Plasma Viscosity

Blood Sciences Test

---

Recommendations for inflammatory marker testing in Devon from May  2022: C-Reactive Protein (CRP) should be your first line inflammatory marker test of choice

There are few scenarios where good clinical correlation with (or without) a CRP cannot guide patient management. If a second line inflammatory marker is required, as per the indications below, please request a  Plasma Viscosity (PV).

Erythrocyte Sedimentation Rate (ESR) will no longer be available to request this.

PV should not be requested for routine situations.  Ordercomms  (ICE) will be set up to allow specification of PV request rationale:

• If temporal arteritis (TA)/giant cell arteritis (GCA) or hyperviscosity syndrome is suspected, then PV, although not necessary, may be requested. Appropriate management of these indications should not be delayed while results are pending.
• If a systemic inflammatory illness such as rheumatoid arthritis or systemic lupus erythematosus is suspected and CRP is normal, then PV may be appropriate to establish a baseline for monitoring.
• If CRP has been shown to inadequately reflect disease activity in a patient with established chronic inflammatory illness (such as rheumatoid arthritis or systemic lupus erythematosus), then monitoring with PV will be appropriate.

Specimen

Whole blood EDTA

Special Instructions

Test performed from FBC tube provided it is not underfilled. These tubes are retained for 48hrs therefore a PV can normally be added after sample receipt if required.

Paediatric Samples: If an adult tube cannot be used please use the 1.2mL monovette (similar to the above tube but a smaller diameter).

Screw top microtubes are not suitable.

Factors affecting results

Clotted samples cannot be tested

Reference Ranges

1.50 – 1.72 mPa.s

From: Chanarin I Laboratory Haematology 1989

Test Usage

 

Interpretation of results – Reference range 1.50 – 1.72 mPa.s (milli Pascal seconds)
Low results	<1.50	Found in infants under 3 years old and patients with low immunoglobulin or fibrinogen levels.
High results	1.75 – 2.00	Found in many chronic disorders e.g. infection, malignancy, collagen vascular disease.
Very high results	2.01 – 3.00	Suggestive of myeloma.
Extremely high results	>3.00	Suggestive of Waldenstrom’s macroglobulinaemia.

Turnaround time

1-2 days

Availability

In house

Clinical Advice

Clinical advice is available from the Haematology Medical team (contact RD&E switchboard on 01392 411611)

Specimen Labelling Procedure