Abbreviated Urine Collection Compared With 24-Hour Urine Collection for Measuring Creatinine Clearance in Adult Critically Ill Patients: A Systematic Review.

OBJECTIVE: To evaluate the accuracy of abbreviated urine collection (≤12 hours) compared with 24-hour urine collection for measuring creatinine clearance (CrCl) in critically ill adult patients. DATA SOURCES: We searched PubMed, Embase, Web of Science, Google Scholar, and ProQuest Dissertations and Thesis Global; screened reference lists of included studies; and contacted the authors when needed. English studies only were considered with no restriction on dates. STUDY SELECTION AND DATA EXTRACTION: After duplicate removal, 2 reviewers screened titles/abstracts, reviewed full-text articles, and extracted data independently. Studies that compared abbreviated versus 24-hour urine collection for measuring CrCl were included. We assessed the risk of bias using the QUADAS-2 tool. We extracted correlation coefficients, mean prediction errors (ME)-as a measure of bias, and root mean squared prediction errors (RMSE)-as a measure of precision. DATA SYNTHESIS: Five studies were included, comprising 528 adult critically ill adults from surgical, medical, and trauma intensive care units (ICUs). Three studies had high risk of bias, and 2 had low risk. The studies evaluated different durations of urine collection, including 30-minute, 2-hour, 4-hour, 6-hour, and 12-hour. Mean 24-hour CrCl ranged from 57 mL/min/1.73 m2 to 103 mL/min. Abbreviated urine collection led to CrCl that correlated well with the 24-hour measured CrCl (correlation coefficient ranged from 0.8 to 0.95). Mean prediction error ranged from 5 mL/min/1.73 m2 to 16 mL/min (from 8% to 25% of the 24-hour CrCl). Root mean squared prediction error calculated from 1 study was 30.5 mL/min/1.73 m2. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Abbreviated urine collection is used to measure CrCl for renal drug dosing in critically ill patients, but its accuracy is not well-established. CONCLUSIONS: Abbreviated urine collection may overestimate CrCl compared with 24-hour urine collection. Larger, well-conducted studies are needed to evaluate the accuracy of CrCl measured using different durations of urine collection in critically ill patients.

Correcting for Plasma Aldosterone Improves the Accuracy of Repeated Timed Urine Sampling for Estimation of Dietary Sodium Intake.

INTRODUCTION: Long-term sodium balance studies show that sodium can be temporarily stored and released in tissues, mediated by circaseptan rhythms of aldosterone and cortisol. This complicates the reliability of a single 24-h urine collection to estimate individual sodium intake. We investigated whether repeated timed urine collection with and without correction for plasma aldosterone is a more accurate alternative for estimating daily sodium intake. METHODS: We conducted a post hoc analysis of a metabolic ward study in which 16 healthy male adults consumed a diet with a fixed sodium content (50 or 200 mmol/day) for 7 days. Each day, urine was collected in 4 intervals (7:00-13:00 h, 13:00-19:00 h, 19:00-23:00 h, and 23:00-07:00 h). Plasma aldosterone was measured at 6:30 h, 12:30 h, and 18:30 h. Sodium intakes were estimated by various formulas using 3 timed urines of day 5-7. RESULTS: During a 200-mmol daily sodium intake, sodium intake estimates based on three repeated timed urine samples and the Toft equation differed 10 [IQR: 3-14], 8 [6-19], 36 [16-49], and 20 [10-43] mmol from the actual intake for intervals 7:00-13:00 h, 13:00-19:00 h, 19:00-23:00 h, 23:00-7:00 h, respectively. These measurements did not significantly differ from a single 24-h urine (20 [12-55] mmol). During a 50-mmol daily sodium intake, repeated timed urine collection performed worse than a single 24-h urine collection. On both diets, correction for plasma aldosterone increased accuracy and sodium intake estimates were significantly more accurate than a single 24-h urine. CONCLUSION: In a controlled environment, repeated timed urine collection corrected for plasma aldosterone is more accurate than a single 24-h urine collection.

