Receiver Operating Characteristic (ROC) Curves: The Basics and Beyond.

Diagnostic tests and clinical prediction rules are frequently used to help estimate the probability of a disease or outcome. How well a test or rule distinguishes between disease or no disease (discrimination) can be measured by plotting a receiver operating characteristic (ROC) curve and calculating the area under it (AUROC). In this paper, we review the features of ROC curves and interpretation of ROC curves and AUROC values. We highlight 5 underappreciated features of ROC curves: (1) the slope of the ROC curve over a test result interval is the likelihood ratio for that interval; (2) the optimal cutoff for calling a test positive depends not only on the shape of the ROC curve, but also on the pretest probability of disease and relative harms of false-positive and false-negative results; (3) the AUROC measures discrimination only, not the accuracy of the predicted probabilities; (4) the AUROC is not a good measure of discrimination if the slope of the ROC curve is not consistently decreasing; and (5) the AUROC can be increased by including a large number of people correctly identified as being at very low risk for the outcome of interest. We illustrate this last concept using 3 published studies.

Reducing IV Antibiotic Duration for Neonatal UTI Using a Clinical Standard Pathway.

OBJECTIVES: Urinary tract infections (UTIs) are the most common bacterial infections in young infants and are traditionally treated with longer intravenous (IV) antibiotic courses. A growing body of evidence supports shorter IV antibiotic courses for young infants. Our primary aim was to decrease the IV antibiotic treatment to 3 days over 2 years for neonates aged 0 to 28 days who have been hospitalized with UTIs. METHODS: Using quality improvement methods, our primary intervention was to implement a revised clinical pathway recommending 3 (previously 7) days of IV antibiotics. Our primary outcome measure was IV antibiotic duration, and the secondary outcomes were length of stay (LOS) and costs. The balancing measure was readmission within 30 days of discharge. Neonates were identified by using International Classification of Diseases diagnosis codes and excluded if they were admitted to the ICU or had a LOS >30 days. We used statistical process control to analyze outcome measures for 4 years before (baseline) and 2 years after the pathway revision (intervention) in February 2020. RESULTS: A total of 93 neonates were hospitalized with UTIs in the baseline period and 41 were hospitalized in the intervention period. We found special cause variation, with a significant decrease in mean IV antibiotic duration from 4.7 (baseline) to 3.1 days (intervention) and a decrease in mean LOS from 5.4 to 3.6 days. Costs did not differ between the baseline and intervention periods. There were 7 readmissions during the baseline period, and 0 during the intervention period. CONCLUSIONS: The implementation of a revised clinical pathway significantly reduced IV antibiotic treatment duration and hospital LOS for neonatal UTIs without an increase in hospital readmissions.

Frequency of Treatment Failure of UTIs in Children With Congenital Urinary Tract Anomalies.

OBJECTIVES: Children with certain congenital anomalies of the kidney and urinary tract and neurogenic bladder (CAKUT/NGB) are at higher risk of treatment failure for urinary tract infections (UTIs) than children with normal genitourinary anatomy, but the literature describing treatment and outcomes is limited. The objectives of this study were to describe the rate of treatment failure in children with CAKUT/NGB and compare duration of antibiotics between those with and without treatment failure. METHODS: Multicenter retrospective cohort of children 0 to 17 years old with CAKUT/NGB who presented to the emergency department with fever or hypothermia and were diagnosed with UTI between 2017 and 2018. The outcome of interest was treatment failure, defined as subsequent emergency department visit or hospitalization for UTI because of the same pathogen within 30 days of the index encounter. Descriptive statistics and univariates analyses were used to compare covariates between groups. RESULTS: Of the 2014 patient encounters identified, 482 were included. Twenty-nine (6.0%) of the 482 included encounters had treatment failure. There was no difference in the mean duration of intravenous antibiotics (3.4 ± 2.5 days, 3.5 ± 2.8 days, P = .87) or total antibiotics between children with and without treatment failure (10.2 ± 3.8 days, 10.8 ± 4.0 days, P = .39) Of note, there was a higher rate of bacteremia in children with treatment failure (P = .04). CONCLUSIONS: In children with CAKUT/NGB and UTI, 6.0% of encounters had treatment failure. Duration of antibiotics was not associated with treatment failure. Larger studies are needed to assess whether bacteremia modifies the risk of treatment failure.

