Assessment of urine sample collection and processing variables for extracellular vesicle-based proteomics.

Extracellular vesicles (EVs) in urine are a promising source for developing non-invasive biomarkers. However, urine concentration and content are highly variable and dynamic, and actual urine collection and handling often is nonideal. Furthermore, patients such as those with prostate diseases have challenges in sample collection due to difficulties in holding urine at designated time points. Here, we simulated the actual situation of clinical sample collection to examine the stability of EVs in urine under different circumstances, including urine collection time and temporary storage temperature, as well as daily urine sampling under different diet conditions. EVs were isolated using functionalized EVtrap magnetic beads and characterized by nanoparticle tracking analysis (NTA), western blotting, electron microscopy, and mass spectrometry (MS). EVs in urine remained relatively stable during temporary storage for 6 hours at room temperature and for 12 hours at 4 °C, while significant fluctuations were observed in EV amounts from urine samples collected at different time points from the same individuals, especially under certain diets. Sample normalization with creatinine reduced the coefficient of variation (CV) values among EV samples from 17% to approximately 6% and facilitated downstream MS analyses. Finally, based on the results, we applied them to evaluate potential biomarker panels in prostate cancer by data-independent acquisition (DIA) MS, presenting the recommendation that can facilitate biomarker discovery with nonideal handling conditions.

Assessment of baby disposable diapers application for urine collection and determination of phthalate metabolites.

The baby disposable diapers were investigated as a sampling material for urine collection and validated for the evaluation of the exposure of children to xenobiotics. Phthalate metabolites detected in urine samples were chosen as proof-of-concept analytes. For the determination of phthalate metabolites in children's urine samples, high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used. Two sampling approaches were compared, namely sterile containers and baby disposable diapers. Thirty urine samples from infants and toddlers were analyzed by both methods in parallel and the results were compared. It was found that for diaper sampling, lower concentrations of the metabolites were observed, however, the general distribution for particular metabolites remains the same for both methods. For most of the metabolites high determination coefficients were obtained, namely 0.9929 for MEHHP, 0.9836 for MMP, 0.9796 for MECPP, and 0.9784 for 2-cx-MMHP. For MEOHP the determination correlation coefficient was 0.9154, while for MBP was - 0.7771 and MEHP was - 0.5228. In general, for diaper sampling an underestimation for 2-cx-MMHP and MEOHP was observed, while for MMP diaper-based approach provides overestimation. However, the proposed procedure confirms the possibility of using baby disposable diapers as a material for the collection of urine samples for biomonitoring purposes and fast screening of phthalates exposure.

Understanding the Barriers to Preventive Pharmacological Therapy Use in Older Patients With Urinary Stone Disease.

INTRODUCTION: Despite compelling clinical trial evidence and professional society guideline recommendations, prescription rates of preventative pharmacological therapy (PPT) for urinary stone disease are low. We sought to understand how patient- and clinician-level factors contribute to the decision to prescribe PPT after an index stone event. METHODS: We identified Medicare beneficiaries with urinary stone disease who had a 24-hour urine collection processed by a central laboratory. Among the subset with a urine chemistry abnormality (ie, hypercalciuria, hypocitraturia, hyperuricosuria, or low urine pH), we determined whether PPT was prescribed within 6 months of their collection. After assigning patients to the clinicians who ordered their collection, we fit multilevel models to determine how much of the variation in PPT prescription was attributable to patient vs clinician factors. RESULTS: Of the 11,563 patients meeting inclusion criteria, 33.6% were prescribed PPT. There was nearly sevenfold variation between the treating clinician with the lowest prescription rate (11%) and the one with the highest (75%). Nineteen percent of this variation was attributable to clinician factors. After accounting for measured patient differences and clinician volume, patients had twice the odds of being prescribed PPT if they were treated by a nephrologist (odds ratio [OR], 2.15; 95% CI, 1.79-2.57) or a primary care physician (OR, 1.78; 95% CI, 1.22-2.58) compared to being treated by a urologist. CONCLUSIONS: These findings suggest that the type of clinician whom a patient sees for his stone care determines, to a large extent, whether PPT will be prescribed.