Spot urinary sodium in CKD patients: correlation with 24h-excretion and evaluation of commonly used prediction equations.

BACKGROUND: Salt intake in CKD patients can affect cardiovascular risk and kidney disease progression. Twenty-four hour (24h) urine collections are often used to investigate salt metabolism but are cumbersome to perform. We assessed urinary sodium (U-Na) concentration in spot urine samples and investigated the correlation with 24h U-Na excretion and concentration in CKD patients under nephrological care. Further, we studied the role of CKD stage and diuretics and evaluated the performance of commonly used formulas for the prediction of 24h U-Na excretion from spot urine samples. METHODS: One hundred eight patients of the German Chronic Kidney Disease (GCKD) study were included. Each participant collected a 24h urine and two spot urine samples within the same period. The first spot urine sample (AM) was part of the second morning urine. The second urine sample was collected before dinner (PM). Patients were advised to take their medication as usual without changing dietary habits. U-Na concentrations in the two spot urine samples and their average ((AM + PM)/2) were correlated with U-Na concentration and total Na excretion in the 24h urine collections. Correlations were subsequently studied after stratification by CKD stage and diuretic intake. The usefulness of three commonly applied equations to estimate 24h U-Na excretion from spot urine samples (Kawasaki, Tanaka and Intersalt) was determined using Bland-Altman plots, analyses of sensitivity, specificity, as well as positive (PPV) and negative predictive values (NPV). RESULTS: Participants (42 women, 66 men) were on average (± SD) 62.2 (± 11.9) years old, with a mean serum creatinine of 1.6 (± 0.5) mg/dl. 95% had arterial hypertension, 37% diabetes mellitus and 55% were on diuretics. The best correlation with 24h U-Na total excretion was found for the PM spot U-Na sample. We also found strong correlations when comparing spot and 24h urine U-Na concentration. Correction of spot U-Na for U-creatinine did not improve strength of correlations. Neither CKD stage, nor intake of diuretics had significant impact on these correlations. All examined formulas revealed a significant mean bias. The lowest mean bias and the strongest correlation between estimated and measured U-Na excretion in 24h were obtained using the Tanaka-formula. Also, application of the Tanaka-formula with PM U-Na provided best sensitivity, specificity, PPV and NPV to estimate U-Na excretion > 4g/d corresponding to a salt consumption > 10g/d. CONCLUSION: U-Na concentration of spot urine samples correlated with 24h U-Na excretion especially when PM spot U-Na was used. However, correlation coefficients were relatively low. Neither CKD stage nor intake of diuretics appeared to have an influence on these correlations. There was a significant bias for all tested formulas with the Tanaka-formula providing the strongest correlation with measured 24h U-Na excretion. In summary, using spot urine samples together with the Tanaka-formula in epidemiological studies appears feasible to determine associations between approximate salt intake and outcomes in CKD patients. However, the usefulness of spot-urine samples to guide and monitor salt consumption in individual patients remains limited.

Practice variation in urine collection methods among pre-toilet trained children with suspected urinary tract infection: a systematic review.