Marijuana Use and Breastfeeding: A Survey of Newborn Nurseries.

BACKGROUND AND OBJECTIVES: Marijuana use has increased nationally and is the most common federally illicit substance used during pregnancy. This study aimed to describe hospital practices and nursery director knowledge and attitudes regarding marijuana use and breastfeeding and assess the association between breastfeeding restrictions and provider knowledge, geographic region, and state marijuana legalization status. We hypothesized that there would be associations between geography and/or state legalization and hospital practices regarding breastfeeding with perinatal marijuana use. METHODS: A cross-sectional, 31-question survey was sent electronically to the 110 US hospital members of the Academic Pediatric Association's Better Outcomes through Research for Newborns (BORN) network. Survey responses were analyzed using descriptive statistics to report frequencies. For comparisons, χ2 and Fisher exact tests were used to determine statistical significance. RESULTS: Sixty-nine (63%) BORN nursery directors across 38 states completed the survey. For mothers with a positive cannabinoid screen at delivery, 16% of hospitals universally or selectively restrict breastfeeding. Most (96%) nursery directors reported that marijuana use while breastfeeding is "somewhat" (70%) or "very harmful" (26%). The majority was aware of the potential negative impact of prenatal marijuana use on learning and behavior. There were no consistent statistical associations between breastfeeding restrictions and provider marijuana knowledge, geographic region, or state marijuana legalization status. CONCLUSIONS: BORN newborn clinicians report highly variable and unpredictable breastfeeding support practices for mothers with perinatal marijuana use. Further studies are needed to establish evidence-based practices and to promote consistent, equitable care of newborns with perinatal marijuana exposure.

Effect Modifiers of the Association of High-Flow Nasal Cannula and Bronchiolitis Length of Stay.

BACKGROUND AND OBJECTIVES: High-flow nasal cannula (HFNC) therapy for hospitalized children with bronchiolitis is associated with a longer length of stay (LOS) when used outside of the ICU. We sought to explore the association between HFNC and LOS to identify if demographic and clinical factors may modify the effect of HFNC usage on LOS. METHODS: In this multicenter retrospective cohort study, we used a combination of hospital records and the Pediatric Health Information System. We included encounters from September 1, 2018 to March 31, 2020 for patients <2 years old diagnosed with bronchiolitis. Multivariable Poisson regression was performed for the association of LOS with measured covariates, including fixed main effects and interaction terms between HFNC and other factors. RESULTS: Of 8060 included patients, 2179 (27.0%) received HFNC during admission. Age group, weight, complex chronic condition, initial tachypnea, initial desaturation, and ICU services were significantly associated with LOS. The effect of HFNC on LOS differed among hospitals (P < .001), with the estimated increase in LOS ranging from 32% to 139%. The effect of HFNC on LOS was modified by age group, initial desaturation, and ICU services, with 1- to 6-month-old infants, patients without initial desaturation, and patients without ICU services having the highest association between HFNC and LOS, respectively. CONCLUSIONS: We identified multiple potential effect modifiers for the relationship between HFNC and LOS. The authors of future prospective studies should investigate the effect of HFNC usage on LOS in non-ICU patients without documented desaturation.

Perspectives of Health Care Personnel on the Benefits of Bronchiolitis Interventions.

OBJECTIVES: Many interventions in bronchiolitis are low-value or poorly studied. Inpatient bronchiolitis management is multidisciplinary, with varying degrees of registered nurse (RN) and respiratory therapist (RT) autonomy. Understanding the perceived benefit of interventions for frontline health care personnel may facilitate deimplementation efforts. Our objective was to examine perceptions surrounding the benefit of common inpatient bronchiolitis interventions. METHODS: We conducted a cross-sectional survey of inpatient pediatric RNs, RTs, and physicians/licensed practitioners (P/LPs) (eg, advanced-practice practitioners) from May to December of 2021 at 9 university-affiliated and 2 community hospitals. A clinical vignette preceded a series of inpatient bronchiolitis management questions. RESULTS: A total of 331 surveys were analyzed with a completion rate of 71.9%: 76.5% for RNs, 57.4% for RTs, and 71.2% for P/LPs. Approximately 54% of RNs and 45% of RTs compared with 2% of P/LPs believe albuterol would be "extremely or somewhat likely" to improve work of breathing (P < .001). Similarly, 52% of RNs, 32% of RTs, and 23% of P/LPs thought initiating or escalating oxygen in the absence of hypoxemia was likely to improve work of breathing (P < .001). Similar differences in perceived benefit were observed for steroids, nebulized hypertonic saline, and deep suctioning, but not superficial nasal suctioning. Hospital type (community versus university-affiliated) did not impact the magnitude of these differences. CONCLUSIONS: Variation exists in the perceived benefit of several low-value or poorly studied bronchiolitis interventions among health care personnel, with RNs/RTs generally perceiving higher benefit. Deimplementation, educational, and quality improvement efforts should be designed with an interprofessional framework.

