Hematocrit and Whole Blood Viscosity

 

The viscosity is from observed leukocrit and erythrocrit (Figure 1, page 726, Lichtman 1987; Figure 2, page 280, Lichtman 1982). Equations derived in JMP from points read from diagram. The viscosity associated with the hematocrit is linear in a semi-logarithmic plot and exponential in a non-logarithmic plot.

 

LOG10(viscosity due to erythrocrit) = X =

= (0.01138 * (hematocrit in percent)) + 0.03699

 

viscosity due to erythrocrit in centipoise =

= 10 ^ (X)

 

NOTE: For the influence of a very high white blood cell count (sufficient to give a measureable leukocrit) see 28.15.01.

 

If the equations are rewritten:

 

estimated hematocrit in percent for a given viscosity =

= ((LOG10(viscosity in centipoise)) - (0.03699)) / 0.01138 =

= (87.873 * LOG10(viscosity in centipoise)) - 3.25

 

In the Scientific Tables (Documenta Geigy) there is a graphical plot showing the correlation of hematocrit to blood viscosity from Pirofsky. This gives lower values than Licthman et al. if the plot is analyzed:

Hematocrit in percent	Viscosity in Centipoise
20	1.41
22.5	1.5
30	1.79
35	2
40	2.29
50	2.85
51.8	3
60	3.7
62.5	4
68.6	5
70	5.23
73.1	6
78.4	8
80	9

 

If this is modeled in JMP:

 

viscosity in centipoise =

= (0.00000205 * ((hematocrit)^4)) - (0.000339 * ((hematocrit)^3)) + (0.02077 * ((hematocrit)^2)) - (0.499 * (hematocrit)) + 5.513