Assessment and validation of three spot urine assay methods for the estimation of 24-hour urinary sodium excretion in Chinese Tibetan adults living in the mountains.

Twenty-four-hour urine collection is the gold standard method for the evaluation of salt intake, but it is often impractical in large-scale investigations, especially in resource-poor areas. Methods for the estimation of 24-hour urinary sodium excretion (USE) using a spot urine sample have been established, but have not been validated in Chinese Tibetans. Therefore, the authors aimed to evaluate the Kawasaki, Tanaka, and the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT) formulas for the prediction of 24-hour USE in Chinese Tibetan adults. The authors analyzed the bias, correlation, agreements between estimated values and measured values, and the relative and absolute differences and misclassification at the individual level for the three methods in 323 Tibetan participants from the Ganzi Tibetan Autonomous Prefecture of Sichuan Province, China. The mean biases between the measured values and the estimated 24-hour USE using the Kawasaki, Tanaka, and INTERSALT methods were 5.4 mmol/day (95% confidence interval [CI]: 0.8-10.1 mmol/day), -40.8 mmol/day (95% CI: -44.6 to -36.9 mmol/day), and -57.1 mmol/day (95% CI: -61.9 to -52.4 mmol/day), respectively. The Pearson correlation coefficients for the relationships between the measured values and the estimated 24-hour USE were 0.43 (Kawasaki), 0.38 (Tanaka), and 0.27 (INTERSALT), respectively (all p < .01). The intraclass correlation coefficients showed similar patterns to the correlation data: 0.47 for Kawasaki, 0.40 for Tanaka, and 0.27 for INTERSALT (all p < .01). The upper and lower limits of agreement between the measured values and the estimated 24-hour USE were -92.6 and 81.8 mmol/day for the Kawasaki method, -28.5 and 110.0 mmol/day for the Tanaka method, and -28.4 and 142.7 mmol/day for the INTERSALT method. Compared with the other two methods, the percentage of individuals that were misclassified by using the Kawasaki method was 48.2%, while those for the Tanaka and INTERSAL methods was 72.1% and 75.5%, respectively. However, when an individual's salt intake was higher than 12.8 g/day, the misclassification rates of the Kawasaki, Tanaka, and INTERSALT methods were 20%, 90%, and 97.5%, respectively. Thus, the authors found that the Kawasaki equation may have performed better than the other equations at Chinese Tibetan population level assessment, but none of these equations are suitable for use or perform well at the individual level. A more accurate method of using a spot urine sample to evaluate individual 24-hour USE for Tibetans is needed.

Investigating Fluid Intake in an Underserved Community: What Factors Are Associated with Low Urine Volume on 24-Hour Urine Collection?

Background: Stone prevention is dependent on high fluid intake, with evidence that low urine volume (LUV) can promote nephrolithiasis in the absence of other metabolic abnormalities. Herein, we investigate patient-related factors associated with LUV on initial 24-hour urine collection in an underserved population. Materials and Methods: A retrospective chart review was performed of patients treated by a single surgeon for nephrolithiasis from August 2014 to January 2019. Patients who submitted 24-hour urine samples were divided into two groups based on whether their initial collection was >2 L or not. Factors associated with 24-hour urine volume were analyzed using bivariate and multivariate analyses. As a secondary outcome, we investigated factors associated with corrected 24-hour urine volume on repeat 24-hour urine collection. Results: Two hundred eight patients (45.1%) submitted 24-hour urine collections, 63.9% (133/208) of which demonstrated a urine volume of <2 L. LUV was more common in female patients (77.1% vs 49.5%; p = 0.001) and patients with no insurance and Medicaid (no insurance [100%] vs Medicaid [74.1%] vs Medicare/private [58.6%]; p = 0.02). Female gender and insurance status were independent predictors of LUV in the multivariable analysis. Seventeen of 43 patients (39.5%) with LUV who provided a subsequent collection were able to correct their urine volume. Patients who improved their LUV were older (58.5 vs 45.9 years, p = 0.0149) and more likely to have surgical intervention for their kidney stones (94.1% vs 53.8%, p = 0.006). In our multivariable analysis, surgical intervention was associated with correcting urine volume. Conclusions: Female patients and those with no insurance or Medicaid were more likely to have LUV on an initial 24-hour urine collection. Further research into barriers to fluid intake is important for these two groups, along with directed patient education on strategies for increasing fluid intake.

