Dipstick chemical urinalysis: an accurate cost-effective screening test

Preoperative dipstick albuminuria is associated with acute kidney injury in high-risk patients following non-cardiac surgery: a single-center prospective cohort study

PURPOSE

This study aimed to investigate the association between preoperative dipstick albuminuria (DA) and acute kidney injury (AKI) in high-risk patients following non-cardiac surgery.

METHODS

This was a single-center prospective cohort study. Adult patients with high risk of AKI undergoing non-cardiac surgery were enrolled. The primary outcome was AKI, defined according to KDIGO criteria within 7 days following non-cardiac surgery. DA status was determined by urinalysis performed within 24 h of hospital admission. Multivariate logistic regression model was used to analyze the association between preoperative DA and postoperative AKI.

RESULTS

During the study period, 552 patients were enrolled and 8.5% of them developed postoperative AKI. The overall rate of preoperative positive DA was 26.4% with 30 and ≥ 100 mg/dL DA accounting for 19.2% and 7.2%, respectively. Patients with more severe preoperative DA had much higher rate of postoperative AKI (5.2% in patients with negative or trace DA, 13.2% in patients with 30 mg/dL DA and 30.0% in patients with ≥ 100 mg/dL DA, P < 0.001). After adjusting for several perioperative variables, preoperative 30 mg/dL DA (OR 2.575; 95% CI 1.049-6.322; P = 0.039) and ≥ 100 mg/dL DA (OR 3.868; 95% CI 1.246-12.010; P = 0.019) showed an independent association with postoperative AKI. In addition, patients with higher DA status demonstrated significantly increased level of postoperative urine biomarkers and their ratio to urine creatinine.

CONCLUSIONS

Preoperative DA was independently associated with AKI in high-risk patients following non-cardiac surgery. Preoperative routine urinalysis for determination of DA status was suggested in early risk stratification.

Exertional hematuria: definition, epidemiology, diagnostic and clinical considerations

Exertional hematuria can be considered a subcategory of exercise-induced hematuria, characterized by painless appearance of erythrocytes in urine after recent physical exercise, not directly attributable to external traumatic injuries to the genitourinary system, and spontaneously resolving with rest. Although its frequency has enormous heterogeneity, depending on the athlete population, duration and intensity of exercise, technique used for identifying or quantifying hematuria and relative diagnostic thresholds, what clearly emerges from the scientific literature is that a certain degree of hematuria is commonplace after non-contact sports, especially running. This exertional hematuria, which appears self-limiting, may be attributable to some frequently concomitant causes, involving organs of the genitourinary system, and mostly encompassing bladder or urethral injuries. Renal injuries caused by internal movements, vascular spasm and ischemia are also potential causes of increased glomerular permeability to erythrocytes, whilst the presence of preexisting genitourinary diseases cannot be ruled out, especially when post-exercise hematuria is recurrent or endures. Therefore, whenever hematuria is observed in a random urine specimen, recent sports performance (especially running) should be investigated and urinalyses scheduled for the following days. When no temporal association of hematuria with exercise can be found, when genitourinary traumas have been excluded or hematuria persists for >72 h, specific diagnostic investigations should be planned to identify possible genitourinary diseases.

Referral Patterns for the Evaluation of Asymptomatic Microscopic Hematuria in Women in a Single Health Care System: Room for Improvement

OBJECTIVE

To identify patterns of care for women referred for asymptomatic microhematuria in a single, hospital-based health care system and estimate the cost of unindicated evaluation.

METHODS

We conducted a retrospective study of 100 women with a diagnosis of asymptomatic microhematuria referred to a tertiary female pelvic medicine and reconstructive surgery practice. Our analysis focused on referral patterns by obstetrician-gynecologists and primary care physicians. Data analyzed included whether asymptomatic microhematuria was documented using urine microscopy (vs urine dipstick) and whether the urine microscopy correctly identified asymptomatic microhematuria with three red blood cells (RBCs).

RESULTS

Forty-six patients were referred who met the American Urological Association's guidelines for asymptomatic microhematuria with a workup estimated at $8,298 per patient. Fifty-four were referred to a female pelvic medicine and reconstructive surgery specialist despite clearly not meeting the American Urological Association's definition of asymptomatic microhematuria. Of these, 33 patients were referred based on dipstick-positive results only, 11 were referred based on microscopic urinalysis demonstrating fewer than three RBCs per high-power field (HPF), and the remaining 10 patients were referred with urine microscopy demonstrating at least 3 RBC/HPF but in the setting of a clearly benign cause, such as infection or menstruation. The total estimated cost of the unnecessary asymptomatic microhematuria workup in patients who did not meet American Urological Association criteria for referral was $1,213 per patient.

