Routine admission urinalysis examination in pediatric patients: a poor value.

The urinalysis has long been considered an important screening test for hospitalized children. The value of the admission urinalyses, required by hospital bylaws, was assessed for detecting urinary tract disease in children admitted to a day-care unit or impatient medical or surgical services during the months of June and November 1987. Of 2695 admissions, urinalyses were considered essential for diagnosis or therapy in 543 patients (excluded from analysis). In the remaining 2152 patients eligible for screening, urinalyses were obtained in 145 (30%) of day-care unit and 587 (35%) of inpatient admissions. The results of 149 (20%) of screening urinalyses were abnormal (23% abnormal in inpatient and 10% abnormal in day-care unit admissions). The numbers of urinalyses with abnormal results were similar in surgical and medical admissions and between the months of June and November. Pyuria (90 patients) and hematuria (66 patients) were the most common abnormalities in initial urinalyses. Follow-up urinalyses and other diagnostic studies were obtained in 38% of patients with abnormal admission urinalysis results. In subsequent urinalyses, 58% showed persistent abnormalities; however, most subsequent abnormal results were not pursued with additional tests. Urinary tract infections were diagnosed in 6 patients. No other additional diagnoses were determined. The cost of initial urinalyses and subsequent diagnostic studies in these 732 patients during the 2 months was $23,465. The cost per diagnosis of urinary infection was $3911. It is concluded that when hospital bylaws require routine urinalyses at the time of admission, this requirement is frequently ignored and, in addition, abnormal results are often unappreciated or not pursued.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of bedside testing options for the critical care unit.

Bedside testing offers a unique opportunity for earlier and more specific diagnosis, faster and more frequent monitoring, and the opportunity to improve patient care and reduce hospital costs. However, if abused it may not improve patient care and may increase hospital costs. In the future, more clinical studies will need to be performed to determine which tests are cost-effective.

Routine postcesarean urine culture. A cost-effectiveness analysis.

Paired urinalysis and urine culture reports on 302 postcesarean patients were studied to determine whether screening postcesarean urinalyses could be useful in predicting positive urine cultures. A positive culture was predicted with a specificity of 97.5% and a sensitivity of 90.4%. The screening urinalysis had a positive predictive value of 73.1% and a negative predictive value of 99.3%. Routine postcesarean urine cultures were not found to be cost effective.

Changing physician test ordering in a university hospital. An intervention of physician participation, explicit criteria, and feedback.

To decrease inappropriate test ordering by medical house staff in a university hospital, we examined the feasibility of an intervention that involved physicians in developing explicit criteria for ordering four specific tests and incorporated feedback of tests ordered. We implemented a time series design with measures at 12 and six months before, during, and three weeks after the intervention. During the intervention, orders for initial or admission chest roentgenograms decreased by 22% and repeated orders for routine urinalyses, chest roentgenograms, and leukocyte differential counts decreased by 23%, 30%, and 46%, respectively, compared with the six-month preintervention period. Orders for prothrombin time and/or partial thromboplastin time did not fall. After the intervention, most test ordering remained at the intervention level. These preliminary results suggest that this intervention may be effective and not overly costly.

Automation and work-simplification in the urinalysis laboratory. A pilgrim's progress.

The evolution of the modern clinical laboratory has produced a gap between medical/scientific competence on the one hand and management skills on the other. Physician-managers need both sets of competencies. Concepts of operations management and cost accounting shape criteria for strategic decisions in technology improvement programs. Automation and work-simplification are key strategies for improving cost performance in clinical laboratories.

Routine admission laboratory testing for general medical patients.

We evaluated the usefulness of commonly ordered routine admission laboratory tests in 301 patients admitted consecutively to the internal medicine wards of a university teaching hospital. Using a consensus analysis approach, three Department of Medicine faculty members reviewed the charts of admitted patients to determine the impact of the test results on patient care. The evaluated tests were the urinalysis, hematocrit, white blood cell count, platelet count, six-factor automated multiple analysis (serum sodium, potassium, chloride, bicarbonate, glucose, and blood urea nitrogen), prothrombin time, partial thromboplastin time, chest x-ray, and electrocardiogram. Forty-five percent of the 3,684 tests were ordered for patients without recognizable medical indications. Twelve percent of these routine tests were abnormal, 5% led to additional laboratory testing, but only 0.5% led to change in the treatment of patients. We conclude that the impact of routine admission laboratory testing on patient care is very small and that there is little justification for ordering tests solely because of hospital admission.

Assessment of the pathogenetic role of physical exercise in renal stone formation.

