Screening dipstick urinalysis: a time to change

Candida spp.: the burden of a microorganism in a microbiology department

There is no precise information available on the entire workload of isolating a specific microorganism in a clinical microbiology laboratory, and the costs associated with it have not been specifically estimated. In this descriptive retrospective study conducted at the microbiology department of a general teaching hospital from January 2021 to December 2022, we assessed the workload associated with identifying Candida species in all types of clinical samples and patients. Costs were estimated from data obtained from the hospital's finance department and microbiology laboratory cost records. In 2 years, 1,008,231 samples were processed at our microbiology department, of which 8,775 had one or more Candida spp. isolates (9,683 total isolates). Overall, 5,151 samples with Candida spp. were identified from 2,383 inpatients. We isolated Candida spp. from 515.3 samples/100,000 population/year and from 92 samples/1,000 hospital admissions/year. By sample type, 90.8% were superficial, mainly mucosal. Only 9.1% Candida spp. were isolated from deep, usually sterile, samples, being mostly from ordinarily sterile fluids. Candida albicans was the main species (58.5%) identified, followed by C. parapsilosis complex, C. glabrata, C. tropicalis, and C. krusei. In admitted patients, the incidences of samples with Candida spp. isolates were 302.7 samples/100,000 population/year and 54 samples/1,000 admissions/year. The average cost of isolating and identifying Candida spp. was estimated at 25€ per culture-positive sample. To our knowledge, this is the first attempt to gage the workload and costs of Candida spp. isolation at a hospital microbiology department. These data can help assess the burden and significance of Candida isolation at other institutions and also help design measures for streamlining.

IMPORTANCE

We believe that this work is of interest because at present, there is no really accurate information available on the total workload involved in isolating a specific microorganism in a clinical microbiology laboratory. The costs related to this have also not been described. We have described the unrestricted workload of Candida spp. in all types of samples for all types of species and patients. We believe that this information would be necessary to collect and share this information as well as to collect it in a standardized way to know the current situation of Candida spp. workload in all clinical microbiology laboratories.

Cost-Effectiveness of School Urinary Screening for Early Detection of IgA Nephropathy in Japan

Importance

The evidence for and against screening for chronic kidney disease in youths who are asymptomatic is inconsistent worldwide. Japan has been conducting urinary screening in students for 50 years, allowing for a full economic evaluation that includes the clinical benefits of early detection and intervention for chronic kidney disease.

Objectives

To evaluate the clinical effectiveness and cost-effectiveness of school urinary screening in Japan, with a focus on the benefits of the early detection and intervention for IgA nephropathy, and to explore key points in the model that are associated with the cost-effectiveness of the school urinary screening program.

Design, Setting, and Participants

This economic evaluation with a cost-effectiveness analysis used a computer-simulated Markov model from the health care payer's perspective among a hypothetical cohort of 1 000 000 youths aged 6 years in first grade in Japanese elementary schools, followed up through junior and high school. The time horizon was lifetime. Costs and clinical outcomes were discounted at a rate of 2% per year. Costs were calculated in Japanese yen and 2020 US dollars (¥107 = US $1).

Interventions

School urinary screening for IgA nephropathy was compared with no screening.

Main Outcomes and Measures

Outcomes were costs and quality-adjusted life-years (QALYs). Cost-effectiveness was determined by evaluating whether the incremental cost-effectiveness ratio (ICER) per QALY gained remained less than ¥7 500 000 (US $70 093).

Results

In the base case analysis, the ICER was ¥4 186 642 (US $39 127)/QALY, which was less than the threshold. There were 60.3 patients/1 000 000 patients in the no-screening strategy and 31.7 patients/1 000 000 patients in the screening strategy with an end-stage kidney disease. Cost-effectiveness improved as the number of screenings decreased (screening frequency <3 times: incremental cost, -¥75 [US $0.7]; incremental QALY, 0.00025; ICER, dominant), but the number of patients with end-stage kidney disease due to IgA nephropathy increased (40.9 patients/1 000 000 patients). Assuming the disutility due to false positives had a significant impact on the analysis; assuming a disutility of 0.01 or more, the population with no IgA nephropathy had an ICER greater than the threshold (¥8 304 093 [US $77 608]/QALY).

