Is screening urinalysis worthwhile in asymptomatic pediatric patients?

Use of urinalysis as a screening tool for asymptomatic infants

AIM

The utility of screening urinalysis in asymptomatic children has been questioned based on studies done in school-age children or adolescents. The American Academy of Pediatrics (AAP) recommended to abandon this screening in 2007 but many paediatricians perform it at some point during childhood. Thus, we aimed to investigate usefulness of screening urinalysis during infancy.

METHODS

We retrospectively reviewed results of screening urinalysis done in infants at 6-18 months of age who had regular care since birth at our centre. Infants with an ICD-10 (International Classification of Diseases, Tenth Revision) diagnostic code for routine child health exam (Z00.1) and a urinalysis requested with this code on the same date were included.

RESULTS

A total of 683 infants met the inclusion criteria. 44 (6%) had an abnormal urinalysis. The most common abnormality (n = 39, 5,7%) was pyuria. Of these 39 babies, 5 had a repeat urinalysis only, 18 had a repeat urinalysis with urine culture, and 16 had a urine culture alone. Six patients had positive culture results and were given antibiotic treatment. All six babies who received treatment had normal ultrasound and two patients had a voiding cystourethrography, which were also normal. The other abnormalities (n = 5) detected were microscopic hematuria and proteinuria. Repeat urinalyses of these patients were normal.

CONCLUSION

Screening urinalysis results were abnormal in 6% of the babies, but in 86% of those, abnormalities were transient. Only <1% had positive culture results. These data add to the evidence that screening urinalysis during infancy is unjustified supporting the AAP 2007 recommendations.

Benefit of urinalysis

OBJECTIVE

In the pilot Iran school screening programme, the minimal cost of screening dipstick urinalysis in 1601 asymptomatic school children was determined.

METHODS

The cost of screening dipstick urinalysis was calculated by reviewing the literature for the prevalence of asymptomatic proteinuria, hematuria, bacteriuria, and glucosuria determined by an initial dipstick urinalysis. The minimal cost utilizing data of 3 general physicians was calculated. Costs were determined by using current charge for supplies ordered to perform tests, charges for tests performed by a commercial laboratory, and the cost of a final evaluation by a pediatric nephrologist.

RESULTS

4.7% (76/1601) of patients were calculated to have an initial abnormal urinalysis. Upon retesting 1.37% (22/1601) of patients were calculated to have a persistent abnormality. The calculated cost was $167 to initially screen all 1601 patients with a dipstick urinalysis or $0.092 per patient. The calculated cost to evaluates the 22 patients with any persistent abnormality on repeat dipstick urinalysis was $0.02 or $0.001 per patient. This is the calculated cost for a single screening of 1601 asymptomatic pediatric patients.

CONCLUSION

Multiple screening dipstick urinalysis in asymptomatic pediatric is costly and should be discontinued. We propose that a single screening dipstick urinalysis be obtained at school entry age, between 6 and 7 years, in all asymptomatic children.

Evaluation of gross hematuria

Gross hematuria in children is a common complaint that often leads patients to seek urgent care. The diagnostic evaluation can be chosen based on specific patient history and physical examination. When a patient is asymptomatic, hypercalciuria and mild forms of glomerulonephritis are common causes of gross hematuria. Although they are less common in children, special care should be taken to investigate for renal and bladder tumors.

The abnormal urinalysis

The urinalysis is one of the most commonly performed tests in pediatrics, and whether expected or incidental, abnormal findings are common. Understanding the strengths and limitations of the urinalysis allows one to maximize its use as a screening tool while avoiding expensive and unnecessary evaluations. This article reviews the significance of abnormal results on urine dipstick testing and urine microscopy. Causes of false positive and false negative results are summarized. Initial diagnostic considerations of abnormal urinalysis findings are provided where appropriate.

Pediatricians' screening urinalysis practices

OBJECTIVE

To determine pediatricians' routine screening urinalysis practices.

STUDY DESIGN

This was a survey of a nationally representative sample of pediatricians practicing in the U.S. regarding their screening urinalysis practices in childhood.

RESULTS

Of the 1502 pediatricians sampled, 653 eligible subjects participated, for an estimated response rate of 49.5%. The vast majority of participants (78%) routinely screen asymptomatic children with urinalysis in at least 1 age group. Pediatricians' screening urinalysis practice varies based on age group: 9% screen during infancy (<1 year), 60% screen during early childhood (1 up to 5 years), 55% screen during late childhood (5 to 12 years), and 58% screen during adolescence (13 to 20 years). The majority of pediatricians (58%) routinely screen more than 1 age group. Some 38% of the pediatricians surveyed believe that the overall health of children is improved by screening all asymptomatic children with urinalysis.

CONCLUSIONS

Many pediatricians routinely conduct screening urinalysis during childhood, frequently at ages not recommended by the American Academy of Pediatrics.