The effects of moderate physical exercise (performed on a bicycle ergometer to 70-75% of maximum oxygen consumption) without fluid replenishment on urinary chemistries and crystallization of kidney stone-forming substances were compared to those of rest in six normal subjects. Moderate physical exercise significantly decreased urinary pH [from 6.35 +/- 0.32 (+/-SD) to 5.79 +/- 0.33; P less than 0.05] and citrate [from 121.1 +/- 63.5 to 88.2 +/- 44.4 mg/6-h period from initiation of physical exercise; P less than 0.05 (630 +/- 331 to 459 +/- 231 mumol/6 h)], owing to induced metabolic acidosis. The total renal excretion of stone-forming constituents decreased [for example, calcium from 31.2 +/- 15.8 to 21.4 +/- 6.5 mg/6 h (0.8 +/- 0.4 to 0.5 +/- 0.2 mmol/6 h), phosphorus from 155 +/- 42 to 127 +/- 27 mg/6 h (5.01 +/- 1.4 to 4.1 +/- 0.9 mmol/6 h), and uric acid from 172 +/- 60 to 117 +/- 13 mg/6 h (1.0 +/- 0.4 to 0.7 +/- 0.1 mmol/6 h), each P less than 0.05], probably due to extracellular volume contraction (from sweating) and enhanced renal tubular reabsorption. However, the urinary concentration of stone-forming constituents significantly increased during and after moderate exercise because of the fall in urinary volume from 847 +/- 312 to 290 +/- 36 ml/6 h (P less than 0.01). Thus, urinary calcium oxalate saturation increased significantly from 2.62- to 6.68-fold saturation (P less than 0.01). The urinary undissociated uric acid concentration significantly rose [from 31.6 +/- 24.8 to 125.7 +/- 60.3 mg/L (0.19 +/- 0.15 to 0.76 +/- 0.36 mmol/L; P less than 0.01)], due to higher total uric acid concentration and reduced urinary pH. The saturation of calcium phosphate (brushite) did not change significantly, because the rise in urinary calcium concentration was compensated for by reduced phosphate dissociation (from lower urinary pH). The propensity for spontaneous precipitation of calcium oxalate was greater after exercise, as less soluble oxalate was required to elicit nucleation of calcium oxalate [58.0 +/- 21.2 to 49.0 +/- 16.4 mg/L (644 +/- 236 to 544 +/- 182 mumol/L); P less than 0.05]. The results suggest that moderate physical exercise, without increased fluid intake to compensate for excessive sweating, may cause the crystallization of uric acid and calcium oxalate in urine and may enhance the risk of the formation of renal stones composed of these salts.

Valoración de la función del túbulo renal por la estimación de la excreción de agua y solutos / Measurement of kidney tubules function by water and solutes excretion

Se estudiaron 106 personas adultas de ambos sexos; 21 normales, 33 diabéticos sin evidencias de nefropatía y 52 portadores de nefropatía. Los pacientes con nefropatía se dividieron en tres grupos según el tipo: I) Nefropatía glomerular vascular, 15 observaciones: II) Nefropatía túbulo intersticial (NTI) o nefropatía obstructiva, 17 observaciones; III) Nefropatía diabética; 20 observaciones. Se determinó: osmolaridad urinaria (Uosm), clearence osmolar (Cosm), reabsorción tubular de agua (Fe H2O), fracción excretada osmolar (Fe osm), fracción excretada de sodio (Fe Na), fracción excretada de potasio (Fe K) y clearence de creatinina (Ccr). Las determinaciones se realizaron luego de ayuno de ocho horas y en 31 observaciones luego de administrar vasopresina por vía subcutánea. En los pacientes con Ccr disminuido de los grupos I y II se comprobó: disminución de Uosm, Cosm, TeH2O y aumento de Fe H2O, Fe K. Se encontraron netas diferencias entre los grupos. La Fe Na se encontró normal en las glomerulopatías y aumentada en las nefrotías túbulointersticiales. La variación de las FeK Fe H2O y Fe osm fueron significativamente mayores en las nefropatías túbulointersticiales. La administración de vasopresina no determinó diferencias en los resultados

Subcutaneous and intranasal administration of 1-deamino-8-d-arginine vasopressin in the assessment of renal concentration capacity.

Maximum urine concentration capacity was studied in healthy adults using different routes and doses of administration of 1-deamino-8-d-arginine vasopressin (DDAVP)-desmopressin. Plasma levels of DDAVP showed a dose-dependent increase after the subcutaneous but not after the intranasal administration. The effect on urine osmolality was similar but more prolonged after the subcutaneous as compared to the intranasal route. We conclude that subcutaneous injection is a simple and reliable way of administering DDAVP. A dose of 4 micrograms in adults is optimum diagnostically and it corresponds to 20-40 micrograms administered intranasally.

Is automated urinalysis in your laboratory's future?

