RESUMO
Objective To evaluate the interference of occult blood in urine (urinary hemoglobin) and to determine the protein in urine by benzethonium chloride .Methods By reference to EP7‐A2 of CLSI ,urine containing different concentrations of hemoglobin were preparated to produce the dose‐effect curve,while 50 cases of clinical urine with varying degrees of occult blood were col‐lected for clinical sample bias test.Urinary protein was quantified by benzyl chloride in DPP roche comparing with sulfosalicylic acid method .Results When the urinary hemoglobin was 0 .2 g/L or higher ,the determined result of urinary protein of urinary pro‐tein would be significantly interfered by benzethonium chloride method .The clinical sample bias testshowed that clinical urine with different degrees of occult blood caused positive interference to the determination of protein by benzethonium chloride .Conclu‐sion Urine samples with occult blood and /or containing red blood cells should be emphasized and evaluate the accuracy when the urinary protein is quantified by benzyl chloride .If necessary ,it should be confirmed by sulfosalicylic acid .