Increased whole body hematocrit: venous hematocrit ratio in diabetes mellitus, evidence of microcirculatory hemoconcentration.

Plasma volume and red cell volume were measured in 24 diabetic outpatients. From the blood volume measurements, the whole body hematocrit was derived, and the ratio between whole body hematocrit:venous hematocrit (WBH:VH ratio) was considered to represent an index of the difference in red cell distribution between small and large blood vessels. The WBH:VH ratio was increased in 9 out of 13 males and in 1 out of 11 females, being inversely correlated to the plasma volume (r = -0.51, p less than 0.001). Although the significance of these findings is far from clear, the occurrence of small vessel hemoconcentration in male patients with diabetes mellitus may be relevant to the pathophysiology of vascular complications of diabetes.