Would you recommend proceeding with a kidney biopsy for patients' with Waldenström's macroglobulinemia who have hematuria and normal kidney function?

The answer to this question would certainly depend on the clinical scenario.

As we are aware, there are many different etiologies of hematuria. If the patient were to have gross hematuria, then I would start with cross-sectional imaging to ensure there is no nephrolithiasis or tumor and even consider...

I agree with Dr. @Dr. First Last.

The presence of renal impairment or any proteinuria would lead me to biopsy in the presence of microhematuria.

Also, if there are significant systemic symptoms and the decision to treat hinges around renal involvement, I would recommend a kidney biopsy.