BACKGROUND: Urinary tract infections (UTIs) are a common cause of acute illness among infants and young children. There are numerous methods for collecting urine in children who are not toilet trained. This review examined practice variation in the urine collection methods for diagnosing UTI in non-toilet-trained children. METHODS: A systematic review was completed by searching MEDLINE (Ovid), Embase (Ovid), CENTRAL (Ovid), PsycInfo (Ovid), CINAHL (EBSCO), and JBI (Ovid) from January 1, 2000 until October 9, 2021 and updated on May 24, 2023. Studies were included if they were conducted in an acute care facility, examined pre-toilet trained children, and compared one urine collection method with another for relevant health care outcomes (such as length of stay in an ED, or re-visits or readmissions to the ED) or provider satisfaction. Two independent reviewers screened the identified articles independently, and those included in the final analysis were assessed for quality and bias using the Newcastle-Ottawa Scale. RESULTS: Overall, 2535 articles were reviewed and 8 studies with a total of 728 children were included in the final analysis. Seven studies investigated the primary outcome of interest, practice variation in urine collection methods to diagnose a UTI. The seven studies that investigated novel methods of urine collection concluded that there were improved health care outcomes compared to conventional methods. Novel methods include emerging methods that are not captured yet captured in clinical practice guidelines including the use of ultrasound guidance to aid existing techniques. Three studies which investigated healthcare provider satisfaction found preference to novel methods of urine collection. CONCLUSIONS: There is significant practice variation in the urine collection methods within and between countries. Further research is needed to better examine practice variation among clinicians and adherence to national organizations and societies guidelines. PROSPERO registration number CRD42021267754.

The impact of urine collection method on canine urinary microbiota detection: a cross-sectional study.

BACKGROUND: The urinary tract harbors unique microbial communities that play important roles in urogenital health and disease. Dogs naturally suffer from several of the same urological disorders as humans (e.g., urinary tract infections, neoplasia, urolithiasis) and represent a valuable translational model for studying the role of urinary microbiota in various disease states. Urine collection technique represents a critical component of urinary microbiota research study design. However, the impact of collection method on the characterization of the canine urinary microbiota remains unknown. Therefore, the objective of this study was to determine whether urine collection technique alters the microbial populations detected in canine urine samples. Urine was collected from asymptomatic dogs by both cystocentesis and midstream voiding. Microbial DNA was isolated from each sample and submitted for amplicon sequencing of the V4 region of the bacterial 16 S rRNA gene, followed by analyses to compare microbial diversity and composition between urine collection techniques. RESULTS: Samples collected via midstream voiding exhibited significantly higher sequence read counts (P = .036) and observed richness (P = .0024) than cystocentesis urine. Bray Curtis and Unweighted UniFrac measures of beta diversity showed distinct differences in microbial composition by collection method (P = .0050, R2 = 0.06 and P = .010, R2 = 0.07, respectively). Seven taxa were identified as differentially abundant between groups. Pasteurellaceae, Haemophilus, Friedmanniella, two variants of Streptococcus, and Fusobacterium were over-represented in voided urine, while a greater abundance of Burkholderia-Caballeronia-Paraburkholderia characterized cystocentesis samples. Analyses were performed at five thresholds for minimum sequence depth and using three data normalization strategies to validate results; patterns of alpha and beta diversity remained consistent regardless of minimum read count requirements or normalization method. CONCLUSION: Microbial composition differs in canine urine samples collected via cystocentesis as compared to those collected via midstream voiding. Future researchers should select a single urine collection method based on the biological question of interest when designing canine urinary microbiota studies. Additionally, the authors suggest caution when interpreting results across studies that did not utilize identical urine collection methods.

Optimising urinary catecholamine metabolite diagnostics for neuroblastoma.

INTRODUCTION: The analysis of urinary catecholamine metabolites is a cornerstone of neuroblastoma diagnostics. Currently, there is no consensus regarding the sampling method, and variable combinations of catecholamine metabolites are being used. We investigated if spot urine samples can be reliably used for analysis of a panel of catecholamine metabolites for the diagnosis of neuroblastoma. METHODS: Twenty-four-hour urine or spot urine samples were collected from patients with and without neuroblastoma at diagnosis. Homovanillic acid (HVA), vanillylmandelic acid (VMA), dopamine, 3-methoxytyramine, norepinephrine, normetanephrine, epinephrine and metanephrine were measured by high-performance liquid chromatography coupled with fluorescence detection (HPLC-FD) and/or ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-MS/MS). RESULTS: Catecholamine metabolite levels were measured in urine samples of 400 neuroblastoma patients (24-hour urine, n = 234; spot urine, n = 166) and 571 controls (all spot urine). Excretion levels of catecholamine metabolites and the diagnostic sensitivity for each metabolite were similar in 24-hour urine and spot urine samples (p > .08 and >.27 for all metabolites). The area under the receiver-operating-characteristic curve (AUC) of the panel containing all eight catecholamine metabolites was significantly higher compared to that of only HVA and VMA (AUC = 0.952 vs. 0.920, p = .02). No differences were observed in metabolite levels between the two analysis methods. CONCLUSION: Catecholamine metabolites in spot urine and 24-hour urine resulted in similar diagnostic sensitivities. The Catecholamine Working Group recommends the implementation of spot urine as standard of care. The panel of eight catecholamine metabolites has superior diagnostic accuracy over VMA and HVA.

