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Localisation of UTI by laboratory tests

Bibliographic InformationStudy type & Evidence levelStudy AimsNumber of patients & prevalencePopulation CharacteristicsType of test and Reference standardSensitivity, Specificity, PPV and NPVReviewer comment
Pecile P;Miorin E;Romanello C;Falleti E;Valent F;Giacomuzzi F;Tenore A; 2004 Aug 185Study type: Diagnostic
Evidence level: II
To determine the accuracy of procalcitonin measurements in diagnosing acute renal involvement during febrile UTI and in predicting subsequent scars as assessed with DMSA.100 consecutive children (69 girls and 31 boys) admitted to a peaediatric department between Jan 2000 and Jan 2002 with first episode of febrile UTIChildren 1 months to 13 years (mean 19 months). 66 children were under 1 year.
Definition of UTI was positive culture with a single microorganism at ≥10^5cfu/ml from a catheterised or clean voided sample.
Patients with previously documented or suspected febrile UTIs were excluded
CRP levels, procalcitonin levels, ESR and leukocyte counts compared to DMSAClinical and Laboratory assessments
- body temperature
- duration of fever
- WBC count
- CRP level (values of ≥20mg/l were considered abnormal)
- ESR
- procalcitonin level (values of ≥0.8ng/ml were considered abnormal)
Imaging studies
- Ultrasound (performed within 3 days)
- VCUG (1 month after first infection to detect reflux)
- DMSA (5 days after admission). Score of 0 = absence of lesion, 1=uncertain or mild lesion, 2=mild lesion, 3=moderate lesion, 4=severe renal parenchymal lesion (covering >30% of surface area).
Study only showed diagnostic accuracy for the group of patients who scored 2–4 indicating acute pyelonephritis – more significant initial renal damage. The diagnostic accuracy for the group with mild renal damage is unknown. Additionally, only children who scored 2–4 were followed up.
Lin DS;Huang SH;Lin CC;Tung YC;Huang TT;Chiu NC;Koa HA;Hung HY;Hsu CH;Hsieh WS;Yang DI;Huang FY; 2000 Feb 186Study type: Diagnostic
Evidence level: III
To assess the usefulness of laboratory parameters including peripheral WBC count, CRP, ESR and microscopic urinalysis for identifying febrile infants younger than 8 weeks of age at risk of UTI.162 febrile children (94 boys, 68 girls)Febrile infants (rectal temperature >38°C) under 8 weeks old who presented to an emergency department between September 1997 and August 1998 and were hospitalised.
Exclusions: Infants who received antibiotics or had a SPA within 24 hours.
History and physical examination and a full evaluation for sepsis including peripheral WBC count, and differential ESR, CRP, blood culture, lumbar puncture, glucose level, protein level, Gram stain, urinalysis and culture.
All urine samples were collected by SPA.
All infants had negative blood and CSF cultures. 22/162 (13.6%) had positive urine cultures (4 girls, 18 boys).
Hemocytometer WBC counts (≥10 WBC/μl)
Sensitivity: 82%
Specificity: 94%
Accuracy: 92%
LR+: 12.7
LR−: 0.19
Standard UA (≥5 WBC/hpf)
Sensitivity: 59%
Specificity: 93%
Accuracy: 88%
LR+: 8.3
LR−: 0.44
CRP (>20 mg/L)
Sensitivity: 59%
Specificity: 90%
Accuracy: 86%
LR+: 5.9
LR−: 0.45
ESR (>30 mm/h)
Sensitivity: 73%
Specificity: 78%
Accuracy: 77%
LR+: 3.3
LR−: 0.35
Peripheral WBC (>15000/μl)
Sensitivity: 36%
Specificity: 80%
Accuracy: 74%
LR+: 1.8
LR−: 0.80
Benador N;Siegrist CA;Gendrel D;Greder C;Benador D;Assicot M;Bohuon C;Girardin E; 1998 Dec 187Study type: Diagnostic
Evidence level: III
To measure PCT levels in children with febrile UTI, to compare it to other inflammatory markers and to evaluate it’s ability to predict renal involvement as assessed by DMSA.60 children (17 boys, 43 girls)Children 1 month to 16 years old (mean age lower UTI 36 months, mean age pyelonephritis 42 months) diagnosed with clinical signs of acute pyelonephritis.
Acute pyelonephritis defined as rectal temperature ≥38°C and abdominal pain in older children, or non-specific signs in younger children such as irritability or vomiting.
Confirmation by positive urine culture where ≥104cfu/ml for midstream clean voided urine, ≥103 for SPA or catheterisation.
