The effects of proficiency and bias on residents' interpretation of the microscopic urinalysis

Objective. This study aims to determine whether residents are influenced by clinical information when interpreting microscopic urinalysis (UA) and estimating the probability of a urinary tract infection (UTI), and to determine the accuracy and reliability of UA readings. Design. Residents estimated the UA white blood cell count and the probability of a UTI in vignettes using a fractional factorial design, varying symptoms, gender, and the white blood cell count on preprepared urine slides. Results. Individual-level results indicated a clinical information bias and poor accuracy. Seventeen of 38 residents increased the white blood cell count in response to female gender; 14 increased the white blood cell count in response to UTI symptoms. Forty-nine percent of the readings were inaccurate; agreement ranged from 50% to 67% for white and red blood cells and bacteria. Conclusion. Many residents gave inaccurate UA readings, and many readings varied with clinical information. A significant portion of residents needs assistance in objectively and accurately interpreting the UA.