Urine Protein Cases Key

Case 1

2+ protein with a very dilute urine specific gravity of 1.004 is likely significant. The proteinuria in this case is not secretory (post glomerular) because of the low number of cells in the sediment. It may be due to functional causes such as exercise or seizure activity or to overflow of small proteins increased in blood such as Bence Jones proteins from a plasma cell tumor. It is not overflow of hemoglobin as the reading for blood is negative. It could possibly be due to intrinsic renal tubular disease, although this patient is demonstrating an ability to dilute its urine outside the isosthenuric range which demonstrates tubular work and there are no other indicators of tubular dysfunction such as glucosuria. Therefore, a tubular cause for the proteinuria is unlikely. Additional diagnostics should include a repeat urinalysis to see if the proteinuria persists and if persistent, then the proteinuria should be assessed utilizing a urine protein to creatinine ratio. Serum should be evaluated for increased total serum proteins to exclude the presence of a plasma cell tumor.

Case 2

3+ protein with a 1.035 urine specific gravity would likely be significant if it were accurate. It is possible that it is a false positive reading due to the alkaline urine pH. This sample should be repeated using a turbidometric method. If the pH remains alkaline, then a urine protein to creatinine ratio should be performed to determine if the protein is real.

Case 3

2+ protein with a 1.060 urine specific gravity is a small amount of protein. It is likely secretory (post glomerular) in origin because of the high numbers of white cells (pyuria) and red cells (hematuria) in the urine. These sediment changes are more compatible with inflammation or infection than with just hemorrhage as the ratio of red cells to white cells is not in the approximate proportion of red cells to white cells in blood. (500 RBC:1 WBC)