Validation of spot urine in estimating 24-h urinary sodium, potassium and sodium-to-potassium ratio during three different sodium diets in healthy adults.

PURPOSE: To evaluate the validity of spot urine assay methods in estimating the 24-h urinary sodium, potassium and sodium-to-potassium ratio during three different sodium diets. MATERIALS AND METHODS: Twelve healthy volunteers were asked to adhere to 3 dietary sodium targets (3.3-5.0g/day,<3.3 g/day and >5.0 g/day) for three consecutive weeks and to measure salt excretion daily in spot urine samples using a self-monitoring device. On day 7 of each week, 24-h urine was collected to compare measured with estimated 24-h salt excretion (by the Kawasaki, Tanaka and INTERSALT equations). RESULTS: Correlation coefficients relating measured and estimated 24-h sodium excretion were low and not significant for Kawasaki and INTERSALT and moderate for the Tanaka equation (τ 0.56-0.64,p<.05). Bland-Altman plots showed considerable differences between estimated and measured sodium excretion across all salt diets. Over 40% of the participants showed an absolute difference between measured and estimated 24-h sodium of more than 1000 mg/day. The correlation coefficients between 24-h and spot Na/K ratio were 0.67, 0.94 and 0.85(p<.05), and mean differences were 0.59, 0.06 and 0.48 for the intermediate, low and high sodium diets, respectively. CONCLUSION: These findings do not support estimation of individual 24-h salt excretion from spot urine by the Kawasaki, Tanaka, or INTERSALT formula. Plain language summaryAccurate monitoring of salt intake is essential to improve BP control. At present, measurement of sodium and potassium excretion in multiple non-consecutive 24-h urinary collections is considered the gold standard for measuring dietary sodium intake. However, this method is burdensome, time-consuming and error prone.Therefore, we assessed and compared the validity of three formula-based approaches to estimate 24-h urinary sodium and potassium excretion and the Na/K ratio from spot urine samples measured by a self-monitoring device under three different sodium diets using 24-h urine collections as the reference.We conclude that use of three commonly used equations that estimate 24-h urinary sodium and potassium excretion result in substantial bias, poor precision and poor accuracy and are therefore not recommended. The Na/K ratio based on multiple casual urine samples may be a useful, low-burden, low-cost alternative method to 24-h urine collection for monitoring daily salt intake.

Urine collection methods in precontinent children treated at the paediatric emergency department.

AIM: To describe the urine collection methods used in precontinent children presenting at the Paediatric Emergency Department (PED) and compare results and contamination rates. METHODS: Retrospective observational cohort study that included 1678 urine cultures collected in infants <24 months of age between January 2016 and December 2019. Urine cultures were compared based on collection technique, sex and patient age. RESULTS: In total, 60.4% of samples were collected by clean-catch urine collection (CCUC), 26.4% by urethral catheterisation (UC) and 13.2% by urine bag (UB). Contamination rates were 2.9% (95% CI 1.3, 4.4) for UC, 11.3% (95% CI 9.3, 13.2) for CCUC and 23.4% (95% CI 17.8, 29.0) for UB. Significant differences in contamination rates were found between UC and CCUC in the 6-12-month age group (1.9% [95% CI 0.0-4.0] versus 12.0% [95% CI 7.2-16.8] [p < 0.0009]), and between UC and UB for all ages. CONCLUSIONS: CCUC is the most common method for urine culture collection in infants <24 months of age at the PED in our centre. UC has the lowest contamination rates, but significant differences were only observed between CCUC and UC in the 6-12-month age group. CCUC is a non-invasive alternative for urine collection in infants.

