Can Urine Clarity Exclude the Diagnosis of Urinary Tract Infection? Date: 2002/6/28 黃錦鳳 / 黃玉純

Purpose Determine the association of clear urine by visual inspection with the absence of significant bacteruria and to compare it with standard urinalysis.

Methods ED of Children’s Hospital Medical Center < 21 years old children's Information recorded –Duration of fever –Abdominal pain or flank pain –Dysuria, Frequency, urgency –Age –Sex –Catheterized or midstream

Methods Standardized technique ( visual inspection ) by 2 independent observers –3 ml urine in red-topped blood tube –Held 1 cm from a white background with black printed 11-font text Cloudy –0.1 ml of 0.1 mol/L acetic acid solution to dissolve any phosphates If there was a discrepncy in determination of clarity between these 2 individuals, the specimen was considered cloudy.

Laboratory test Nitrates, leukocyte esterase (LE), bacteria and WBC Pyuria: ≥ 5 WBC/hpf Culture positive –Catheterized: ≥ 10 4 CFU/ml –Midstream: ≥10 5 CFU/ml Contamination: > 3 organisms

Exclusion Refered to the ED for evaluation of an abnormal U/A or positive U/C Currently on antibiotics Underlying medical problem requireing repeat catheterization,eg, neurogenic bladder Unable to obtain an adequate volume of urine Known to have an underlying renal and /or genitourinary abnormality

Results Patients samples 159 age : 4 weeks to 19 years ( mean: 5.8 years ) Sex : females-122(77%) / males-37(23%) collection : catheterization -70(44%) med-steam -89(56%) visual : clear- 110(69%) / cloudy-49(31%)

Results(2) Culture : (+)-29(18%)--- clear : 3 cloudy : 26 Culture : (-)-130(82%)--- clear : 107 cloudy : 23 finding : clear urine on visual inspection had a negative predictive value of 97%(107/110)

Results(3) 3 patients with clear urine who had a UTI (Table 2)--- 3 of patients <12months // WBC < patients 19-year // WBC >15 //abd. pain 3.D/U : (-) 4.Organism:E coli / K pneumoniae

Discussion(1) Up to 45% of children diagnosed with a will have a genitourinary abnormality requiring treatment. Many previous studies have examined the utility of urine dipsticks and microscopy in the rapid detection of UTIs in children. None of these tests have produced screening study with 100% sensitivity.

Discussion(2) Two studies 376 urine samples age: 6weeks to 17 years 85% MSU 13% bag specimens 2%suprapubic aspiration NPV for the absence of a UTI of 100%

Discussion(3) 500 urine samples age: 6 weeks to 18 years 57% MSU 42% bag specimens 1% catheterization UTI was diagnosed in 15 of these patients the others were considered contaminants.

Discussion(4) Limitations to this study First  using urine clarity as a screening tool requires accuracy in performing visual inspection. Second  it is a preliminary study attempting to define a method that may reveal the absence of significant bacteruria.

Conclusion Clear urine on visual inspection cannot completely eliminate the possibility that a child has a UTI. It is a reproducible test that offers the advantages of being simple, fast, and inexpensive. The finding of clear urine should be considered a reasonable and relatively effective bedside screen for the presence of a UTI.