Urine Specific Gravity and the Accuracy of Urinalysis

Localized Surface Plasmon Resonance Sensing and its Interplay with Fluidics

In this Feature Article, we discuss the interplay between fluidics and the localized surface plasmon resonance (LSPR) sensing technique, primarily focusing on its applications in the realm of bio/chemical sensing within fluidic environments. Commencing with a foundational overview of LSPR principles from a sensing perspective, we subsequently showcase the development of a streamlined LSPR chip integrated with microfluidic structures. This integration opens the doors to advanced experiments involving fluid dynamics, greatly expanding the scope of LSPR-based research. Our discussions then turn to the practical implementation of LSPR and microfluidics in real-time biosensing, with a specific emphasis on monitoring DNA polymerase activity. Additionally, we illustrate the direct sensing of biological fluids, exemplified by the analysis of urine, while also shedding light on a unique particle assembly process that occurs on LSPR chips. We not only discuss the significance of LSPR sensing but also explore its potential to investigate a plethora of phenomena at liquid-liquid and solid-liquid interfaces. This is particularly noteworthy, as existing transduction methods and sensors fall short in fully comprehending these interfacial phenomena. Concluding our discussion, we present a futuristic perspective that provides insights into potential opportunities emerging at the intersection of fluidics and LSPR sensing.

Antibiotic Stewardship and Treatment of Uncomplicated Urinary Tract Infection (UTI) in Children and Adolescents in the Emergency Department of a Community Hospital

A retrospective, cross-sectional study of children with suspected urinary tract infections (UTIs) 3 months to 18 years of age who had a urinalysis and urine culture (UC) during an emergency department (ED) visit between 2019 and 2020 was performed. Chi-square, Fisher exact, and independent samples T tests were used as appropriate. Median age was 6.6 years (interquartile range = 3.3-12.4). Urinalysis positivity was 92.8%, of which 81.9% of children were prescribed a first-line antibiotic. First-line antibiotic use was 82.7%. Positive UC rate was 84.7%, with 84% receiving a first-line antibiotic (P = .025). The correlation between a positive urinalysis and a positive UC was 80.8% (P < .001). Change of antibiotics based on the uropathogen of positive UCs was 6.3% (P < .001). The urinalysis and UC guided the diagnosis and treatment of UTIs. First-line antibiotics can be safely administered in the ED and prescribed for positive urinalyses. Studies are needed to evaluate the discontinuation of antibiotics with negative UCs as part of antibiotic stewardship initiatives.

Urine specific gravity, pyuria, and neutrophil gelatinase-associated lipocalin for identifying urinary tract infection in young children

BACKGROUND

To determine whether urine neutrophil gelatinase-associated lipocalin (uNGAL) might be superior to pyuria for detecting urinary tract infection (UTI) regardless of urine specific gravity (SG) in young children.

METHODS

We conducted a retrospective analysis of children aged < 3 years who were evaluated for UTI with urinalysis, urine culture, and uNGAL measurements during a 5-year period. Sensitivity, specificity, likelihood ratios (LRs), predictive values (PVs), area under the curves (AUCs) of uNGAL cut-off levels, and various microscopic pyuria thresholds for detecting UTI were calculated for dilute (SG < 1.015) and concentrated urine (SG ≥ 1.015).

RESULTS

Of 456 children included, 218 had UTI. The diagnostic value of urine white blood cell (WBC) concentration to define UTI changed with urine SG. For detecting UTI, uNGAL cut-off of 68.4 ng/mL had higher AUC values than pyuria ≥ 5 WBCs/high power field (HPF) for dilute and concentrated urine samples (both P < 0.05). Positive LR and PV and specificity of uNGAL were all greater than those of pyuria ≥ 5 WBCs/HPF regardless of urine SG, although the sensitivity of pyuria ≥ 5 WBCs/HPF was higher than that of uNGAL cut-off for dilute urine (93.8% vs. 83.5%) (P < 0.05). At uNGAL ≥ 68.4 ng/mL and ≥ 5 WBCs/HPF, posttest probabilities of UTI were 68.8% and 57.5% for dilute urine and 73.4% and 57.3% for concentrated urine, respectively.

CONCLUSIONS

Urine SG can affect the diagnostic performance of pyuria for detecting UTI and uNGAL might be helpful for identifying UTI regardless of urine SG in young children. A higher resolution version of the Graphical abstract is available as Supplementary information.

Management of antibacterial therapy of infectious and inflammatory diseases of the urinary tract in children and regional peculiarities during the COVID-19 pandemic

Urinary tract infections (UTIs) remain an urgent issue in clinical pediatrics. Empirical selection of antibacterial therapy becomes more complicated, and antibacterial drug indication is not always clinically substantiated. This study aimed to compare the antibacterial susceptibility pattern of the main group of urinary tract infectious agents from 2009–2016 with intermediate results from 2020–2021, during the COVID-19 pandemic, among children in the Chernivtsi region. Urine samples were collected from 3089 children (0–17 years old) treated at the health care institutions in the Chernivtsi region (2009–2016). The clinical-laboratory examination of 177 children (0–17 years old) was carried out from 2020 to 2021. The children received specialized medical care at the Department of Nephrology. Preliminary data of regional monitoring (2020–2021) are not considerably different from the previous regional susceptibility of antibiotics: to penicillin (p<0.01), ІІ-ІІІ generation cephalosporin (p<0.01); an increased resistance to levofloxacin (χ²=4,338; p<0.01), tetracycline – χ²=7,277; p<0.01; doxycycline – χ²=5,309; p<0.01) and imipenem – χ²=5,594; p<0.01). The data obtained did not explain an increased resistance to fluoroquinolones completely (ofloxacin, pefloxacin, ciprofloxacin), except for levofloxacin (χ²=4,338; p<0.01). A reliable difference of susceptibility of tetracycline group was registered (tetracycline – χ²=7,277; p<0.01; doxycycline – χ²=5,309; p<0.01). Furthermore, there was a regional increase in some UTI-pathogen strains resistant to carbapenems (imipenem – χ²=5,594; p<0.01). The use of antibiotics from the group of penicillins and II-III generation cephalosporins as the starting antibacterial therapy for STIs during the COVID-19 pandemic should be justified. A regional increase (2020–2021) of some uropathogenic strains resistant to carbapenems administered to treat severe bacterial infections requires their exclusively designated purpose in everyday pediatric practical work.