Use of Cotton Balls in Diapers for Collection of Urine Samples Impacts the Analysis of Routine Chemistry Tests: An Evaluation of Cotton Balls, Diapers, and Chemistry Analyzers.

OBJECTIVE: To evaluate the suitability of urine samples collected with cotton balls placed into diapers for routine laboratory chemistry analyses. STUDY DESIGN: Twenty pools of residual unpreserved urine samples were separated into control and treated aliquots. The treated samples were absorbed into 2 different brands of cotton balls, wrapped in 3 different brands of diapers, and incubated at 37°C for 1 hour. The urine-soaked cotton balls were placed into a syringe and expressed via plunger depression. Urine sodium, potassium, creatinine, urea, calcium, magnesium, inorganic phosphorus, albumin, and total protein were measured on all samples on 5 automated clinical chemistry platforms: Ortho Vitros 4600, Siemens Dimension Vista 500, Beckman Coulter AU5822, Roche Cobas 6000, and Abbott Architect c8000 at 5 separate hospital laboratories. Criteria used to exclude the presence of significant effects of urine from presoaked cotton balls in a diaper on the measurement of chemistry laboratory tests were R2 >0.95, slope of 0.9-1.1, and mean bias within ±10%. RESULTS: Albumin and total protein measurements demonstrated significant negative bias in urine from both brands of presoaked cotton balls with all brands of diapers on all 5 chemistry platforms compared with the control urine. We did not observe a significant effect of presoaking urine in cotton balls in a diaper on the measurement of sodium, inorganic phosphorus, and urea. The remaining tests demonstrated significant effects when measured in urine from presoaked cotton balls and/or diapers that were specific to the chemistry analyzer platform or diaper. CONCLUSIONS: Diaper and cotton ball-based urine collection significantly impacts the measurement of several common chemistry assays.

c-fos expression in the olfactory epithelium of the East African cichlid (Haplochromis chilotes) in response to odorant exposure.

Fishes use olfaction to gain varied information vital for survival and communication. To understand biodiversity in fishes, it is important to identify what receptors individual fish use to detect specific chemical compounds. However, studies of fish olfactory receptors and their ligands are still limited to a few model organisms represented primarily by zebrafish. Here, we tested the c-fos expression of olfactory sensory neurons (OSNs) in an East African cichlid, the most diversified teleost lineage, by in situ hybridization with a c-fos riboprobe. We confirmed that microvillous neurons contributed the most to the detection of amino acids, as in other fishes. Conversely, we found that ciliated neurons contributed the most to the detection of conjugated steroids, known as pheromone candidates. We also found that V2Rs, the major receptor type in microvillous neurons, exhibited differential responsiveness to amino acids, and further suggest that the cichlid-specific duplication of V2R led to ligand differentiation by demonstrating a differential response to arginine. Finally, we established a non-lethal method to collect cichlid urine and showed how various OSNs, including V1R+ neurons, respond to male urine. This study provides an experimental basis for understanding how cichlids encode natural odours, which ultimately provides insight into how olfaction has contributed to the diversification of cichlids.

Proteinuria during pregnancy: definition, pathophysiology, methodology, and clinical significance.