Conclusions and Relevance

This study found that Japanese school urinary screening was cost-effective, suggesting that it may be worthy of resource allocation. Key factors associated with cost-effectiveness were screening cost, the probability of incident detection outside of screening, and IgA nephropathy incidence, which may provide clues to decision-makers in other countries when evaluating the program in their own context.

Evaluation of Proteinuria and Hematuria in Ambulatory Setting

Proteinuria and/or hematuria are common findings in ambulatory settings. Proteinuria can be glomerular and/or tubular in origin and it may be transient, orthostatic, or persistent. Persistent proteinuria may be indicative of a serious kidney pathology. Hematuria, which denotes the presence of an increased number of red blood cells in the urine, can be gross or microscopic. Hematuria can originate from the glomeruli or other sites of the urinary tract. Asymptomatic microscopic hematuria or mild proteinuria in an otherwise healthy child is less likely to be of clinical significance. However, the presence of both requires further workup and careful monitoring.

Pulmonary Manifestations of Renal Disorders in Children

The causes of kidney disease in pediatric patients are evenly divided between congenital abnormalities of the kidney and urinary tract and acquired disorders. Nearly 10% to 15% of adults in the United States have chronic kidney disease (CKD); there are no comparable data in children. Regardless of patient age, CKD is a systemic problem that affects every organ system, including the lung. We review the tests used to diagnose and evaluate kidney disease and the main clinical syndromes that are likely to be encountered to aid the pulmonology consultant who is asked to evaluate patients with kidney disease.

Utility of screening urinalysis to detect abdominal injuries in suspected victims of child physical abuse

BACKGROUND

Urinalysis, liver enzymes (LE) and lipase are used to screen for abdominal injuries in children with suspected physical abuse (SPA). However, data on the utility of urinalysis is limited.

OBJECTIVES

Describe the prevalence of hematuria in evaluations for SPA. Determine test characteristics of hematuria, LE and lipase to identify kidney and other abdominal injuries among children with SPA.

PARTICIPANTS AND SETTING

Children < 7 years receiving a urinalysis during evaluation for SPA by a hospital child protection team.

METHODS

Demographic, clinical, and laboratory data including presence of hematuria (blood on urine dipstick), elevated LE (> 80 U/L) and elevated lipase (> 100 U/L) were abstracted retrospectively. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the overall study population and for patients without abdominal symptoms.

RESULTS

Ten percent of patients had hematuria (N = 237). Prevalence of abdominal and kidney injuries was 7 % and 1 % respectively. Of 3 patients with kidney injury, 2 had hematuria and all had elevated LE. Sensitivity (67 %) and NPV (99 %) of hematuria to detect kidney injuries were lower than LE and the same as lipase. Specificity (91 %) and PPV (8%) of hematuria to detect kidney injury were greater than LE and similar to lipase. Sensitivity of hematuria to detect any abdominal injury (50 %) was lower than LE (81 %). Sensitivity of hematuria to detect occult abdominal injury was 0 %.

CONCLUSIONS

Hematuria alone did not lead to detection of kidney injury. Test characteristics of hematuria were largely similar or inferior to LE and lipase.

How to use… urine dipsticks

'Urine dipstick', the commonly used point-of-care test, is an extremely sensitive investigation. Results of this test affected by numerous factors, if not meticulously linked with detailed history and examination, can lead a well-meaning clinician down the wrong clinical pathway. The aim of this article is to provide an overview of this every day test, touching on the physiological and technological basis initially, but mainly focusing on common questions like when to request the dipstick test, the correlation of dipstick results with urine specimen collected by different method and complexities of interpretation of dipstick results in everyday clinical scenarios.

Yield of Urinalysis Screening in Pediatric Cancer Survivors

BACKGROUND

The Children's Oncology Group (COG) publishes consensus guidelines with screening recommendations for early identification of treatment-related morbidities among childhood cancer survivors. We sought to estimate the yield of recommended yearly urinalysis screening for genitourinary complications as per Version 3.0 of the COG Long-Term Follow-Up Guidelines and identify possible risk factors for abnormal screening in a survivor population.

PROCEDURE

A database of pediatric cancer survivors evaluated between January 2008 and March 2012 at Children's Healthcare of Atlanta was queried for survivors at risk for genitourinary late effects. The frequency of abnormal urinalyses (protein ≥1+ and/or presence of glucose and/or ≥5 red blood cells per high power field) was estimated. Risk factors associated with abnormal screening were identified.