CONCLUSION

Fewer than half of the referrals for asymptomatic microhematuria were appropriate, leading to wasted and entirely preventable health care expenditures. This study highlights the need for education of health care providers making these referrals.

Ascorbic acid-A black hole of urine chemistry screening

BACKGROUND

Study was performed in order: (i) to assess the comparability of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; (ii) to assess accuracy of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; and (iii) to evaluate interference of ascorbic acid on the glucose, bilirubin, hemoglobin, and nitrite determination using 2 different dipsticks: iChem Velocity, Iris Diagnostics and Combur-10M, Roche Diagnostics.

METHODS

Random urine specimens were included in the study. Comparability, accuracy, and ascorbic acid interference testing were performed.

RESULTS

Obtained results have shown almost perfect agreement for all parameters between 2 dipsticks in samples with negative ascorbic acid. Agreement in samples with positive ascorbic acid was not acceptable for bilirubin, protein, nitrite, and hemoglobin. Accuracy was not acceptable for hemoglobin and leukocyte esterase on both dipsticks. Ascorbic acid interference examination has shown that intensity of interference differs between dipsticks. Ascorbic acid interferes with glucose, hemoglobin, nitrite, and bilirubin at different concentrations causing false-negative results.

CONCLUSION

Obtained results indicate that it is necessary to determine diagnostic accuracy of used dipstick in order to define purpose of urinalysis. It is very important to choose dipstick with ascorbic acid indicator and to examine ascorbic acid impact on dipstick analytes independently of manufacturer claims.

Urinary screening for detection of renal abnormalities in asymptomatic school children

Background

Urinary screening tests for early detection of renal diseases in asymptomatic school children and adolescents are important in the detection of silent renal diseases.

Objectives

The purpose of the study was to determine the prevalence of occult renal diseases by dipstick test (reagent strips) in asymptomatic Nepalese children.

Patients and Methods

A total of 2,243 school children, aged 5–15 years, were screened for urinary abnormalities using dipstick test screening. The children who tested positive in the first screening were re-tested after 2–4 weeks.

Results

In the first screening, 123 children (5.5%) tested positive for isolated hematuria and proteinuria and for combined hematuria and proteinuria. Of these children, 16 (0.71%) cases tested positive in a second screening. Subsequently, 1 child from the secondary screening group was lost to follow up, 5 tested normal and 10 revealed abnormalities. Glomerulonephritis was the most commonly detected disorder (50%).

Conclusions

Urinary screening was found to be useful in identifying occult renal diseases in asymptomatic children. Urinary screening would therefore not only help in early detection but also in the prevention of the deterioration of renal function later in life.

The rate of manual microscopic examination of urine sediment: a College of American Pathologists Q-Probes study of 11,243 urinalysis tests from 88 institutions

CONTEXT

The manual microscopic examination (MME) of the urine sediment is an imprecise and labor-intensive procedure. Many laboratories have developed rules from clinical parameters or urinalysis results to limit the number of these examinations.

OBJECTIVE

To determine the rate of urinalysis specimens on which an MME of the urine sediment was performed, document how various rules influence this rate, and determine whether any new information was learned from the MME.

DESIGN

Participants selected 10 random urinalysis tests received during each traditional shift and determined if an MME was performed until a total of 50 urinalysis tests with an MME were reviewed. Participants recorded the rules that elicited an MME and any new information learned from such an examination.

RESULTS

The MME rate for the median institution was 62.5%. An MME of urine was most frequently done for an abnormal urinalysis result and often resulted in new information being learned, irrespective of the rule that elicited the MME. The median institution learned new information as a result of the manual examination 66% of the time. The use of an automated microscopic analyzer was associated with fewer manual examinations (P = .005), whereas the ability of a clinician to order a manual examination was associated with more manual examinations (P = .004).

CONCLUSIONS

The use of an automated microscopic analyzer may decrease the number of MMEs. An MME when triggered by an abnormal macroscopic appearance of urine, a physician request, or virtually any positive urinalysis result often resulted in new information.

National practice recommendations for hematuria: how to evaluate in the absence of strong evidence?