Diagnostic value of biomarkers for paediatric urinary tract infections in primary care: systematic review and meta-analysis

Background

Accurate diagnosis of urinary tract infection is essential as children left untreated may suffer permanent renal injury.

Aim

To compare the diagnostic values of biomarkers or clinical prediction rules for urinary tract infections in children presenting to ambulatory care.

Design and setting

Systematic review and meta-analysis of ambulatory care studies.

Methods

Medline, Embase, WOS, CINAHL, Cochrane library, HTA and DARE were searched until 21 May 2021. We included diagnostic studies on urine or blood biomarkers for cystitis or pyelonephritis in children below 18 years of age. We calculated sensitivity, specificity and likelihood ratios. Data were pooled using a bivariate random effects model and a Hierarchical Summary Receiver Operating Characteristic analysis.

Results

Seventy-five moderate to high quality studies were included in this review and 54 articles in the meta-analyses. The area under the receiver-operating-characteristics curve to diagnose cystitis was 0.75 (95%CI 0.62 to 0.83, n = 9) for C-reactive protein, 0.71 (95% CI 0.62 to 0.80, n = 4) for procalcitonin, 0.93 (95% CI 0.91 to 0.96, n = 22) for the dipstick test (nitrite or leukocyte esterase ≥trace), 0.94 (95% CI 0.58 to 0.98, n = 9) for urine white blood cells and 0.98 (95% CI 0.92 to 0.99, n = 12) for Gram-stained bacteria. For pyelonephritis, C-reactive protein < 20 mg/l had LR- of 0.10 (95%CI 0.04–0.30) to 0.22 (95%CI 0.09–0.54) in children with signs suggestive of urinary tract infection.

Conclusions

Clinical prediction rules including the dipstick test biomarkers can support family physicians while awaiting urine culture results. CRP and PCT have low accuracy for cystitis, but might be useful for pyelonephritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01530-9.

Clinical Features for the Diagnosis of Pediatric Urinary Tract Infections: Systematic Review and Meta-Analysis

PURPOSE

Accurate diagnosis of urinary tract infection in children is essential because children left untreated can experience permanent renal injury. We aimed to assess the diagnostic value of clinical features of pediatric urinary tract infection.

METHODS

We performed a systematic review and meta-analysis of diagnostic test accuracy studies in ambulatory care. We searched the PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, Health Technology Assessment, and Database of Abstracts of Reviews of Effects databases from inception to January 27, 2020 for studies reporting 2 × 2 diagnostic accuracy data for clinical features compared with urine culture in children aged <18 years. For each clinical feature, we calculated likelihood ratios and posttest probabilities of urinary tract infection. To estimate summary parameters, we conducted a bivariate random effects meta-analysis and hierarchical summary receiver operating characteristic analysis.

RESULTS

A total of 35 studies (N = 78,427 patients) of moderate to high quality were included, providing information on 58 clinical features and 6 prediction rules. Only circumcision (negative likelihood ratio [LR-] 0.24; 95% CI, 0.08-0.72; n = 8), stridor (LR- 0.20; 95% CI, 0.05-0.81; n = 1), and diaper rash (LR- 0.13; 95% CI, 0.02-0.92; n = 1) were useful for ruling out urinary tract infection. Body temperature or fever duration showed limited diagnostic value (area under the receiver operating characteristic curve 0.61; 95% CI, 0.47-0.73; n = 16). The Diagnosis of Urinary Tract Infection in Young Children score, Gorelick Scale score, and UTIcalc (https://uticalc.pitt.edu) might be useful to identify children eligible for urine sampling.

CONCLUSIONS

Few clinical signs and symptoms are useful for diagnosing or ruling out urinary tract infection in children. Clinical prediction rules might be more accurate; however, they should be validated externally. Physicians should not restrict urine sampling to children with unexplained fever or other features suggestive of urinary tract infection.

The Differential Diagnosis of Sterile Pyuria in Pediatric Patients: A Review

Sterile pyuria is a common finding in pediatric patients. Literature describing the diagnoses as well as clinical characteristics of children with sterile pyuria is lacking. This review was performed to establish an evidence-based approach to the differential diagnosis by way of an extensive literature search. The definition of pyuria is inconsistent. The various causes of pediatric sterile pyuria identified were classified as either Infectious or Non-Infectious. Sub-categories of Infectious causes include: Viral Infection, Bacterial Infection, Other Infections (tuberculosis, fungal, parasitic), Sexually Transmitted Infections, Recent Antibiotic Therapy. Non-Infectious causes include: Systemic Disease, Renal Disease, Drug Related, Inflammation adjacent to Genitourinary Tract. Clinicians that encounter pediatric patients with sterile pyuria and persistent symptoms should consider the substantial differential diagnosis described in this study.