The Effect of Readmission for Phototherapy on Early Breast Milk Feeding.

OBJECTIVES: To estimate the effect of readmission for inpatient phototherapy on parent-reported exclusive and any breast milk feeding at 2-month well-child visits. METHODS: We performed a retrospective cohort study using electronic health record data. From births at 16 Kaiser Permanente Northern California hospitals (2013-2017), we identified a cohort of infants ≥35 weeks' gestation with outpatient total serum bilirubin levels ranging from 1 mg/dL below to 2.9 mg/dL above the American Academy of Pediatrics phototherapy threshold at <15 days of age. We compared breast milk feeding at 2-month well-child visits among those readmitted and not readmitted to the hospital for phototherapy, adjusting for bilirubin and other confounding variables. RESULTS: Approximately one-quarter (26.5%) of the cohort (n = 7729) were readmitted for phototherapy. Almost half (48.5%) of the infants who were not readmitted for phototherapy received exclusively breast milk at the 2-month visit compared with slightly fewer infants who were readmitted (42.9%). In both groups of infants, most (82.2% not readmitted and 81.2% readmitted) received any breast milk. Readmission for phototherapy was associated with a lower adjusted risk of exclusive breast milk feeding (adjusted risk ratio 0.90; 95% confidence interval [CI], 0.84 to 0.96), corresponding to a marginal absolute reduction in exclusive breast milk feeding of 5.0% (95% CI, -7.9% to -2.1%). It was not associated with a reduction in any breast milk feeding (adjusted risk ratio, 1.00; 95% CI, 0.97 to 1.02). CONCLUSIONS: Infants readmitted for phototherapy were more likely to receive any formula, but no less likely to receive any breast milk at 2-month well-child visits.

Impact of Diagnostic Criteria on UTI Prevalence in Young Infants With Jaundice: A Meta-analysis.

BACKGROUND AND OBJECTIVE: Previously reported prevalence of urinary tract infections (UTIs) in infants with jaundice range from <1% to 25%. However, UTI criteria are variable and, as demonstrated in a meta-analysis on UTI prevalence in bronchiolitis, disease prevalence is greatly impacted by disease definition. The objective of this study was to conduct a systemic review and meta-analysis examining the impact of including positive urinalysis (UA) results as a diagnostic criterion on the estimated UTI prevalence in young infants with jaundice. METHODS: The data sources used were Medline (1946-2020) and Ovid Embase (1976-2020) through January 2020 and bibliographies of retrieved articles. We selected studies reporting UTI prevalence in young infants with jaundice. Data were extracted in accordance with meta-analysis of observational studies in epidemiology guidelines. Random-effects models produced a weighted pooled event rate with 95% confidence intervals (CI). RESULTS: We screened 526 unique articles by abstract and reviewed 53 full-text articles. We included 32 studies and 16 contained UA data. The overall UTI prevalence in young infants with jaundice from all 32 studies was 6.2% (95% CI, 3.9-8.9). From the 16 studies with UA data, the overall UTI prevalence was 8.7% (95% CI, 5.1-13.2), which decreased to 3.6% (95% CI, 2.0-5.8) with positive UA results included as a diagnostic criterion. CONCLUSIONS: The estimated UTI prevalence in young infants with jaundice decreases substantially when UA results are incorporated into the UTI definition. Due to the heterogeneity of study subjects' ages and definitions of jaundice, positive UA results, and UTI, there is uncertainty about the exact prevalence and about which infants with hyperbilirubinemia warrant urine testing.

The effect of hospital phototherapy on early breastmilk feeding.

