What is Plasma Viscometry ?

Plasma Viscometry (PV) is the measurement of the viscosity of blood plasma. The end result is a number given in milliPascal seconds (m.Pas.s) - know as the PV, or plasma viscosity. 

Plasma viscosity testing is an easy-to-use, rapid, and stable diagnostic tool for screening and monitoring patients with conditions including rheumatoid arthritis, myeloma, macroglobulinaemia and plasma hyperviscosity.

Interpretation of PV Results

Plasma viscosity is a non-specific screening test used in diagnosing a host of disorders. Unlike other investigations performed for non-specific symptoms, viscosity results can be grouped into broad bands to give an indication of the underlying condition, as summarised below:


PV range (mPa.s.)

Reported at 25ºC

PV range (mPa.s.)

Reported at 37ºC

Normal Range 1.50-1.72 1.12 - 1.27  
Low results < 1.40 < 1.05 Found in infants under 3 years old and patients with low immunoglobulin or fibrinogen levels.
High results 1.75 - 2.00 1.30 - 1.46 Chronic disorders e.g. infection, malignancy, vascular disease. Autoimmune such as rheumatic diseases.
Very high results 2.01 - 3.00 1.47 - 2.18 Suggestive of Myeloma. IgG-paraproteins.
High concentration of asymmetric paraproteins
Extremely high results > 3.00 > 2.18 Suggestive of Waldenstrom's macroglobulinaemia. 
Grossly raised IgM-paraproteins.

The above is a very basic summary and more information is available
in Articles and Guidelines  and Links to other websites 

Where is Plasma Viscosity used as a Diagnostic Tool?

Web Bar Chart

Chart : Customer reported usage of PV in screening tests

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Benson Viscometers pride themselves on the support and maintenance of the BV200 or BV1 plasma viscometers.
BV1 Unit
For confidence in your results

An increasing number of laboratories are electing to use Plasma Viscosity routinely in preference to erythrocyte sedimentation testing (ESR). This is because Plasma Viscosity results are easier to imterpret and results can be fully validated.

What They Say

"Benson Viscometers is the UK leader for plasma viscosity testing systems and we have had a long relationship with Bernie Benson. The BV1 is superbly engineered and easy to use, with a modified PC cabinet and a small footprint. Customer support is second to none." Graham Gibbs MSc CSci FIBMS, Lead Biomedical Scientist, Haematology Dept., Musgrove Park Hospital.

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BV200 Unit
Some PV Facts
  • Patient plasma viscosity (PV) is unaffected by patient anaemia or polycythaemia 
  • Samples can be analysed up to one week after centrifugation 
  • Test results are not affected by anti-inflammatory drugs 
  • Patient PV is not affected by age (>3 years), gender or smoking 
  • A rise of PV in the third trimester of pregnancy is predictable 
  • The only diagnostic test for plasma hyperviscosity