. Author manuscript; available in PMC: 2009 Jun 17.

Published in final edited form as: Ther Adv Cardiovasc Dis. 2008 Apr;2(2):79–88. doi: 10.1177/1753944708089696

Table 1.

Measures of capillary structure and function.

Capillary density = number of capillaries per square millimeter (mm²) of finger nailfold skin

(A) Resting baseline: continuously perfused capillaries [Serne et al. 2001]

(B) Postocclusive reactive hyperemia: continuously perfused + intermittently perfused (functional reserve) capillaries; measure of capillary function [Serne et al. 2001]

(C) Venous occlusion (maximal capillary density): maximal visualization of all capillaries present, including both perfused (with active red blood cell (RBC) motion) and nonperfused (filled with stagnant, non-moving RBCs) capillaries; measure of capillary structure [Antonios et al. 1999c]

Percent capillary recruitment = (B-A) ÷ C × 100

[Postocclusive reactive hyperemia capillary density – resting baseline capillary density]

Maximal capillary density (during passive venous congestion)

Measure of capillary function

Percent perfused capillaries = (B÷C) × 100

Postocclusive reactive hyperemia capillary density

Maximal capillary density (during passive venous congestion)

Measure of capillary function