Are individual analyses of multiple short urine collections throughout the 24 hours superior to a standard 24-hour urine collection in precipitation risk assessment of healthy subjects?

PURPOSE: The commonly used 24-hour collection technique has been the mainstay of diagnosis for supersaturation but has some certain limitations. Hence, superiority of multiple short urine collections as a new alternative in precipitation risk assessment was assessed compared to the standard 24-hour urine collection among healthy subjects. MATERIALS AND METHODS: Individual urine samples of 26 healthy subjects were acquired every 2 to 3 hours throughout the 24 hours. Urine samples were obtained and the time and volume of each sample were recorded. Urinary constituents involved in precipitation including, sodium-potassium, chloride, calcium, phosphate, citrate, magnesium, urea, creatinine and pH were measured. A simulated 24-hour collection was recalculated by the totalling of all shorter urine collections volume and urinary constituents excretions throughout the day. RESULTS: Urine pH, urine creatinine and precipitation rate had a significantly lower values in 24-hours urine collection compared to one individual value of multiple urine collections by -0.769 (P < .0001), -7.305 (P < .0001), and - 12.838 (P < .0001), respectively. However, calcium (2.697, P < .0001), citrate (3.54, P < .0001), total phosphate (19.961, P < .0001) and total creatinine (9.579, P < .0001) had statistically significantly higher values in the 24-hours urine collection compared to individual value of multiple urine collections. CONCLUSION: Based on the results, individual analysis of multiple shorter urine collections throughout the day improves the ability of identifying supersaturation points, precipitation risk zones and may potentially improve risk assessment compared to the 24-hour urine collection method.

Community and individual iodine status assessment in premenopausal women in Shanxi, China: Repeated spot urine versus 24-hour urine.

BACKGROUND AND OBJECTIVES: Urinary iodine is an essential index of iodine nutrition evaluation. To establish the number of repeated spot urine collections necessary to reflect individual iodine status over 2 months and assess its feasibility to serve as an independent indicator of individual iodine status. METHODS AND STUDY DESIGN: We performed a longitudinal, 2-months study from May to June in 2015 of 23 apparently healthy Chinese women aged 18 to 44 (32±9) y. Spot urine samples were collected on any two days of the week, and 24-h urine samples were collected once every 6 days. RESULTS: 368 spot urine and 230 24-h urine samples were analysed. The median urinary iodine concentration (UIC) was 140.5 (75.2, 246.9) µg/L. The estimated 24-h urinary iodine excretion (24-h UIE) values from spot urine samples and measured 24-h UIE values from 24-h urine samples were 348±240 µg/24h and 330±216 µg/24h (p=0.003), respectively. Irrespective of the urinary iodine method, the intra- individual coefficient of variation (CV%) was lower than the inter-individual CV%. Bland-Altman analysis revealed differences between spot urine and 24-h urine. When the precision ranges with 95% confidence were ±15%, ±20%, ±25% or 30%, the number of an individual's spot urine samples required were 30, 16, 11 or 8, respectively. CONCLUSIONS: Repeated spot urine is not a feasible way to assess recent individual iodine intake. The development of a multi-indicator system could provide an acceptable individual evaluation index of iodine status.

