Whole blood viscosity assessment issues IV: Prevalence in acute phase inflammation

BACKGROUND: Hyperviscosity syndrome has been suggested as not simply an acute reaction. Yet, erythrocyte sedimentation rate is associated with whole blood viscosity and it is an indirect acute phase inflammation marker. AIMS: This work investigates the prevalence of hyperviscosity in acute phase inflammation. MATERIALS AND METHODS: Archived clinical pathology data for the period of 1999 to 2008 were utilized. 40,632-cases tested for C-reactive protein and/or erythrocyte sedimentation rate from five alternate years, which were concomitantly tested for haematocrit and total proteins, were extracted. The prevalence of abnormal viscosity associated with positive results of C-reactive protein and erythrocyte sedimentation rate were evaluated. RESULTS: Hyperviscosity is infrequently associated with positive C-reactive protein (2.9%) and erythrocyte sedimentation rate (2.7%) sub-populations, and are not statistically different from their respective negative sub-populations. Normoviscosity is significantly more prevalent in the positive sub-populations (p < 0.01). Further analyses indicate that prevalence of acute phase inflammation is statistically significantly less in hyperviscosity compared to normoviscosity sub-population (p < 0.00001). Actual blood viscosity level increases with level of inflammation though. CONCLUSION: The study demonstrates that although blood viscosity level may increase with inflammation, hyperviscosity is not frequent in, or sensitive to acute phase inflammation. It portends that whole blood viscosity is not unspecific as acute phase inflammation markers. It calls for clinicians to consider utilizing whole blood viscosity in disease conditions where stasis is implicated, in which it is specific and valuable. It would also benefit to establish whether hyperviscosity is a chronic phase inflammation marker.