Hematuria is one of the most common conditions confronting clinical urologists and is present in many genitourinary pathology conditions. Although researchers have studied hematuria symptoms in an effort to determine the best diagnostic pathway, the existing lack of scientific evidence has created variations in clinical practice. The literature does not provide enough evidence to significantly alter the need to assess these patients. Consequently, many patients with microscopic or gross hematuria undergo low-yield workups that include invasive testing and imaging with radiation. In 2007, a national group of Kaiser Permanente (KP) urology chiefs agreed that national practice recommendations were needed to address existing variations in the management and workup of hematuria. Using a KP guideline methodology, the group reached a consensus agreement on the following recommendations: 1) referral to urology is recommended for all people with gross hematuria or high-grade hematuria (>50 red blood cells per high-power field [RBCs/HPF]) on a single urinalysis (UA); 2) referral to urology and urologic evaluation is recommended for men or women with asymptomatic microscopic hematuria or symptomatic hematuria that produces >3 RBCs/HPF on two of three properly performed and collected urinalyses; and 3) voided urinary cytology should be eliminated from asymptomatic hematuria screening protocol. The test is not sensitive enough to obviate further workup if findings are negative, and elimination of this screening test is estimated to save millions of dollars across the US. Hematuria on a UA should be reported as 0 to 3 RBC/HPF, 4 to 10 RBC/HPF, 11 to 25 RBC/HPF, 26 to 50 RBC/HPF, >50 RBC/HPF, or gross hematuria. This approach will also reduce radiation exposure.

Urine cytology and urine-based markers for bladder urothelial carcinoma detection and monitoring: developments and future prospects

Bladder cancer is currently diagnosed using cystoscopy and cytology in patients with suspicious signs and symptoms. These tests are also used to monitor patients with a history of bladder cancer. The recurrence rate for bladder cancer is high, thus necessitating long-term follow-up. Urine cytology has a high sensitivity and specificity for the detection of high-grade urothelial carcinoma, but lacks the sensitivity to detect low-grade tumors. Recently, multiple noninvasive urine-based bladder cancer tests have been developed. Many markers (BTA stat®, BTA TRAK®, ImmunoCyt™, NMP22® and UroVysion™) have already been approved by the US FDA for bladder cancer surveillance, while other markers are still undergoing development, preclinical and clinical investigation. An ideal bladder cancer test would be noninvasive, highly sensitive and specific, inexpensive, easy to perform and yield highly reproducible results. Many of the tests reviewed herein meet some, but not all, of these criteria.

Strategies for national health care systems in emerging countries: the case of screening and prevention of renal disease progression in Bolivia

There are close to 1 million people in the world who are alive simply because they have access to one form or another of renal replacement therapy (RRT). Ninety percent live in high-income countries. Little is known of prevalence and incidence of chronic kidney disease and of end-stage renal disease (ESRD) in middle-income and low-income countries, where the use of RRT is scarce or nonexistent. However, no intervention is undertaken, these people will experience progression to ESRD and death from uremia, because RRT is out of reach for them. These are the individuals for whom efforts should be focused to prevent or delay progression toward ESRD. In 1992, the Mario Negri Institute for Pharmacological Research in Bergamo, Italy, with the cooperation of the young doctors of the Ospedale Giovanni XXIII in La Paz (Bolivia), activated a specific project titled "El Proyecto de Enfermedades Renales en Bolivia" (The Project for Renal Diseases in Bolivia). The project sought to demonstrate that in emerging countries the best strategies against renal disease are prevention and early detection. After proper training of local personnel at the Clinical Research Center "Aldo e Cele Dacco" of the Mario Negri Institute in Bergamo, Italy, an educational campaign titled "First Clinical and Epidemiological Program of Renal Diseases"-under the auspices of the Renal Sister Center Program of the International Society of Nephrology-was conducted in 3 selected areas of Bolivia, including tropical, valley, and plains areas. The goal was to define the frequency of asymptomatic renal disease in these areas by screening a large population of patients at relatively low costs. The screening was formally performed at first-level health centers (Unidad de Salud). Participants were instructed to void a clean urine specimen, and a dipstick test was performed. Patients with positive urinalysis were enrolled in a follow-up program with subsequent laboratory and clinical checks. The study was conducted by 21 clinical centers. Apparently healthy patients (14,082) were enrolled over a period of 7 months. Urinary abnormalities were found on first screening in 4261 patients, but only 1019 patients (23.9%) were available for follow-up. At second urinalysis, 35% of patients had no abnormalities. In the remaining positive group of patients, further investigations disclosed the following abnormalities: urinary tract infection (48.4%), isolated hematuria (43.9%), chronic renal failure (1.6%), renal tuberculosis (1.6%), and other diagnoses 4.3% (kidney stones, 1.3%; diabetic nephropathy, 1%; polycystic kidney diseases, 1.9%). The experience gained from this initial screening program formed the basis for a second study aimed to prevent renal disease progression in a selected Bolivian population with high altitude polycythemia. In conclusion, our studies show that mass screening of the population for renal disease is feasible in developing countries and can provide useful information on frequency of renal diseases. Also, in patients with altitude polycythemia, long-term treatment with low doses of enalapril safely prevents increase in arterial blood pressure and progressively reduces hematocrit and proteinuria. Aside from its scientific value, this last study can be taken as an example of how, by rationalizing resources and investing in research programs, renal disease progression and cardiovascular risk may eventually improve, which ultimately should translate into less demand for dialysis, and thus provide alternatives to costly RRT. The transformation of the Bolivian pilot model into a systematic program applicable to most emerging countries may be seen as a task of national nephrology societies, along with methodologic and economic support of international bodies.