Role of routine urinalysis in asymptomatic pediatric patients

This study was done to evaluate the spectrum of diagnoses and identify risk factors for significant kidney disease in asymptomatic children with proteinuria and/or microhematuria detected by routine urinalysis. Clinical and laboratory data were obtained by retrospective chart review of 239 patients referred to a tertiary care center. The predominant diagnosis in children with isolated microhematuria was hypercalciuria and with isolated proteinuria, orthostatic proteinuria. When microhematuria and proteinuria were present in combination, kidney disease was the predominant diagnosis. Urinalysis is a valuable tool to identify patients with kidney disease. The combination of microhematuria and proteinuria increases the risk of having significant kidney disease.

Pediatric urine testing

Today, urinalysis is one of the most common clinical tests ordered for adult and pediatric patients. Because urine specimens are usually readily available and are obtained noninvasively, the urine testing is well suited for children. This article discusses the most common urine tests performed in children for screening purposes and also less common tests for diagnosis of specific disorders. Special considerations regarding urine specimen collection in children are discussed. Some simple tests that are underused by clinicians are mentioned, as are some exciting new molecular applications of urine testing.

Technical report: urinary tract infections in febrile infants and young children. The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement

OVERVIEW

The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement has analyzed alternative strategies for the diagnosis and management of urinary tract infection (UTI) in children. The target population is limited to children between 2 months and 2 years of age who are examined because of fever without an obvious cause. Diagnosis and management of UTI in this group are especially challenging for these three reasons: 1) the manifestation of UTI tends to be nonspecific, and cases may be missed easily; 2) clean voided midstream urine specimens rarely can be obtained, leaving only urine collection methods that are invasive (transurethral catheterization or bladder tap) or result in nonspecific test results (bag urine); and 3) a substantial number of infants with UTI also may have structural or functional abnormalities of the urinary tract that put them at risk for ongoing renal damage, hypertension, and end-stage renal disease (ESRD).

METHODS

To examine alternative management strategies for UTI in infants, a conceptual model of the steps in diagnosis and management of UTI was developed. The model was expanded into a decision tree. Probabilities for branch points in the decision tree were obtained by review of the literature on childhood UTI. Data were extracted on standardized forms. Cost data were obtained by literature review and from hospital billing data. The data were collated into evidence tables. Analysis of the decision tree was used to produce risk tables and incremental cost-effectiveness ratios for alternative strategies.

RESULTS

Based on the results of this analysis and, when necessary, consensus opinion, the Committee developed recommendations for the management of UTI in this population. This document provides the evidence the Subcommittee used in the development of its recommendations.

CONCLUSIONS

The Subcommittee agreed that the objective of the practice parameter would be to minimize the risk of chronic renal damage within reasonable economic constraints. Steps involved in achieving these objectives are: 1) identifying UTI; 2) short-term treatment of UTI; and 3) evaluation for urinary tract abnormalities.

Screening dipstick urinalysis: a time to change

OBJECTIVE

This study attempted to determine the minimal cost of screening dipstick urinalyses in a hypothetical cohort of 2000 asymptomatic pediatric patients in a primary care setting.

METHODOLOGY

The minimal cost utilizing a private practitioner in an urban or suburban group pediatric setting was calculated. Costs were determined by using current charges for supplies ordered to perform tests in the office, charges for tests performed by a commercial laboratory, and the cost of an initial evaluation by a pediatric nephrologist. Data from published studies were also utilized.

RESULTS

Nine percent (179/2000) of patients were calculated to have an initial abnormal urinalysis. Upon retesting only 1.5% (29/2000) of patients were calculated to have a persistent abnormality. The calculated rate of a false positive/transient abnormality for all patients in the hypothetical cohort of 2000 asymptomatic pediatric patients was 84% (150/179). The calculated minimal cost for the outpatient evaluation of 2000 asymptomatic pediatric patients by dipstick urinalyses ranged between $5022 to $6475. The range depends on whether 50% versus 100% of patients with a repeat abnormal dipstick urinalysis were referred to a pediatric nephrologist for further evaluation. The calculated cost was $1290 to initially screen all 2000 patients with a dipstick urinalysis or 65 cents per patient. The calculated cost to evaluate the 29 patients with any persistent abnormality on repeat dipstick urinalysis was $3732 to $5185 or $129 to $179 per patient. This is the calculated cost for a single screening of 2000 asymptomatic pediatric patients. The calculated cost for four multiple screening urinalyses as currently recommended is $20 088 to $25 900. Additionally, these are only minimal initial calculated costs. Costs of any renal imagining or function studies ordered by the pediatric nephrologist or the pediatrician pursuing a further evaluation on his/her own were not included.

CONCLUSION

Multiple screening dipstick urinalyses in asymptomatic pediatric patients are costly and should be discontinued. In their place, we propose that a single screening dipstick urinalysis be obtained at school entry age, between 5 and 6 years old, in all asymptomatic children. The sample should be a first morning void.