If a patient has unexplained renal disease, and this could be interstitial or glomerular, and an MGUS, I strongly consider it. I typically try to get heme to do a bone marrow biopsy first because their findings may obviate a renal biopsy if they find something (although sometimes they may find low-g...

In my practice, I am aggressive in looking for MGRS in MGUS patients with changes in uPCR (especially if uMACR is unchanged because it suggests the increased proteinuria is non-albumin, which makes light chain proteinuria a possible culprit). In these cases, I do push for kidney biopsy because the p...