Examination of the urine, possibly the earliest diagnostic test in medicine, has only recently benefited from automation; one previous twentieth-century advance was substitution of specific reagents for earlier nonspecific chemical tests that were subject to interferences. In the mid-1970s, semiautomated urinalysis instruments were developed to read and record chemical test reactions used in manual urinalysis. Further, in 1984 the first instrument coupling automated intelligent microscopy (AIM) with a dipstick reader became available, fully automating both the biochemical screening and microscopic examination of urine specimens. This assessment describes AIM, as embodied in the Yellow IRIS instrument, and also discusses alternative strategies that laboratorians are developing to improve the cost effectiveness of conventional urinalysis.

Can the cost savings of eliminating urine microscopy in biochemically negative urines be extended to the pediatric population?

The authors determined the value of performing urine microscopy on biochemically negative urine specimens in a pediatric population. Four reactions of the Chemstrip-9TM (Biodynamics, Inc., Indianapolis, IN) were used as biochemical indicators, namely, protein, occult blood, leukocyte esterase, and nitrite. Out of 1,016 urine specimens thus studied, 310 were true positive. Eleven specimens reacted biochemically in the absence of significant microscopic findings (false positive), 668 specimens were negative by the Chemstrip-9 and were either negative microscopically or had less than five white blood cells (WBCs) per high power field (HPF) and were considered true negatives. Twenty-seven specimens had negative biochemical indicators, in spite of positive microscopy; of these specimens, only seven had more than ten WBCs per HPF, 17 had five to ten WBCs per HPF, and three had five to ten red blood cells per HPF. The sensitivity of the four parameters for predicting significant microscopy of urinary sediment is 91% and the specificity is 98%. The predictive value of a negative result is 96.1%, and that of a positive result is 96.5%. The authors therefore conclude that urine microscopy is unnecessary in biochemically negative urine specimens from pediatric patients who are asymptomatic for urinary tract disease.

Relationship of beliefs and behavior in test ordering.

Understanding the reasons physicians order diagnostic tests may be useful in designing strategies to promote cost-effective practice and helpful in developing appropriate endpoints for evaluations of new diagnostic technologies. Testing by 27 private office physicians for 324 hypertensive patients was examined and the doctors were surveyed for their beliefs about appropriate levels of use for common tests, how they compared with other doctors in frequency of use, and their reasons for ordering tests. Beliefs about appropriate levels of testing were correlated with actual use (0.45 to 0.63, Pearson). Usage also correlated with beliefs about relative ordering patterns. Annual testing charges incurred by physicians who believed they ordered tests "more frequently" than average were higher than those who believed they ordered tests "less frequently" than average ($122 +/- $46 versus $51 +/- $15, p less than 0.05). Reasons for ordering tests were (in order of importance): establishing a baseline, assessing prognosis, reassuring patients, and helping with treatment decisions. These results suggest that "high usage" physicians may know who they are; and therefore strategies of feedback to modify behavior should be designed to do more than educate physicians about their own utilization. Second, evaluations of technology must consider more than contributions to immediate treatment decisions.

Urinalysis.

When properly performed and interpreted, urinalysis is one of the most useful tests available to the emergency physician. This article reviews procedures for urine collection and analysis, emphasizing inexpensive and noninvasive chemical, macroscopic, and microscopic techniques.

Performance of a urine-screening protocol.

The performance of a urinalysis protocol using screening Chemstrip-9 dipstick analysis with selective sediment microscopy and culture is reviewed. Sediment microscopy performed on urine samples positive for leukocyte esterase, nitrite, protein, or blood, or when specifically ordered (15% of urinalyses) was reduced by 57.1%. Protocol urine culture performed when more than 5 WBC/high-powered field (HPF), more than 10 bacteria/HPF, or yeasts were found on sediment microscopy or with a positive nitrite test was done for 9.8%. Urine culture was specifically ordered for another 13.6%. Percent significant bacteriuria (greater than or equal to 10(5) colony-forming units/mL) was higher for protocol-generated cultures (37.1%) versus ordered cultures (17.2%). For urinalyses with ordered cultures, the protocol would have detected 89.8% of cases with significant bacteriuria. The protocol has facilitated detection of significant bacteriuria with good acceptance by clinicians. Cost savings achieved by reduction of sediment microscopy was partly off-set by some increase in urine cultures performed.

Evaluation of HPLC column performance for clinical studies.

Several C18 HPLC columns, varying in column length as well as packing material diameter, were used to separate mixtures of biochemical compounds in standards and in various physiological fluids. The column performances were compared both qualitatively and quantitatively. Factors investigated included efficiency, resolution, selectivity, column effect on peak height, temperature effects, cost per analysis, and analysis times. Column lifetime was also examined. The results were used to evaluate the suitability of the various columns for use in the chromatographic analysis of physiological samples.