Mejora de las variaciones en la ecografía vesical Evaluación del volumen de orina residual posmiccional en obstrucción moderada de la salida de la vejiga / Improving Variations in Bladder Ultrasound Assessment of Post-Void Residual Urine Volume in Moderate Bladder Outlet Obstruction

Objectives: This study aimed to assess the accuracy of post-void residual (PVR) urine volume measurements in patients with moderate bladder outlet obstruction. Materials and Methods: This prospective observational study was conducted between January and December 2019. The inclusion criteria were male patients with symptoms of moderate bladder outlet obstruction. On the other hand, patients with a history of diabetes, symptoms of urinary tract infection, and positive urine for pyuria, as well as patients using medications, such as diuretics, alphablockers, and anticholinergic drugs, were excluded. The patients were asked to drink 1000 mL of water one to two hours before the initial ultrasound scan. Pre-void bladder capacity was measured, followed by a post-void ultrasound for residual urine volume measurement at three intervals: immediately after voiding, 15-20 minutes after the first void, and one week later with an empty bladder. Assessment of per-void capacity was carried out, based on the patient's subjective sensation of bladder fullness (a strong desire to void). Results: A total of 78 male patients, with the mean age of 60 years, were included in this study (27 cases in group I; 37 cases in group II; and 14 cases in group III). The mean PVR volume was 92 mL in the first measurement, 62 mL in the second measurement, and 60 mL in the third measurement. Significant differences were found between the first and second PVR measurements and between the first and third PVR measurements (P<0.05). However, no significant difference was found between the second and third PVR measurements (P=0.107). On the other hand, significant differences were found between groups I and II and between groups I and III (P<0.05) in the three PVR measurements. Nevertheless, there was no significant difference between groups II and III in the three PVR measurements (P=0.204, 0.56, and 0.487 for the first, second, and third PVR measurements, respectively). Conclusion: A bladder ultrasound must be performed and interpreted carefully to avoid further unnecessary medications, investigations, or procedures. We recommend a second PVR measurement in patients with bladder outlet obstruction. Also, it is suggested to conduct similar studies in different conditions to confirm our findings.

Assessment and validation of spot urine in estimating the 24-h urinary sodium, potassium, and sodium/potassium ratio in Chinese adults.

The commonly used methods of estimating the 24-h urinary sodium (UNa) and urinary potassium (UK) from spot urine (SU) are the Kawasaki method (K-method), INTERSALT method (I-method), and Tanaka method (T-method), but the method that is suitable for use in the general Chinese population is still uncertain. We aimed to assess and validate these methods in estimating the 24-h UNa and UK using SU samples in Chinese adults. We studied 1428 individuals aged 18-69 years using SU and 24-h urine samples. For the K-method, I-method, and T-method, the Pearson correlation coefficients of the 24-h UNa were 0.35, 0.35, and 0.33 (all p < 0.01), and the intraclass correlation coefficients (ICC) were 0.34, 0.26, and 0.26 (all p < 0.01), respectively. The estimated 24-h UK using the K-method and T-method had correlation coefficients of 0.36 and 0.39 (all p < 0.01) and ICCs of 0.31 and 0.27 (all p < 0.01). The mean bias for the K-method in estimating the 24-h UNa and UK were the least biased among these methods. The bias between the 24-h urine Na/K ratio and the spot urinary Na/K ratio by the Bland-Altman method was -0.22. These methods for estimating the 24-h UNa and UK from SU were inadequate at the population level in Zhejiang Province, although the K-method showed the least bias among these methods. The spot urine Na/K ratio may be a useful and alternative method for 24-h urine collection for the estimation of the urinary Na/K ratio in the Chinese population.

A systematic review and meta-analysis of 24-h urinary output of children and adolescents: impact on the assessment of iodine status using urinary biomarkers.