Current bladder cancer tests: unnecessary or beneficial?

Bladder cancer is currently diagnosed using cystoscopy and cytology in patients with suspicious signs and symptoms. These same tests are used to monitor patients with a history of bladder cancer for recurrence. The recurrence rate for bladder cancer is high, thus necessitating long-term follow-up. Urine cytology requires an experienced cytopathologist and is costly. It has high specificity, but low sensitivity for low-grade bladder tumors. Recently many non-invasive bladder cancer tests, utilizing markers found in the urine, have been developed. The FDA has approved several of these for the use is bladder cancer diagnosis, and many others are undergoing development and investigation. An ideal bladder cancer test would be non-invasive, highly sensitive and specific, inexpensive, easy to perform, and yield highly reproducible results. Many of the tests reviewed meet some, but not all, of these criteria.

Prevalence of hematuria among Zuni Indians with and without diabetes: The Zuni kidney Project

BACKGROUND

There is an epidemic of kidney disease among the Zuni Indians. In contrast to other American Indian tribes, the epidemic among the Zuni Indians is attributable to diabetic and nondiabetic renal disease.

METHODS

The Zuni Kidney Project, established to reduce the burden of renal disease, conducted a population-based cross-sectional survey of Zuni Indians aged 5 years or older to precisely estimate the prevalence of hematuria. The survey used neighborhood household clusters as the sampling frame to maximize ascertainment and minimize bias. During the survey, we administered a questionnaire; collected blood and urine samples; and measured blood pressure, height, and weight.

RESULTS

Age and sex distributions in our sample (n = 1,469) were similar to those of the eligible Zuni population (n = 9,228). Prevalences of hematuria, defined as dipstick of trace or greater and 50 red blood cells/microL or greater, age- and sex-adjusted to the Zuni population aged 5 years or older, were 33.2% (95% confidence interval [CI], 30.7 to 35.6) and 17.8% (95% CI, 15.8 to 19.8), respectively. Hematuria of trace or greater was more common among females (40.6%; 95% CI, 37.0 to 44.1) than males (25.1%; 95% CI, 21.8 to 28.4). Hematuria of trace or greater was common among Zuni Indians without diabetes (females, 39.7%; 95% CI, 35.7 to 43.8; males, 22.7%; 95% CI, 19.4 to 26.1) and with diabetes (females, 47.5%; 95% CI, 39.8 to 55.2; males, 45.8%; 95% CI, 34.3 to 57.3). Diabetes and alcohol use for greater than 10 years were associated with hematuria among males, but not females.

CONCLUSION

The prevalence of hematuria is high among Zuni Indians with and without diabetes. These findings are consistent with the hypothesis that nondiabetic kidney disease is common among Zuni Indians with and without diabetes.

Detection and diagnosis of blood in feces and urine: an overview

BACKGROUND

Detection of blood in feces or urine has long been regarded as an indicator of patient's state of health. The ease with which feces or urine may be obtained and patient's willingness to provide the specimen make detection of fecal occult blood or urine analysis one of the most commonly performed screening examinations. Historically, the inspection of feces or urine for diagnostic purpose has been practiced for centuries. Of late, management of renal or urinary tract abnormalities or investigation of anemia, gastrointestinal diseases and for early detection of colorectal cancer has assumed greater importance.

METHODS

The never-ending list of techniques for the diagnosis of disorders producing bleeding such as urine microscopy, urine cytology, urine based marker test, cytoscopy, ultra sonography, computed tomography, magnetic resonance imaging, to mention a few, and four categories of detection of fecal occult blood namely, radioanalytical, physical, immunochemical and chemical methods makes the study very interesting.