BACKGROUND: The effect of phototherapy on breastmilk feeding is unclear. OBJECTIVE: To estimate the effect of inpatient phototherapy on breastmilk feeding at 2-month well-child visits. METHODS: We performed a retrospective cohort study using electronic health record data. From births at 16 Kaiser Permanente Northern California hospitals (2013-2017), we identified a cohort of infants ≥ 35 weeks' gestation with total serum bilirubin levels close to the American Academy of Pediatrics 2004 phototherapy threshold during their birth hospitalisation. We compared self-reported breastmilk feeding at 2-month well-child visits among those who had and had not received birth hospitalisation phototherapy, adjusting for bilirubin levels and other confounding variables. We used multiple imputation (K = 200) to address missing data. RESULTS: Approximately a quarter of infants in the cohort (24.5%) received phototherapy during their birth hospitalisation. At the 2-month visit, exclusive breastmilk feeding was less common (RR 0.91, 95% interval [CI] 0.88, 0.95) among those who received phototherapy (41.3%) than those who did not (45.2%). However, no association remained after adjusting for potential confounders (RR 0.99, 95% CI 0.95, 1.04; average treatment effect on the treated [ATET] -0.2%, 95% CI -2.0%, 1.5%). In contrast, any breastmilk feeding was similar between infants who did (76.8%) and did not get phototherapy (77.9%). After adjusting for confounders, phototherapy had a slightly positive association with any breastmilk feeding at 2 months (RR 1.02, 95% CI 1.00, 1.04). Among infants who received phototherapy, the proportion being fed any breastmilk at the 2-month visit was an estimated 1.6 percentage points higher than it would have been if they had not received phototherapy (ATET 1.6%, 95% CI 0.1%, 3.1%). Multiple imputation results were similar. CONCLUSIONS: Birth hospitalisation phototherapy can be delivered in a way that does not adversely affect breastmilk feeding at 2 months.

Diagnosis and Management of UTI in Febrile Infants Age 0-2 Months: Applicability of the AAP Guideline.

Urinary tract infections (UTIs) are the most common bacterial infection in young infants. The American Academy of Pediatrics' (AAP) clinical practice guideline for UTIs focuses on febrile children age 2-24 months, with no guideline for infants <2 months of age, an age group commonly encountered by pediatric hospitalists. In this review, we assess the applicability of the AAP UTI Guideline's action statements for previously healthy, febrile infants <2 months of age. We also discuss additional considerations in this age group, including concurrent bacteremia and routine testing for meningitis.

Evaluation of Home Phototherapy for Neonatal Hyperbilirubinemia.

OBJECTIVE: To characterize home phototherapy treatment for neonatal hyperbilirubinemia and assess the risk factors associated with the need for hospital admission during or after home phototherapy. STUDY DESIGN: This was a retrospective study of newborn infants born at ≥35 weeks of gestation who underwent comprehensive home phototherapy (that included daily in-home lactation support and blood draws) over an 18-month period. We excluded infants who lacked a recorded birth date or time, started treatment at age >14 days, or had a conjugated serum bilirubin level of ≥2 mg/dL (≥34.2 µmol/L). The primary study outcome was any hospital admission during or within 24 hours after completion of home phototherapy. Logistic regression was used to identify risk factors for hospitalization. RESULTS: Of the cohort of 1385 infants, 1324 met the inclusion criteria. At the time home phototherapy was initiated, 376 infants (28%) were at or above the American Academy of Pediatrics phototherapy threshold. Twenty-five infants required hospitalization (1.9%; 95% CI, 1.3%-2.8%). Hospital admission was associated with a younger age at phototherapy initiation (OR, 0.63 for each day older in age; 95% CI, 0.44-0.91) and a higher total serum bilirubin level relative to the treatment threshold at phototherapy initiation (OR, 1.71 for each 1 mg/dL above the treatment threshold; 95% CI, 1.40-2.08). CONCLUSIONS: Comprehensive home phototherapy successfully treated hyperbilirubinemia in the vast majority of the infants in this cohort.

A Simpler Prediction Rule for Rebound Hyperbilirubinemia.