PURPOSE: Urinary iodine concentration (UIC (µg/ml) from spot urine samples collected from school-aged children is used to determine the iodine status of populations. Some studies further extrapolate UIC to represent daily iodine intake, based on the assumption that children pass approximately 1 L urine over 24-h, but this has never been assessed in population studies. Therefore, the present review aimed to collate and produce an estimate of the average 24-h urine volume of children and adolescents (> 1 year and < 19 years) from published studies. METHODS: EBSCOHOST and EMBASE databases were searched to identify studies which reported the mean 24-h urinary volume of healthy children (> 1 year and < 19 years). The overall mean (95% CI) estimate of 24-h urine volume was determined using a random effects model, broken down by age group. RESULTS: Of the 44 studies identified, a meta-analysis of 27 studies, with at least one criterion for assessing the completeness of urine collections, indicated that the mean urine volume of 2-19 year olds was 773 (654, 893) (95% CI) mL/24-h. When broken down by age group, mean (95% CI) 24-h urine volume was 531 mL/day (454, 607) for 2-5 year olds, 771 mL/day (734, 808) for 6-12 year olds, and 1067 mL/day (855, 1279) for 13-19 year olds. CONCLUSIONS: These results demonstrate that the average urine volume of children aged 2-12 years is less than 1 L, therefore, misclassification of iodine intakes may occur when urine volumes fall below or above 1 L. Future studies utilizing spot urine samples to assess iodine status should consider this when extrapolating UIC to represent iodine intakes of a population.

Liquid gold: the cost-effectiveness of urine sample collection methods for young precontinent children.

BACKGROUND: Urinary tract infection (UTI) is a common childhood infection. Many febrile children require a urine sample to diagnose or exclude UTI. Collecting urine from young children can be time-consuming, unsuccessful or contaminated. Cost-effectiveness of each collection method in the emergency department is unknown. OBJECTIVE: To determine the cost-effectiveness of urine collection methods for precontinent children. METHODS: A cost-effectiveness analysis was conducted comparing non-invasive (urine bag, clean catch and 5 min voiding stimulation for clean catch) and invasive (catheterisation and suprapubic aspirate (SPA)) collection methods, for children aged 0-24 months in the emergency department. Costs included equipment, staff time and hospital bed occupancy. If initial collection attempts were unsuccessful subsequent collection using catheterisation was assumed. The final outcome was a definitive sample incorporating progressive dipstick, culture and contamination results. Average costs and outcomes were calculated for initial collection attempts and obtaining a definitive sample. One-way and probabilistic sensitivity analyses were performed. RESULTS: For initial collection attempts, catheterisation had the lowest cost per successful collection (GBP£25.98) compared with SPA (£37.80), voiding stimulation (£41.32), clean catch (£52.84) and urine bag (£92.60). For definitive collection, catheterisation had the lowest cost per definitive sample (£49.39) compared with SPA (£51.84), voiding stimulation (£52.25), clean catch (£64.82) and urine bag (£112.28). Time occupying a hospital bed was the most significant determinant of cost. CONCLUSION: Catheterisation is the most cost-effective urine collection method, and voiding stimulation is the most cost-effective non-invasive method. Urine bags are the most expensive method. Although clinical factors influence choice of method, considering cost-effectiveness for this common procedure has potential for significant aggregate savings.

Health Risks for Sanitation Service Workers along a Container-Based Urine Collection System and Resource Recovery Value Chain.

Container-based sanitation (CBS) within a comprehensive service system value chain offers a low-cost sanitation option with potential for revenue generation but may increase microbial health risks to sanitation service workers. This study assessed occupational exposure to rotavirus and Shigella spp. during CBS urine collection and subsequent struvite fertilizer production in eThekwini, South Africa. Primary data included high resolution sequences of hand-object contacts from annotated video and measurement of fecal contamination from urine and surfaces likely to be contacted. A stochastic model incorporated chronological surface contacts, pathogen concentrations in urine, and literature data on transfer efficiencies of pathogens to model pathogen concentrations on hands and risk of infection from hand-to-mouth contacts. The probability of infection was highest from exposure to rotavirus during urine collection (∼10-1) and struvite production (∼10-2), though risks from Shigella spp. during urine collection (∼10-3) and struvite production (∼10-4) were non-negligible. Notably, risk of infection was higher during urine collection than during struvite production due to contact with contaminated urine transport containers. In the scale-up of CBS, disinfection of urine transport containers is expected to reduce pathogen transmission. Exposure data from this study can be used to evaluate the effectiveness of measures to protect sanitation service workers.

The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) position statement on the use of 24-hour, spot, and short duration (<24 hours) timed urine collections to assess dietary sodium intake.