RESULTS

Chart review identified 773 survivors (57% male; 67% Caucasian; 60% leukemia/lymphoma survivors; mean age at diagnosis, 5.7 years [range: birth to 17.7 years]; time from diagnosis to initial screening, 7.6 years [range: 2.3 to 21.5 years]) who underwent urinalysis. Abnormal results were found in 78 (5.3%) of 1,484 total urinalyses. Multivariable analysis revealed higher dose ifosfamide (odds ratio [OR] = 6.8, 95% confidence interval [CI] 2.9-16.0) and total body irradiation (TBI, OR = 3.0, 95% CI 1.0-8.4) as significant risk factors for abnormal initial urinalysis screening.

CONCLUSIONS

Pediatric cancer survivors exposed to higher dose ifosfamide or TBI may be at higher risk of abnormal findings on urinalysis screening. Targeted screening of these higher risk patients should be considered.

Urinalysis in children and adolescents

BACKGROUND

Urinalysis is the most commonly performed biochemical test in infancy and early childhood. The urine sample should be correctly obtained, age-specific aspects should be considered, and age-dependent reference values should be used.

METHOD

This review is based on a selective literature search in electronic databases, textbooks, and guidelines from Germany and abroad on the acquisition of urine samples and the performance of urinalysis in infancy and early childhood.

RESULTS

The timing and mode of acquisition of the urine sample affect the assessment of hematuria, proteinuria, leukocyturia, nitrituria, and the uropathogenic bacterial colony count in the urine culture. Dipstick tests can be used for targeted screening for these features. The test results should be interpreted together with the findings of urine microscopy, the medical history, and the physical examination. Proteinuria should be quantified and differentiated; both of these things can be done either from collected urine or (especially in infants and young children) from a spontaneously voided urine sample, by determination of the protein/creatinine quotient. Orthostatic proteinuria in an adolescent requires no further evaluation or treatment. Hematuria should be characterized as either glomerular or non-glomerular erythrocyturia. Asymptomatic, isolated microhematuria in childhood is not uncommon and often transient; in the absence of a family history, it usually does not require an extensive work-up. Proteinuria combined with hematuria should arouse the suspicion of glomerulonephritis.

CONCLUSION

Urinalysis in infancy and early childhood is a simple and informative diagnostic test as long as the urine sample has been obtained properly and the results are interpreted appropriately for this age group.

Pediatric screening urinalysis: a difference-in-differences analysis of how a 2007 change in guidelines impacted use

BACKGROUND

Practice guidelines can promote higher-quality care, yet they are inconsistently adopted. The purpose of this study is to evaluate the impact of a 2007 American Academy of Pediatrics recommendation to discontinue routine screening urinalysis in children.

METHODS

Using data from the National Ambulatory Medical Care Survey, we used a difference-in-differences approach to estimate visit-level screening urinalysis proportions before (2005-2006, n = 1,247) and after (2008-2009, n = 1,772) the 2007 AAP recommendation. We compared visits by children 4-18 years old to visits by young adults aged 19-32. Analyses were adjusted for continuous patient age, patient race/ethnicity, physician specialty, and stratified by patient gender and visit setting.

RESULTS

The 2007 recommendation was associated with no significant change in adjusted visit-level screening urinalysis proportions in child visits (20.4% to 22.5%) compared to an increase in young adult visits (20.1% to 27.0%) - a differential impact of -4.8 percentage points (95% Confidence Interval [CI] -9.0, -0.5). In private practices, visit proportions differentially decreased by 7.6 percentage points (95% CI -13.7, -1.5) in female children and by 0.5 percentage points (95% CI -10.6, 9.6) in male children. In community health centers, visit proportions differentially decreased by 17.4 percentage points (95% CI -27.9, -6.8) in female children and by 33.5 percentage points (95% CI -47.4, -19.7) in male children.

CONCLUSIONS

A 2007 recommendation to discontinue routine screening urinalysis in children was associated with no change in use in child visits relative to an increase in use in adult visits. Overall, nearly one-quarter of child visits still included screening urinalysis.

