Different laboratories recently reported incongruous results describing the quantification of
albumin filtration using two-photon microscopy. We investigated the factors that influence the
glomerular sieving coefficient for albumin (GSC A) in an effort to explain these discordant
reports and to develop standard operating procedures for determining GSC A. Multiple
factors influenced GSC A, including the kidney depth of image acquisition (10–20 μm was
appropriate), the selection of fluorophore (probes emitting longer wavelengths were …