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Epic Test Code LAB765 Viscosity, Serum

Additional Codes

MML:SVISC


Specimen Required


Collection Container/Tube: Red top (serum gel/SST are not acceptable)

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL

Collection Instructions:

1. Keep specimen at 37° C (eg, 37° C Thermopak, heat block) until after centrifugation.

2. Centrifuge and aliquot serum into plastic vial.


Useful For

Detection of increased viscosity

 

Monitoring patients with hyperviscosity syndrome

 

This test is not useful for patients with small concentrations of monoclonal proteins.

Method Name

Capillary Measurement

Reporting Name

Viscosity, S

Specimen Type

Serum Red

Specimen Minimum Volume

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Red Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  14 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Clinical Information

Viscosity is the property of fluids to resist flow. Hyperviscosity may be manifested by nasal bleeding, blurred vision, headaches, dizziness, nystagmus, deafness, diplopia, ataxia, paresthesias, or congestive heart failure. Funduscopic examination reveals dilation of retinal veins and flame shaped retinal hemorrhages.

 

The most common cause of serum hyperviscosity is the presence of large concentrations of IgM monoclonal proteins, and Waldenstrom macroglobulinemia accounts for 80% to 90% of hyperviscosity cases. Hyperviscosity syndrome can also occur in multiple myeloma patients.

 

Because the ability of a monoclonal protein to cause hyperviscosity is affected by its concentration, molecular weight, and aggregation, sera with concentrations of monoclonal IgM greater than 4 g/dL, IgA greater than 5 g/dL, or IgG greater than 6 g/dL should be tested for hyperviscosity.

 

Serum viscosity and electrophoresis are recommended before and after plasmapheresis in order to correlate viscosity and M-spike with patient symptoms. This correlation may be useful for anticipating the need for repeat plasmapheresis.

Reference Values

≤1.5 centipoises

Interpretation

Although viscosities greater than 1.5 centipoises (cP) are abnormal, hyperviscosity is rarely present unless the viscosity is greater than 3 cP.

Cautions

Failure to follow specimen handling instructions may cause false-low results.

 

Hyperviscosity syndrome may not be present even if the viscosity is greater than 3 centipoises.

Day(s) Performed

Monday through Friday

Report Available

1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

85810

NY State Approved

Yes

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Benign Hematology Test Request Form (T755)

-Hematopathology/Cytogenetics Test Request (T726)