The burden of hypertension and kidney disease in Northeast India: the Institute for Indian Mother and Child noncommunicable diseases project

Chronic noncommunicable diseases (NCDs) such as hypertension, atherosclerosis, acute myocardial infarction, stroke, diabetes, obesity, and chronic kidney disease are the major cause of death not only in high income, but also in medium and low income countries. Hypertension and diabetes, the most common causes of chronic kidney disease, are particularly common in southeast Asian Countries. Because early intervention can markedly slow the progression of these two killer diseases, assessment of their presence through screening and intervention program is a priority. We summarize here results of the screening activities and the perspectives of a noncommunicable diseases project started in West Bengal, India, in collaboration with the Institute for Indian Mother and Child (IIMC), a nongovernmental voluntary organization committed to promoting child and maternal health. We started investigating hypertension and chronic kidney disease with screen in school-age children and in adults >30 years old. We found a remarkable prevalence of hypertension, even in underweight subjects, in both children and adult populations. A glomerular filtration rate <60 mL/min was found in 4.1% of adult subjects significantly higher than that of 0.8% to 1.4% reported 10 years ago. Increased awareness and intervention projects to identify NCDs and block their progression are necessary in all countries.

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.

Chronic kidney disease and automatic reporting of estimated glomerular filtration rate: new developments and revised recommendations

The publication of the Australasian Creatinine Consensus Working Group's position statements in 2005 and 2007 resulted in automatic reporting of estimated glomerular filtration rate (eGFR) with requests for serum creatinine concentration in adults, facilitated the unification of units of measurement for creatinine and eGFR, and promoted the standardisation of assays. New advancements and continuing debate led the Australasian Creatinine Consensus Working Group to reconvene in 2010. The working group recommends that the method of calculating eGFR should be changed to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, and that all laboratories should report eGFR values as a precise figure to at least 90 mL/min/1.73 m(2). Age-related decision points for eGFR in adults are not recommended, as although an eGFR < 60 mL/min/1.73 m(2) is very common in older people, it is nevertheless predictive of significantly increased risks of adverse clinical outcomes, and should not be considered a normal part of ageing.If using eGFR for drug dosing, body size should be considered, in addition to referring to the approved product information. For drugs with a narrow therapeutic index, therapeutic drug monitoring or a valid marker of drug effect should be used to individualise dosing. The CKD-EPI formula has been validated as a tool to estimate GFR in some populations of non-European ancestry living in Western countries. Pending publication of validation studies, the working group also recommends that Australasian laboratories continue to automatically report eGFR in Aboriginal and Torres Strait Islander peoples. The working group concluded that routine calculation of eGFR is not recommended in children and youth, or in pregnant women. Serum creatinine concentration (preferably using an enzymatic assay for paediatric patients) should remain as the standard test for kidney function in these populations.

A study of online consultations for paediatric renal patients in Russia

We developed an educational website for parents of paediatric patients with kidney diseases in Russia. Parents could ask questions regarding their child's illness and submit information, including medical summaries and scanned or electronic images. A US-trained specialist in paediatric nephrology reviewed the information provided and advised about further evaluation or referral, as well as discussing possible treatment plans. In the first nine months, 141 distinct users communicated through the website. Fifty-eight percent of patients were female. An analysis of 70 cases suggested that in 45% there had been overdiagnosis of common paediatric problems, such as urinary tract infection and pyelonephritis. Users completed an anonymous satisfaction survey. The response rate was 84% (n = 59/70). The majority of respondents found the consultation useful (mean = 4.6 on a 5-point scale). The online consultation answered the questions of most respondents, provided useful information and relieved uncertainty regarding a follow-up. The majority of the respondents (>90%) confirmed that they trusted the online consultation and would recommend the technique to other parents. Online consultation for parents can provide reliable information that results in improved parental satisfaction and education. This approach may be useful in improving care and providing patient education in underserved areas in the USA and elsewhere.

A cost-effectiveness analysis of screening urine dipsticks in well-child care

OBJECTIVE

Despite data suggesting that routine urine screening for chronic kidney disease (CKD) has low diagnostic yield and the American Academy of Pediatrics 2007 recommendation to discontinue this screening, pediatricians may not have recognized this change. Because the new recommendation marks a major alteration in the practice guidelines, we sought to evaluate the cost-effectiveness of dipstick urinalysis for detection of CKD from the primary care practitioner's perspective.

METHODS

Decision analysis was used to model a screening dipstick urinalysis strategy relative to a no-screening strategy. Data on the incidence of hematuria and proteinuria in children were derived from published reports of large cohorts of school-aged children. Direct costs were estimated from the perspective of the primary care practitioner. The measure of effectiveness was the rate of diagnoses of CKD. Cost-effectiveness was evaluated by using an incremental cost-effectiveness ratio.