PURPOSE

This review attempts to overview various techniques, methods and methodologies for the diagnosis and detection of blood in feces and urine, in the direction of looking at past and current tests with an eye on future needs.

Comparison of test characteristics of urine dipstick and urinalysis at various test cutoff points

STUDY OBJECTIVE

We compare the test characteristics of urine dipstick and urinalysis at various test cutoff points in women presenting to emergency departments and an intermediate care center with symptoms of urinary tract infection.

METHODS

This was a prospective, observational study of adult women presenting to 1 of 2 community hospital EDs or an intermediate care center with dysuria, urgency, or urinary frequency on history, or suprapubic or costovertebral angle tenderness on examination. Patients who had taken antibiotics in the past 72 hours, had indwelling Foley catheters, symptomatic vaginal discharge, diabetes mellitus, immunodeficiency disorders, or were unable to provide a reliable history were excluded. The patient's clean-catch or catheterized urine specimen was tested immediately by a nurse using a Multistix 9 SG reagent strip. A second aliquot was sent within 1 hour of collection to the hospital laboratory, where a semiautomated microscopic urinalysis and a urine culture were performed. A positive urine culture was defined as more than 100,000 colonies of 1 or 2 uropathogenic bacteria per mL of urine at 48 hours. Dipstick and urinalysis data were compared with urine culture results. Sensitivity, specificity, and predictive values were calculated at various definitions of a positive test, or "test cutoff points," for combinations of leukocyte esterase, nitrite, and blood on dipstick and for RBCs and WBCs on urinalyses. The probability of an erroneous decision to withhold treatment on the basis of a negative test result was defined as "undertreatment," or 1 minus the negative predictive value. "Overtreatment" was defined as 1 minus the positive predictive value.

RESULTS

Three hundred forty-three patients were enrolled in this study. Twelve patients were withdrawn because of missing laboratory results. Forty-six percent (152/331) of patients had positive urine cultures. If urine dipstick results are defined as positive when leukocyte esterase or nitrite is positive or blood is more than trace, the overtreatment rate is 47% (156/331) and the undertreatment rate is 13% (43/331). If urinalysis results are defined as positive when WBCs are more than 3 per high-power field or RBCs are more than 5 per high-power field, the overtreatment rate is 44% (146/331) and the undertreatment rate is 11% (36/331). Matched pairs of test characteristics were identified when the analysis was repeated using more than 10,000 colonies per mL as a positive culture.

CONCLUSION

In this patient population, similar overtreatment and undertreatment rates were identified for various test cutoff points for urine dipstick tests and urinalysis. Although a urine dipstick may be equivalent to a urinalysis for the diagnosis of urinary tract infection, the limitations in the diagnostic accuracy of both tests should be incorporated into medical decisionmaking.

Evaluation of asymptomatic microscopic hematuria

Asymptomatic microscopic hematuria continues to be a common cause for urologic referral. Depending on the population under investigation, the condition is reported in 0.2% to 21.1% of subjects. Many possible etiologies exist for the presence of asymptomatic microscopic hematuria, ranging from insignificant lesions to potentially life-threatening lesions that may require urgent treatment. A cause for asymptomatic microscopic hematuria can be determined in 32% to 100% of patients undergoing a full urologic evaluation, with 3.4% to 56% of these patients having either moderately or highly significant lesions at the time of diagnosis. Consequently, full urologic evaluation is warranted in the majority of patients referred to a urologist with asymptomatic microscopic hematuria. In patients in whom no diagnosis is reached after initial evaluation, follow-up is necessary, although the extent and timing of such follow-up have not been adequately investigated. The ultimate goal of evaluating any patient with asymptomatic microscopic hematuria is the discovery of a significant lesion at an early stage when it is amenable to curative therapy and prior to that lesion causing significant morbidity. No randomized, prospective studies have compared the outcomes of patients with asymptomatic microscopic hematuria undergoing full evaluation with those of patients undergoing surveillance only. The data obtained in high-risk groups undergoing urinary dipstick screening for bladder cancer suggest that the bladder tumors discovered when evaluating all patients with asymptomatic microscopic hematuria may be more amenable to treatment than those normally encountered, thereby possibly reducing the mortality and morbidity associated with bladder cancer in these patients. These findings support the evaluation of patients with asymptomatic microscopic hematuria in a cost-conscious medical environment.

