Are quantitative attenuation measurements of blood by optical coherence tomography feasible?

We present optical coherence tomography (OCT) measurements on fully physiologically oxygenated blood samples of varying hematocrit. We show that attenuation coefficients cannot be extracted quantitatively using the currently accepted models for the OCT signal from scattering media, because the confidence intervals obtained in the fitting procedure cannot be used as reliable uncertainty estimates of the attenuation coefficients. Better modeling of the hematocrit-dependent OCT signal is needed.