The International Consortium for Quality Research on Dietary Sodium/Salt (TRUE) is a coalition of intentional and national health and scientific organizations formed because of concerns low-quality research methods were creating controversy regarding dietary salt reduction. One of the main sources of controversy is believed related to errors in estimating sodium intake with urine studies. The recommendations and positions in this manuscript were generated following a series of systematic reviews and analyses by experts in hypertension, nutrition, statistics, and dietary sodium. To assess the population's current 24-hour dietary sodium ingestion, single complete 24-hour urine samples, collected over a series of days from a representative population sample, were recommended. To accurately estimate usual dietary sodium at the individual level, at least 3 non-consecutive complete 24-hour urine collections obtained over a series of days that reflect the usual short-term variations in dietary pattern were recommended. Multiple 24-hour urine collections over several years were recommended to estimate an individual's usual long-term sodium intake. The role of single spot or short duration timed urine collections in assessing population average sodium intake requires more research. Single or multiple spot or short duration timed urine collections are not recommended for assessing an individual's sodium intake especially in relationship to health outcomes. The recommendations should be applied by scientific review committees, granting agencies, editors and journal reviewers, investigators, policymakers, and those developing and creating dietary sodium recommendations. Low-quality research on dietary sodium/salt should not be funded, conducted, or published.

The Science of Salt: Updating the evidence on global estimates of salt intake.

The Global Burden of Disease (GBD) 2010 study estimated national salt intake for 187 countries based on data available up to 2010. The purpose of this review was to identify studies that have measured salt intake in a nationally representative population using the 24-hour urine collection method since 2010, with a view to updating evidence on population salt intake globally. Studies published from January 2011 to September 2018 were searched for from MEDLINE, Scopus, and Embase databases using relevant terms. Studies that provided nationally representative estimates of salt intake among the healthy adult population based on the 24-hour urine collection were included. Measured salt intake was extracted and compared with the GBD estimates. Of the 115 identified studies assessed for eligibility, 13 studies were included: Four studies were from Europe, and one each from the United States, Canada, Benin, India, Samoa, Fiji, Barbados, Australia, and New Zealand. Mean daily salt intake ranged from 6.75 g/d in Barbados to 10.66 g/d in Portugal. Measured mean population salt intake in Italy, England, Canada, and Barbados was lower, and in Fiji, Samoa, and Benin was higher, in recent surveys compared to the GBD 2010 estimates. Despite global targets to reduce population salt intake, only 13 countries have published nationally representative salt intake data since the GBD 2010 study. In all countries, salt intake levels remain higher than the World Health Organization's recommendation, highlighting the need for additional global efforts to lower salt intake and monitor salt reduction strategies.

Urinary Cell-Free DNA: Isolation, Quantification, and Quality Assessment.

Urine cell-free DNA is an important source of diagnostic markers for different diseases (e.g., cancer and prenatal diagnosis). It is important to achieve a simple and fast protocol to maximize the recovery of DNA from urine supernatant and to assess its quality. Here we describe a simple approach from urine collection to DNA quality assessment for downstream analyses.

Quantitative measurement of urinary proteins in 2018: advantages, disadvantages, limits.

Today, there is no reference method for the measurement of urinary proteins. The difficulties are that urine is a very complex biological fluid, and that there are a high intra-and inter-individual variability in the protein excretion rate. Progress has been made during the last thirty years, but high analytical variability persists among the colorimetric or turbidimetric methods used for urinary proteins measurement.

Inequalities in healthcare access: how a man with exstrophy in rural India coped.

We report a case of a 22-year-old man with adult exstrophy. The patient made a self-made urine collection device, which helped him to lead a normal life, carrying out his routine as well as occupational activities smoothly. This patient is a prime example of inequalities in healthcare distribution in low-income and middle-income countries. He was never taken to a proper medical centre to correct his condition nor was his mother ever given proper antenatal healthcare access. His background of being a poor person from rural India highlights the problems of inequalities in healthcare access.

Pre-analytical Factors Influence Accuracy of Urine Spot Iodine Assessment in Epidemiological Surveys.

