Performance of a Urine-Screening Protocol

Abstract

The performance of a urinalysis protocol using screening Chemstrip-9 dipstick analysis with selective sediment microscopy and culture is reviewed. Sediment microscopy performed on urine samples positive for leukocyte esterase, nitrite, protein, or blood, or when specifically ordered (15% of urinalyses) was reduced by 57.1%. Protocol urine culture performed when more than 5 WBC/high-powered field (HPF), more than 10 bacteria/HPF, or yeasts were found on sediment microscopy or with a positive nitrite test was done for 9.8%. Urine culture was specifically ordered for another 13.6%. Percent significant bacteriuria (greater than or equal to 10(5) colony-forming units/mL) was higher for protocol-generated cultures (37.1%) versus ordered cultures (17.2%). For urinalyses with ordered cultures, the protocol would have detected 89.8% of cases with significant bacteriuria. The protocol has facilitated detection of significant bacteriuria with good acceptance by clinicians. Cost savings achieved by reduction of sediment microscopy was partly off-set by some increase in urine cultures performed.

Screening Urine Specimen Populations for Normality Using Different Dipsticks: Evaluation of Parameters Influencing Sensitivity and Specificity

“…In some of these studies, samples investigated after presentation to the routine laboratory had been collected without special precautions to ensure sterile conditions (2,6,8,15,18,23,24). In others, special care was taken, such s the use of sterilized Containers and collection of clean voided, midstream or catheter urine (5,7,12,13,14,22).…”

“…screening protocols were related to standardized microscopy (4,18,23,24,25), whereas in others routine procedures were used (8,13). From the present study i t appears that performance of microscopy and choice of cut-off values greatly influences the values for sensitivity and specificity.…”

Qual o valor da sedimentoscopia em urinas com características físico-químicas normais?

“…Em outros países, há muito se procurou simplificar o exame, abolindo-se a análise do sedimento sempre que o exame físico mostra uma urina límpida, de coloração normal e o exame químico, realizado com tira reagente, não revela anormalidade (1,2,3,5,6,7,11,12,13,15). Tal norma foi adotada desde que respeitadas as características da clientela própria de cada serviço e as exigências da requisição médica (10,15).…”