Is the relative 99mTc-DMSA clearance a useful marker of proximal tubular dysfunction?

The clearance of 125I-sodium iothalamate, 131I-sodium hippurate, 99mTc-DMSA, and beta 2-microglobulin were determined in 20 patients with proven or suspected proximal tubular dysfunction and in 18 control patients with various renal diseases. A clear distinction in the relative 99mTc-DMSA clearance was observed between patients with proximal tubulopathy (14%-35%) and control patients (less than 14%). A similar difference between the two groups was found in the relative beta 2-microglobulin clearance. Nine patients with proximal tubulopathy showed an elevated filtration fraction versus only two control patients. The renal handling of 99mTc-DMSA seems to be an indicator of proximal tubular function.