Test: Blood samples were collected on admission for determination of PCT, CRP and leukocyte counts
Tests were considered abnormal at:
PCT >0.6μg/L
CRP >10mg/L
DMSA was performed within 5 days of admission. Lesions were graded in 5 categories:
0 – absence of lesion (lower UTI)
1 – very mild (defect covering<5% surface area)
2 – mile (defect covering 5% –10% surface area)
3 – moderate (defect covering 10% –30% surface area)
4 – severe renal parenchymal lesions (defect covering >30% surface area)
Age (months) – 36 ± 9 vs. 42 ± 8, p=0.350
Sex (female/male) – 14/9 vs. 29/8, p=0.140
Leukocyte count (mm3)– 10939 ± 834 vs. 17429 ± 994, p=0.0001
PCT (μg/L) – 0.38 ± 0.19 vs. 5.37 ± 1.9, p<0.0001
CRP (mg/L) – 30.3 ± 7.6 vs. 120.8 ± 8.9, p<0.0001
When inflammatory markers were correlated with severity of renal lesions ranked by DMSA, PCT was significantly correlated (p<0.0001) however CRP was of borderline significance (p=0.032).
CRP
Sensitivity: 100%
Specificity 26.1%
PCT
Sensitivity: 70.3%
Specificity: 82.6%
Gurgoze MK;Akarsu S;Yilmaz E;Godekmerdan A;Akca Z;Ciftci I;Aygun AD; 2005 188Study type: Diagnostic
Evidence level: III−
Compared serum levels of proinflammatory cytokines and procalcitonin in children with acute pyelonephritis and with lower tract UTI to establish whether they could be used as a marker in distinguishing acute pyelonephritis.76 children (48 girls, 28 boys)Children aged 2 to 144 months (mean age 39.6 ± 33.8 months).
All children had been diagnosed with UTI by clinical findings (fever, nausea/vomiting, appetite, dysuria, nonspecific abdominal pain) and laboratory analysis (10^5cfu/ml midstream sample or 10^3cfu/ml in a catheterised sample).
Test: Blood sample (before initiating antibiotic treatment)
DMSA
Reference test:
34 children (20 girls and 14 boys) had acute pyelonephtritis (mean age 43.4 months) and 42 children (28 girls and 14 boys) had lower UTI (mean age 34.6 months).
PCT (at 0.5ng/ml)
Sensitivity 58%
Specificity 76%
CRP (at 20mg/l
Sensitivity 94%
Specificity 58%
IL-ß1 (at 6.9pg/ml)
Sensitivity 97%
Specificity 59%
IL-6 (at 18pg/ml)
Sensitivity 88%
Specificity 74%
TNF-a (at 2.2pg/ml)
Sensitivity 88%
Specificity 80%
Study did not provide numbers so no sensitivities/specificitie s could be checked.
Evidence level - so should be excluded if other quality studies are found.
Smolkin V;Koren A;Raz R;Colodner R;Sakran W;Halevy R; 2002 189Study type: Diagnostic
Evidence level: III−
To evaluate the ability of PCT level to predict renal involvement assessed by DMSA.64 children (44 girls and 20 boys)Children aged 2 weeks to 3 years (mean 16.7 ± 8.6 months) admitted to a paediatric department with febrile UTI. Inclusion was confirmed by a positive urine culture.
Positive urine culture was defined as any growth on SPA and 10^3cfu/ml on catheterisation.
Test:
Reference test: CRP and PCT (on admission) compared to DMSA (performed within 7 days of admission)
PCT where a value of >0.5ug/l was considered abnormal
CRP where a value of >20mg/l was considered abnormal.
DMSA where renal pathology was defined as focal or multifocal perfusion defects or as split renal uptake of less than 45%.
CRP at a cut off value of 20mg/l
Sensitivity 100%
Specificity 18.5%
PPV100%
NPV 30.9%
PCT at a cut off value of 0.5ug/l
Sensitivity 94.1%
Specificity 89.7%
PPV 97.6%
NPV 85.7%
The median PCT level was significantly higher in the acute pyelonephritis group (3.41, range 0.36 to 12.4) than the lower UTI group (0.13 range 0.02 to 2.15) p<0.0001.
Study did not provide numbers so no sensitivities/specificitie s could be checked.
Evidence level - so should be excluded if other quality studies are found.

From: Evidence tables

Cover of Urinary Tract Infection in Children
Urinary Tract Infection in Children: Diagnosis, Treatment and Long-term Management.
NICE Clinical Guidelines, No. 54.
National Collaborating Centre for Women's and Children's Health (UK).
London: RCOG Press; 2007 Aug.
Copyright © 2007, National Collaborating Centre for Women’s and Children’s Health.

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