Sandbox:Hematuria historical prospective

Birch and Fairley in their initial report of dysmorphism of urinary RBC as a guide to renal pathology regarded up to 2,000RBC/ml as being normal, however, in subsequent reports they regard up to 8,000 dysmorphic RBC/ml as normal. Others have regarded greater than 3,000 RBC/ml as abnormal regardless of RBC morphology.

Birch and Fairley regarded up to 8,000 dysmorphic cells as normal and accordingly exclude this amount when assessing urinary RBC with respect to morphology. They recommend investigation of the lower urinary tract in all patients with any normomorphic urinary RBC. Others assess the pathology to be glomerular if >80% RBC are dysmorphic and non-glomerular if >80% RBC are normomorphic and still others regard >10% dysmorphism to be indicative of glomerular bleeding. Thus, many patients assessed by the latter criteria as having glomerular bleeding would have lower urinary tract bleeding when assessed by the criteria of Birch and Fairley. The present study indicates that while patients with glomerulonephritis have significantly larger percentages of dysmorphic RBC, it is only useful as an adjuvant in diagnosis if the percentage exceeds >75%. At levels below this lower urinary tract bleeding remains a possibility.

Furthermore, the study demonstrates that dysmorphism of urinary RBC is a non-specific indicator of renal pathology and not indicative of purely glomerular disease as evidenced by the fact that patients undergoing renal biopsy had equivalent percentages of dysmorphic RBC both pre- and post-biopsy. Although the results from patients undergoing renal function testing are less rigorous, the fact that patients with glomerular or medullary pathology could not be separated according to the dysmorphism of urinary RBC, would underscore the need to be extremely cautious in labelling any patient's significant hematuna as of either glomerular or lower tract origin.