Haematuria

Many serious and potentially treatable diseases of the urinary tract may have haematuria as their only manifestation. However, asymptomatic microscopic haematuria detected by dipstick testing may be seen in up to 16% of screening populations. The great majority of such cases will have no sinister underlying cause, particularly in those under 40 years of age, and so the schedule of further investigations, some of which may be invasive, time-consuming and expensive, needs to be rationalised. In addition, the increasing popularity of 'fast track' clinics for the investigation of haematuria enhances the need for a clear strategy of investigation. Analysis of the epidemiology of asymptomatic haematuria and its causes combined with a consideration of the risk-benefit profile of the available investigations, makes it possible to set out an algorithm for the initial management of this common finding. Careful clinical assessment and basic laboratory tests for renal function, analysis of the urinary sediment and cytological examination of the urine are followed by ultrasound and plain radiography of the urinary tract. Flexible cystoscopy under local anaesthetic is central to the algorithm in patients of all ages. The importance of a nephrological opinion and consideration of renal biopsy, especially in younger patients with other evidence of glomerular disease, is stressed. The role of intravenous urography in excluding pathology of the upper urinary tract, especially in patients over the age of 40, is also considered.

Evaluation of asymptomatic microhematuria

OBJECTIVES

The purpose of this study was to evaluate a comprehensive urine cytodiagnostic assay to assist in localizing the site of origin and the etiology of asymptomatic microhematuria. This analysis, which assesses various qualitative and quantitative aspects of the voided urine, is compared simultaneously with controls obtained from the established routine urologic evaluation.

METHODS

One hundred consecutive subjects who presented solely for the evaluation of asymptomatic microhematuria were evaluated by the established routine urologic evaluation and a refined urine cytodiagnostic assay. For the purpose of this study, only calculi and neoplasms were considered significant findings.

RESULTS

The incidence of significant urologic disease was 13% (3 renal neoplasms, 2 urothelial bladder carcinomas, and 8 urinary calculi). The refined urine cytodiagnostic assay identified both uroepithelial vesical neoplasms, 7 of the 8 urinary calculi, and none of the 3 renal neoplasms. The presence of dysmorphic urinary red blood cells (RBCs) and RBC casts was strongly suggestive of renal parenchymal bleeding. Overall, 43 of 44 subjects (98%) with dysmorphic RBCs and RBC casts failed to demonstrate any significant urologic etiology.

CONCLUSIONS

These preliminary results suggest that the refined cytodiagnostic urine assay may be helpful in distinguishing whether a given patient's microhematuria is of a significant urologic or a renal parenchymal cause. The addition of this specialized urinalysis may prove a useful adjunct in improving the diagnostic yield in patients with asymptomatic microhematuria.

Repeat testing for haematuria and underlying urological pathology

OBJECTIVE

To assess the incidence of urological pathology in a group of patients referred for the investigation of haematuria and whose symptoms had resolved at the time of investigation.

PATIENTS AND METHODS

The results from examination of 395 patients attending for investigation of haematuria were analysed. The group comprised 198 men and 197 women with a mean age of 51 years (range 19-73).

RESULTS

In 220 patients (56%) no evidence of haematuria was detected despite its diagnosis in all patients at the time of referral. One-hundred and thirteen patients (51%) without detectable haematuria had urological pathology and 16 of these (14%) had an underlying malignancy in the urinary tract.

CONCLUSION

Repeat urine analysis to determine whether haematuria persists has been considered as a way to define a high risk group which requires urgent investigation. Our results clearly indicate that the finding of haematuria, even in one urine specimen, warrants full urological assessment.

Hematuria: essentials of diagnosis

Relatively common and often serious, hematuria has numerous causes requiring differing management strategies. Diagnostic guidelines are given.

Comparison of urine dipstick, microscopy, and culture for the detection of bacteriuria in children

The authors compared dipstick tests for leukocyte esterase and nitrite and microscopic examination of urinary sediment with urine culture to assess whether the former tests could reliably rule out bacteriuria in specimens from children. The authors studied urine specimens from 1010 infants and children younger than age 18. Compared with culture at greater than or equal to 10(5) colony forming units (cfu)/ml, the sensitivities of leukocyte esterase, nitrite, and microscopic examination of white blood cells (greater than or equal to 5 wbc/hpf) or bacteria (in at least moderate numbers) were 76 percent, 29 percent, 82 percent, and 80 percent, respectively. The specificities of the same tests were 81 percent, 99 percent, 81 percent, and 83 percent, respectively. Compared with culture at greater than or equal to 10(4) cfu/ml, the sensitivities of the tests were 64 percent, 21 percent, 64 percent, and 59 percent; the specificities were 82 percent, 99 percent, 81 percent, and 83 percent, respectively. The negative predictive values of leukocyte esterase and microscopic examinations of urinary sediment for white blood cells and bacteria were all 95 percent (greater than or equal to 10(4) cfu/ml) or 98 percent (greater than or equal to 10(5) cfu/ml). The authors conclude that the leukocyte esterase test is as accurate as sediment microscopy in identifying urine specimens from infants and children harboring less than 10(4) or less than 10(5) cfu/ml.

