2022 Jan 19;12(1):59-76. doi:10.5498/wjp.v12. i1.59


8 World Health Organization. The top 10 causes of death. (Geneva: WHO, 2024) https://www.who.int/news-room/fact- sheets/detail/the-top-10-causes-of-death


9 World Health Organization. Dementia. (Geneva: WHO, 2023) https://www.who. int/news-room/fact-sheets/detail/dementia


10 GBD 2019 Dementia Forecasting Collaborators. Estimation of the global prevalence of dementia in 2019 and forecasted prevalence in 2050: an analysis for the Global Burden of Disease Study 2019. Lancet Public Health. 2022;7(2):e105-e125. doi:10.1016/S2468- 2667(21)00249-8


11 National Institute for Health and Care Excellence. Dementia: How common is it? (London: NICE, 2024) https://cks.nice. org.uk/topics/dementia/background- information/prevalence/


12 Otto C, Richter WO, Schwandt P. Contribution of fibrinogen and lipoproteins to plasma viscosity in hypercholesterolemia and hypertriglyceridemia: evaluation by selective depletion of low-density lipoproteins or fibrinogen. Metabolism. 2000;49(6):810-813. doi:10.1053/ meta.2000.6264


13 Lowe GD. Blood rheology in vitro and in vivo. Baillieres Clin Haematol.


1987;1(3):597-636. doi:10.1016/s0950- 3536(87)80018-5


14 Aras S, Tek I, Varli M, et al. Plasma viscosity: is a biomarker for the differential diagnosis of Alzheimer’s disease and vascular dementia?. Am J Alzheimers Dis Other Demen. 2013;28(1):62-68. doi:10.1177/1533317512467682


15 van Oijen M, Witteman JC, Hofman A, Koudstaal PJ, Breteler MM. Fibrinogen is associated with an increased risk of Alzheimer disease and vascular dementia. Stroke. 2005;36(12):2637-2641. doi:10.1161/01.STR.0000189721.31432.26


16 Marioni RE, Stewart MC, Murray GD, et al. Peripheral levels of fibrinogen, C-reactive protein, and plasma viscosity predict future cognitive decline in individuals without dementia. Psychosom Med. 2009;71(8):901-906. doi:10.1097/ PSY.0b013e3181b1e538


17 Tan S. Guidance on Plasma Viscosity (PV). (NHS Tayside, 2019) https:// www.nhstaysidecdn.scot.nhs.uk/ NHSTaysideWeb/idcplg?IdcService=GET_ SECURE_FILE&Rendition=web&RevisionS electionMethod=LatestReleased&noSave As=1&dDocName=prod_342415


18 Patient. Blood tests to detect inflammation. (EMIS, 2023) https://patient.info/treatment-medication/ blood-tests/blood-tests-to-detect- inflammation


19 The Leeds Teaching Hospitals NHS Trust. Plasma Viscosity (PV). (LTH NHST, 2024) https://www.leedsth.nhs.uk/services/ pathology/tests/plasma-viscosity-pv


20 Department of Haematology, Gloucestershire Hospitals NHS Foundation Trust. Plasma Viscosity. (Glos Hospitals NHS FT, 2024) https://www.gloshospitals. nhs.uk/our-services/services-we-offer/ pathology/tests-and-investigations/ plasma-viscosity/


David Norcliffe MMedSci, CSci (retired) FIBMS (retired) DM


David Manuel, BSc (Hons) Health Science, SP & IP (Prescribing), PGCert (Advanced Practice)


Article supplied by Benson Viscometers 01646 650065


sales@bensonviscometers.com www.bensonviscometers.com


DECEMBER 2024 WWW.PATHOLOGYINPRACTICE.COM


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