RESULTS

Expected costs and effectiveness for the no-screening strategy were 0 dollars because no resources were used and no cases of CKD were diagnosed. The screening strategy involved a cost per dipstick of 3.05 dollars. Accounting for both true-positive and false-positive initial screens, 14.2% of the patients required a second dipstick as per typical clinical care, bringing the expected cost of the screening strategy to 3.47 dollars per patient. In the screening strategy, 1 case of CKD was diagnosed per 800 screened, and the incremental cost-effectiveness ratio was 2779.50 dollars per case diagnosed.

CONCLUSIONS

Urine dipstick is inexpensive, but it is a poor screening test for CKD and a cost-ineffective procedure for the primary care provider. These data support the change in the American Academy of Pediatrics guidelines on the use of screening dipstick urinalysis. Clinicians must consider the cost-effectiveness of preventive care procedures to make better use of available resources.

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.

Screening for CKD in children: a global controversy

This review addresses the relevance of urinary screening for chronic kidney disease (CKD) in children. Ambiguity about screening children exists because of the uncertainty as to whether early detection of renal disorders in childhood will lead to effective interventions and reduction in the number of individuals who subsequently progress to ESRD. A related concern is whether the adoption of urinary screening programs is cost effective. The most common method that is used for screening children for CKD involves the measurement of spot samples of urine for hematuria and or proteinuria. Although mass screening is now well established in Japan, Taiwan, and Korea, there appears to be movement away from mass screening to detect CKD in children and adolescents in North America and Europe. In December 2007, the American Academy of Pediatrics published their latest recommendations, in which no urinalyses were recommended at any age during childhood. The second issue addressed in this review is the reporting of estimated glomerular filtration rates (GFR) in children by clinical laboratories.

Comparison between 24-h proteinuria, urinary protein/creatinine ratio and dipstick test in patients with nephropathy: patterns of proteinuria in dipstick-negative patients

OBJECTIVE

Three main tests are commonly employed for the measurement of proteinuria: the dipstick test, the urinary protein/creatinine ratio (P/C) and the 24-h urine collection. The aim of this study was to evaluate the correlation between these methods, comparing linear regression and ROC curve data.

MATERIAL AND METHODS

A total of 297 consecutive outpatients with different renal diseases were included in the study. Twenty-four-hour proteinuria was considered the reference test.

RESULTS

A high degree of correlation was observed between all the tests (p<0.0001), the highest regression coefficient being between 24-h proteinuria and P/C (R=0.82), and the lowest between P/C and the dipstick test (R=0.72). The dipstick test failed to detect pathological proteinuria in 94 patients (31.6%). Therefore, in these subjects, the patterns of proteinuria were assessed by immunofixation and sodium dodecyl sulphate (SDS) electrophoresis.

CONCLUSIONS

Our data strongly support the use of urinary P/C for the detection of proteinuria, at least in nephrology units, where the prevalence of proteinuria is likely to be high.

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.

The role of automated urine particle flow cytometry in clinical practice

Urine particle flow cytometers (UFC) have improved count precision and accuracy compared to visual microscopy and offer significant labor saving. The absence of an internationally recognized reference measurement procedure, however, is a serious drawback to their validation. Chamber counting by phase contrast microscopy of supravitally-stained uncentrifuged urine is considered the best candidate for reference. The UF-100 (Sysmex Corporation, Japan) identifies RBC, WBC, squamous epithelial cells, transitional epithelial and renal tubular cells (SRC), bacteria, hyaline and inclusional casts, yeast-like cells, crystals and spermatozoa, using argon laser flow cytometry. Evaluations have established acceptable linearity over useful working ranges, with an imprecision that is consistently and significantly less than microscopy, and with negligible carry-over. Comparisons of UFC with chamber counts, quantitative urine microscopy, sediment counts, test strips, bacterial culture and urine density are reviewed. Clinical studies include diagnosis and monitoring of urinary tract infection; localization of the sites of hematuria; and diagnosis, monitoring and exclusion of renal disease. The most popular approach is to combine test strips with UFC for primary screening either always by both methods or by using test strips for analytes unrelated to particles analyzed by UFC. Expert systems now exist combining both test modalities based on user definable decision rules. The implementation of such a strategy significantly reduces microscopy review and saves time and expense without diminishing clinical utility.