Dipstick haematuria and bladder cancer in men over 60: results of a community study

OBJECTIVE

To investigate the prevalence and relevance of dipstick haematuria in a group of men in the community.

DESIGN

Prospective study of elderly men invited to attend a health centre for urine screening as part of a health check.

SETTING

An inner city health centre in Leeds.

SUBJECTS

578 Of 855 men aged 60-85 responding to an invitation to participate.

INTERVENTIONS

The subjects had their urine tested with a dipstick (Multistix) for the presence of blood and then tested their urine once a week for the next 10 weeks. Those with one or more positive test results were offered full urological investigation.

MAIN OUTCOME MEASURE

The prevalence of urological disease in those subjects with dipstick haematuria.

RESULTS

78 Men (13%) had dipstick haematuria on a single test and a further 54 (9%) had evidence of dipstick haematuria when testing their urine once a week during a subsequent 10 week period. Investigation of 87 men disclosed urological disease in 45, including four with a bladder tumour and seven with epithelial dysplasia.

CONCLUSION

Dipstick haematuria is a common incidental finding in men over 60 and is associated with appreciable urological disease. The introduction of less invasive methods of investigation, particularly flexible cystoscopy and ultrasonography, has made investigation of these patients simple and safe and makes screening for bladder cancer in the community more feasible.

Evaluation of colorimetric dipstick test to detect alcohol in saliva: a pilot study

The Alco Screen Saliva Dipstick is an inexpensive, easy-to-use, colorimetric test that gives a semiquantitative estimation of the blood alcohol value by measuring the relative concentration of salivary alcohol. To evaluate its accuracy, we compared the results from tests with the Alco dipstick with values from simultaneously measured blood alcohol tests in 53 patients who were suspected of having ingested alcohol. The correlation between Alco dipstick results and blood alcohol values was strong (r [Spearman's rho], + .91). When the blood alcohol concentration was 0.1 g/dL or more, the Alco dipstick test was 90.9% sensitive, 71.4% specific, and 92% efficient. At Alco dipstick values of 0.02 and 0.05 g/dL, however, semiquantitative concordance was unsatisfactory. Nevertheless, even at the 0.05-g/dL value of salivary alcohol, the test was still valuable as a screen of de facto alcohol ingestion. Definitive diagnosis of relative alcohol intoxication requires confirmatory breath or blood alcohol concentrations by standard methodologies.

Reliability of a urine dipstick in emergency department patients

We conducted a study to examine whether a negative Chemstrip 9 result for leukocyte esterase and nitrite would reliably exclude an abnormal microscopic examination of the urine of emergency department patients. Three hundred urine specimens were subjected to Chemstrip 9 evaluations and full microscopic examinations in the microscopy laboratory. As the microscopy laboratory examination identified lower WBC and bacteria counts, increasing numbers of false-negative urine dipsticks results occurred. The results of our study reveal that the nitrite and leukocyte esterase assays miss significant microscopic findings with corresponding clinical pathology, with the nitrite examination being the less sensitive of the two tests. Based on our results, we believe it would not be prudent to use the Chemstrip 9 dipstick in the ED to exclude the presence of WBC and bacteria in the urine.

The significance of adult hematuria: 1,000 hematuria evaluations including a risk-benefit and cost-effectiveness analysis

Between March 1976 and June 1985, 1,000 consecutive adults with asymptomatic gross or microscopic hematuria in the absence of proteinuria were evaluated urologically. Lesions that could account for the hematuria were detected in 88.3 per cent of the patients. Life-threatening lesions were diagnosed in 9.1 per cent of the patients, while lesions requiring at least observation were present in 22.8 per cent. The incidence of life-threatening lesions increased with age, with a sharp increase after age 50 years. Life-threatening lesions were more common in men (13.6 per cent) than in women (4.9 per cent). In general, as the degree of hematuria increased so did the yield of life-threatening lesions; however, there was no "safe" lower limit of hematuria. Of the patients with life-threatening lesions 18.6 per cent had at least 1 urinalysis with less than 3 red blood cells per high power field within 6 months of the diagnosis. The direct medical cost of a hematuria evaluation was $777. The difference in direct medical costs to diagnose and treat localized versus metastatic genitourinary cancer was $48,070 in 3 matched pairs of patients. In this study group 77 of 84 patients (92 per cent) diagnosed with genitourinary cancer had localized disease. A hematuria evaluation was cost-effective for all groups studied. A literature-based estimate of the life-threatening risks of diagnostic studies applied to the study data resulted in a 1.1 per cent life-threatening risk per hematuria evaluation. For all categories studied, except for women less than 40 years old with microscopic hematuria, the risk of a hematuria evaluation was less than the incidence of life-threatening lesions discovered as a result of the evaluation. Asymptomatic hematuria, whether gross or microscopic, is a significant finding and warrants evaluation from a risk-benefit and cost-effectiveness standpoint.