OBJECTIVES: We previously reported a clinical prediction rule to estimate the probability of rebound hyperbilirubinemia using gestational age (GA), age at phototherapy initiation, and total serum bilirubin (TSB) relative to the treatment threshold at phototherapy termination. We investigated (1) how a simpler 2-variable model would perform and (2) the absolute rebound risk if phototherapy were stopped at 2 mg/dL below the threshold for treatment initiation. METHODS: Subjects for this retrospective cohort study were infants born 2012-2014 at ≥35 weeks' gestation at 1 of 17 Kaiser Permanente hospitals who underwent inpatient phototherapy before age 14 days. TSB reaching the phototherapy threshold within 72 hours of phototherapy termination was considered rebound. We simplified by using the difference between the TSB level at the time of phototherapy termination and the treatment threshold at the time of phototherapy initiation as 1 predictor, and kept GA as the other predictor. RESULTS: Of the 7048 infants treated with phototherapy, 4.6% had rebound hyperbilirubinemia. The area under the receiver operating characteristic curve was 0.876 (95% confidence interval, 0.854 to 0.899) for the 2-variable model versus 0.881 (95% confidence interval, 0.859 to 0.903) for the 3-variable model. The rebound probability after stopping phototherapy at 2 mg/dL below the starting threshold was 2.5% for infants ≥38 weeks' GA and 10.2% for infants <38 weeks' GA. CONCLUSIONS: Rebound hyperbilirubinemia can be predicted by a simpler 2-variable model consisting of GA and the starting threshold-ending TSB difference. Infants <38 weeks' gestation may need longer phototherapy because of their higher rebound risk.

A Clinical Prediction Rule for Rebound Hyperbilirubinemia Following Inpatient Phototherapy.

OBJECTIVES: The American Academy of Pediatrics provides little guidance on when to discontinue phototherapy in newborns treated for hyperbilirubinemia. We sought to develop a prediction rule to estimate the probability of rebound hyperbilirubinemia after inpatient phototherapy. METHODS: Subjects for this retrospective cohort study were infants born in 2012 to 2014 at ≥35 weeks' gestation at 16 Kaiser Permanente Northern California hospitals who received inpatient phototherapy before age 14 days. We defined rebound as the return of total serum bilirubin (TSB) to phototherapy threshold within 72 hours of phototherapy termination. We used stepwise logistic regression to select predictors of rebound hyperbilirubinemia and devised and validated a prediction score by using split sample validation. RESULTS: Of the 7048 infants treated with inpatient phototherapy, 4.6% had rebound hyperbilirubinemia. Our prediction score consisted of 3 variables: gestational age <38 weeks (adjusted odds ratio [aOR] 4.7; 95% confidence interval [CI], 3.0-7.3), younger age at phototherapy initiation (aOR 0.51 per day; 95% CI, 0.38-0.68), and TSB relative to the treatment threshold at phototherapy termination (aOR 1.5 per mg/dL; 95% CI, 1.4-1.7). The model performed well with an area under the receiver operating characteristic curve of 0.89 (95% CI, 0.86-0.91) in the derivation data set and 0.88 (95% CI, 0.86-0.90) in the validation data set. Approximately 70% of infants had scores <20, which correspond to a <4% probability of rebound hyperbilirubinemia. CONCLUSIONS: The risk of rebound hyperbilirubinemia can be quantified according to an infant's gestational age, age at phototherapy initiation, and TSB relative to the treatment threshold at phototherapy termination.

Update on Predicting Severe Hyperbilirubinemia and Bilirubin Neurotoxicity Risks in Neonates.

Extreme hyperbilirubinemia and kernicterus, though rare, continue to occur despite the adoption of universal screening. Unless they are known to have glucose-6-phosphate dehydrogenase deficiency, infants who currently develop kernicterus in high resource countries are often otherwise healthy newborns discharged from the well-baby nursery. In this review, we highlight risk factors that increase the risk of a newborn ≥35 weeks gestational age developing severe hyperbilirubinemia, as well as the risk factors that increase the hyperbilirubinemic infant's risk of kernicterus.

Urinary Imaging Findings in Young Infants With Bacteremic Urinary Tract Infection.

