An automated tube-type blood viscometer: Validation studies

T. Alexy, R. B. Wenby, E. Pais, L. J. Goldstein, W. Hogenauer, H. J. Meiselman

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


The technical complexity of previous rheometers has tended to limit the availability of blood viscosity data obtained over a wide range of shear rates. However, an automated tube-type viscometer, the Rheolog™, has been developed; it employs a disposable flow assembly and less than five minutes are required to obtain blood viscosity results over a shear rate range of 1-1500 s-1. We have carried out validation studies of the Rheolog™ using normal human blood and have compared these results with those obtained by cone-plate and Couette viscometers; storage time and temperature effects were also evaluated. Replicate measurements indicated mean CV levels less than 5%, and were independent of hematocrit and shear rate. Rheolog™ blood viscosity data agreed closely with those from other viscometers: average Rheolog™ differences from mean cone-plate and Couette values were -0.3% at 28% hematocrit, -1.4% at 41% hematocrit (i.e., native), and 1.0% at 56% hematocrit. Storage at room temperature up to 8 hours and at 4°C up to 4 days had minimal effects whereas notable changes were observed when stored for 3 hours at 37°C. Our results indicate that, within the hematocrit and shear rate limits employed herein, the Rheolog™ provides rapid, accurate and reproducible blood viscosity data, and suggest its usefulness for both basic science and clinical studies.

Original languageEnglish (US)
Pages (from-to)237-247
Number of pages11
Issue number3
StatePublished - 2005


  • Blood
  • Rheolog
  • Shear rate
  • Viscometer
  • Viscosity


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