What is the significance of a negative urine dipstick for protein along with an elevated urine PCR?
The urine dipstick reacts to albumin and not to other nonalbumin proteins.
The most important condition that one can miss here is overflow proteinuria, due to Ig light chains (Bence Jones proteins) from multiple myeloma. It may also be seen with tubular proteinuria.
In these cases, there is a discrepancy between the urine albumin-to-creatinine ratio, which may be low or normal, and the urine PCR, which will be elevated.