Do urine dipsticks reliably predict microhematuria? The bloody truth!

Some literature has cast doubt on the reliability of urine dipsticks in the search for microhematuria. In our study, 2,000 urine dipsticks (two brands) were tested on urine samples containing 0, 0 to 5, 5 to 10, 10 to 20, and 20 to 50 red blood cells per high-power field. The same samples were retested four hours later and the same sticks were tested after four months of aging. Variables controlled for included observer, lighting, performance according to package insert, pH, specific gravity, white blood cells, ascorbic acid, protein, age of dipstick, and exposure of urine to povidine or cleaning solutions. Results obtained using both N-Multistix and Chemstrip 9 urine dipsticks correlated closely with the degree of hematuria. Overall sensitivity was 100%, and specificity was 99.3%. We conclude that these urine dipsticks are reliable and are not affected when tested on urine four hours after void, and that Chemstrips 9 are much more reliable than are N-Multistix if aged in air for four months.

The urinalysis: a critical appraisal

The urinalysis, an inexpensive office test, is often performed unnecessarily. Improved chemical testing using reagent strips obviates the need for routine microscopy in many cases. More information is needed to make specific recommendations on the use of the routine urinalysis as a screening procedure.

The significance of asymptomatic microhematuria in men 50 or more years old: findings of a home screening study using urinary dipsticks

In an ongoing home screening study 231 men 50 or more years old without known causes of hematuria have tested their urine each week with a chemical reagent strip for the presence of blood. After 3 months of testing 23 patients have had hematuria at least once. Of these men 5 have had urinary cancers and 5 have had other serious underlying diseases requiring immediate treatment. In only 3 of these 10 men (only 1 with cancer) did hematuria occur in more than a third of the testings or on subsequent microscopic urinalysis. The degree of hematuria was unrelated to the seriousness of its cause. We conclude that in this population hematuria occurs so intermittently that when found on routine urinalysis, regardless of quantity, serious underlying pathological conditions must be ruled out aggressively. Furthermore, regular hematuria home testing appears to offer promise as an economical means to detect urinary cancers and other serious diseases in asymptomatic men 50 or more years old.

Haematuria following a marathon run: source and significance

Urine specimens were obtained from 98 runners before and immediately after running a half (21 km) or full (42 km) marathon. Specimens were examined for the presence of proteinuria, haematuria and whether the erythrocytes were normomorphic or dysmorphic as determined by phase contrast microscopy. Proteinuria occurred in 35% of those running the half and 69% running the full marathon. Haematuria with or without proteinuria occurred in 21% running the half and 22% running the full marathon. In runners with haematuria, dysmorphic erythrocytes were found in 30% of the half and 81% of the full marathon group. No urinary abnormalities were found on repeat examination 4 to 12 weeks after the run. These results suggest that non-glomerular bleeding, possibly from bladder contusions, predominates at shorter distances. With greater distances glomerular bleeding occurs. These abnormalities disappear with rest and do not appear to signify underlying urinary tract disease.

Importance of occult haematuria found at screening

A retrospective study of the results of dipstick testing and microscopical examination of urine from 10 050 men undergoing health screening showed a prevalence of occult haematuria of 2.5%. Those patients with occult haematuria who were resident in the United Kingdom and registered with a general practitioner were identified and a questionnaire sent to their general practitioners asking what further investigations had been performed. The response rate was 92% (152/165 inquiries). Fifty nine general practitioners (39%) had not instigated any investigations. Among the 76 patients who underwent some further investigations abnormalities were found in 21 (28%); and among those fully investigated by examination of midstream urine, intravenous urography, and cystoscopy abnormalities were found in 12(50%). These included bladder neoplasms (two; one in a patient aged 37), epithelial dysplasia (one), staghorn calculi (one), and chronic reflux nephropathy (one). It is proposed that occult haematuria should be fully investigated regardless of the age of the patient.