Urinary iodine concentration (UIC) is commonly used to assess iodine status of subjects in epidemiological surveys. As pre-analytical factors are an important source of measurement error and studies about this phase are scarce, our objective was to assess the influence of urine sampling conditions on UIC, i.e., whether the child ate breakfast or not, urine void rank of the day, and time span between last meal and urine collection. A nationwide, two-stage, stratified, cross-sectional study including 1560 children (6-12 years) was performed in 2012. UIC was determined by the Sandell-Kolthoff method. Pre-analytical factors were assessed from children's mothers by using a questionnaire. Association between iodine status and pre-analytical factors were adjusted for one another and socio-economic characteristics by multivariate linear and multinomial regression models (RPR: relative prevalence ratios). Skipping breakfast prior to morning urine sampling decreased UIC by 40 to 50 µg/L and the proportion of UIC < 100 µg/L was higher among children having those skipped breakfast (RPR = 3.2[1.0-10.4]). In unadjusted analyses, UIC was less among children sampled more than 5 h from their last meal. UIC decreased with rank of urine void (e.g., first vs. second, P < 0.001); also, the proportion of UIC < 100 µg/L was greater among 4th rank samples (vs. second RPR = 2.1[1.1-4.0]). Subjects' breakfast status and urine void rank should be accounted for when assessing iodine status. Providing recommendations to standardize pre-analytical factors is a key step toward improving accuracy and comparability of survey results for assessing iodine status from spot urine samples. These recommendations have to be evaluated by future research.

Impact of two-step urine culture ordering in the emergency department: a time series analysis.

BACKGROUND: Despite evidence against the use of antimicrobials for asymptomatic bacteriuria (ASB), they are frequently prescribed leading to unnecessary adverse events. Prior studies have shown that reducing unnecessary urine cultures (UCs) results in decreased antimicrobial utilisation for ASB. Emergency departments (EDs) submit the largest volume of UCs, yet efforts to limit overordering in this patient setting have had limited success. METHODS: A new two-step model of care for urine collection, using a novel UC collection container, was implemented in the ED of a large community hospital. The collection system contains a preservative allowing UCs to be held at room temperature for up to 48 hours before processing. UCs were collected by front-line staff, but only processed in the microbiology lab if requested by ED physicians after clinical assessment. RESULTS: Following implementation there was a decrease in the percentage of weekly ED visits associated with a processed UC (5.97% vs 4.68%, p<0.001), a decrease in the percentage of monthly ED visits requiring a callback for positive urine culture (1.84% to 1.12%, p<0.001) and a decrease in antimicrobial prescriptions for urinary indication among admitted patients (20.6% to 10.9%, p<0.01). There was a false omission rate of 1.35% (95% CI 0.7% to 2.2%), yet no identified cases of untreated urinary tract infection (UTI), or significant change in repeat ED visits or ED length of stay. CONCLUSIONS: Changing to two-step urine culture ordering in the ED resulted in a decrease in UCs processed, callbacks for positive results and antimicrobial use without evidence of untreated UTIs. This model of care has strong potential to improve the use of hospital resources while minimising detection and inappropriate treatment of ASB.

Assessment of dietary sodium intake using a food frequency questionnaire and 24-hour urinary sodium excretion: a systematic literature review.

Food frequency questionnaires (FFQs) are often used to assess dietary sodium intake, although 24-hour urinary excretion is the most accurate measure of intake. The authors conducted a systematic review to investigate whether FFQs are a reliable and valid way of measuring usual dietary sodium intake. Results from 18 studies are described in this review, including 16 validation studies. The methods of study design and analysis varied widely with respect to FFQ instrument, number of 24-hour urine collections collected per participant, methods used to assess completeness of urine collections, and statistical analysis. Overall, there was poor agreement between estimates from FFQ and 24-hour urine. The authors suggest a framework for validation and reporting based on a consensus statement (2004), and recommend that all FFQs used to estimate dietary sodium intake undergo validation against multiple 24-hour urine collections.