OBJECTIVES: To describe renal ultrasound (RUS) and voiding cystourethrogram (VCUG) findings and determine predictors of abnormal imaging in young infants with bacteremic urinary tract infection (UTI). METHODS: We used retrospective data from a multicenter sample of infants younger than 3 months with bacteremic UTI, defined as the same pathogenic organism in blood and urine. Infants were excluded if they had any major comorbidities, known urologic abnormalities at time of presentation, required intensive unit care, or had no imaging performed. Imaging results as stated in the radiology reports were categorized by a pediatric urologist. RESULTS: Of the 276 infants, 19 were excluded. Of the remaining 257 infants, 254 underwent a RUS and 224 underwent a VCUG. Fifty-five percent had ≥1 RUS abnormalities. Thirty-four percent had ≥1 VCUG abnormalities, including vesicoureteral reflux (VUR, 27%), duplication (1.3%), and infravesicular abnormality (0.9%). Age <1 month, male sex, and non-Escherichia coli organism predicted an abnormal RUS, but only non-E coli organism predicted an abnormal VCUG. Seventeen of 96 infants (17.7%) with a normal RUS had an abnormal VCUG: 15 with VUR (Grade I-III = 13, Grade IV = 2), 2 with elevated postvoid residual, and 1 with infravesical abnormality. CONCLUSIONS: Although RUS and VCUG abnormalities were common in this cohort, the frequency and severity were similar to previous studies of infants with UTIs in general. Our findings do not support special consideration of bacteremia in imaging decisions for otherwise well-appearing young infants with UTI.

Bacteraemic urinary tract infection: management and outcomes in young infants.

OBJECTIVES: To determine predictors of parenteral antibiotic duration and the association between parenteral treatment duration and relapses in infants <3 months with bacteraemic urinary tract infection (UTI). DESIGN: Multicentre retrospective cohort study. SETTING: Eleven healthcare institutions across the USA. PATIENTS: Infants <3 months of age with bacteraemic UTI, defined as the same pathogenic organism isolated from blood and urine. MAIN OUTCOME MEASURES: Duration of parenteral antibiotic therapy, relapsed UTI within 30 days. RESULTS: The mean (±SD) duration of parenteral antibiotics for the 251 included infants was 7.8 days (±4 days), with considerable variability between institutions (mean range 5.5-12 days). Independent predictors of the duration of parenteral antibiotic therapy included (coefficient, 95% CI): age (-0.2 days, -0.3 days to -0.08 days, for each week older), year treated (-0.2 days, -0.4 to -0.03 days for each subsequent calendar year), male gender (0.9 days, 0.01 to 1.8 days), a positive repeat blood culture during acute treatment (3.5 days, 1.2-5.9 days) and a non-Escherichia coli organism (2.2 days, 0.8-3.6 days). No infants had a relapsed bacteraemic UTI. Six infants (2.4%) had a relapsed UTI (without bacteraemia). The duration of parenteral antibiotics did not differ between infants with and without a relapse (8.2 vs 7.8 days, p=0.81). CONCLUSIONS: Parenteral antibiotic treatment duration in young infants with bacteraemic UTI was variable and only minimally explained by measurable patient factors. Relapses were rare and were not associated with treatment duration. Shorter parenteral courses may be appropriate in some infants.

Diagnostic accuracy of the urinalysis for urinary tract infection in infants <3 months of age.

BACKGROUND: The 2011 American Academy of Pediatrics urinary tract infection (UTI) guideline suggests incorporation of a positive urinalysis (UA) into the definition of UTI. However, concerns linger over UA sensitivity in young infants. Infants with the same pathogenic organism in the blood and urine (bacteremic UTI) have true infections and represent a desirable population for examination of UA sensitivity. METHODS: We collected UA results on a cross-sectional sample of 276 infants <3 months of age with bacteremic UTI from 11 hospital systems. Sensitivity was calculated on infants who had at least a partial UA performed and had ≥50 000 colony-forming units per milliliter from the urine culture. Specificity was determined by using a random sample of infants from the central study site with negative urine cultures. RESULTS: The final sample included 245 infants with bacteremic UTI and 115 infants with negative urine cultures. The sensitivity of leukocyte esterase was 97.6% (95% confidence interval [CI] 94.5%-99.2%) and of pyuria (>3 white blood cells/high-power field) was 96% (95% CI 92.5%-98.1%). Only 1 infant with bacteremic UTI (Group B Streptococcus) and a complete UA had an entirely negative UA. In infants with negative urine cultures, leukocyte esterase specificity was 93.9% (95% CI 87.9 - 97.5) and of pyuria was 91.3% (84.6%-95.6%). CONCLUSIONS: In young infants with bacteremic UTI, UA sensitivity is higher than previous reports in infants with UTI in general. This finding can be explained by spectrum bias or by inclusion of faulty gold standards (contaminants or asymptomatic bacteriuria) in previous studies.