Qualitative and quantitative measurement of urine protein excretion is one of the most common tests performed during pregnancy. For more than 100 years, proteinuria was necessary for the diagnosis of preeclampsia, but recent guidelines recommend that proteinuria is sufficient but not necessary for the diagnosis. Still, in clinical practice, most patients with gestational hypertension will be diagnosed as having preeclampsia based on the presence of proteinuria. Although the reference standard for measuring urinary protein excretion is a 24-hour urine collection, spot urine protein-to-creatinine ratio is a reasonable "rule-out" test for proteinuria. Urine dipstick screening for proteinuria does not provide any clinical benefit and should not be used to diagnose proteinuria. The classic cutoff cited to define proteinuria during pregnancy is a value of >300 mg/24 hours or a urine protein-to-creatinine ratio of at least 0.3. Using this cutoff, the rate of isolated proteinuria in pregnancy may reach 8%, whereas preeclampsia occurs among 3% to 8% of pregnancies. Although this threshold is widely accepted, its origin is not based on evidence on adverse pregnancy outcomes but rather on expert opinion and results of small studies. After reviewing the available data, the most important factor that influences maternal and neonatal outcome is the severity of blood pressures and presence of end organ damage, rather than the excess protein excretion. Because the management of gestational hypertension and preeclampsia without severe features is almost identical in frequency of surveillance and timing of delivery, the separation into 2 disorders is unnecessary. If the management of women with gestational hypertension with a positive assessment of proteinuria will not change, we believe that urine assessment for proteinuria is unnecessary in women who develop new-onset blood pressure at or after 20 weeks' gestation. Furthermore, we do not recommend repeated measurement of proteinuria for women with preeclampsia, the amount of proteinuria does not seem to be related to poor maternal and neonatal outcomes, and monitoring proteinuria may lead to unindicated preterm deliveries and related neonatal complications. Our current diagnosis of preeclampsia in women with chronic kidney disease may be based on a change in protein excretion, a baseline protein excretion evaluation is critical in certain conditions such as chronic hypertension, diabetes, and autoimmune or other renal disorders. The current definition of superimposed preeclampsia possesses a diagnostic dilemma, and it is unclear whether a change in the baseline proteinuria reflects another systemic disease such as preeclampsia or whether women with chronic disease such as chronic hypertension or diabetes will experience a different "normal" pattern of protein excretion during pregnancy. Finally, limited data are available regarding angiogenic and other biomarkers in women with chronic kidney disease as a potential aid in distinguishing the worsening of baseline chronic kidney disease and chronic hypertension from superimposed preeclampsia.

Accuracy of equations for predicting 24-h urinary potassium excretion from spot urine samples in Chinese children.

Accurate assessments of potassium intake in children are important for the early prevention of CVD. Currently, there is no simple approach for accurate estimation of potassium intake in children. We aim to evaluate the accuracy of 24-h urinary potassium excretion (24UKV) estimation in children using three common equations: the Kawasaki, Tanaka and Mage formulas, in a hospital-based setting. A total of 151 participants aged 5-18 years were initially enrolled, and spot urine samples were collected in the whole 24-h duration to measure the concentrations of potassium and creatinine. We calculated the mean difference, absolute and relative difference and misclassification rate between measured 24UKV and the predicted ones using Kawasaki, Tanaka and Mage formulas in 129 participants. The mean measured 24UKV was 1193·3 mg/d in our study. Mean differences between estimated and measured 24UKV were 1215·6, -14·9 and 230·3 mg/d by the Kawasaki, Tanaka and Mage formulas, respectively. All estimated 24UKV were significantly different from the measured values in all the time point (all P < 0·05), except for the predicted values from Tanaka formula using morning, afternoon and evening spot urine. The proportions with relative differences over 40 % were 87·2%, 32·5% and 47·3 % for Kawasaki, Tanaka and Mage formulas, respectively. Misclassification rates were 91·5 % for Kawasaki, 44·4 % for Tanaka and 58·9 % for Mage formula at the individual level. Our findings showed that misclassification could occur on the individual level when using Kawasaki, Tanaka and Mage formulas to estimate 24UKV from spot urine in the child population.

Urinary microbiota of women with recurrent urinary tract infection: collection and culture methods.

INTRODUCTION AND HYPOTHESIS: Many clinicians utilize standard culture of voided urine to guide treatment for women with recurrent urinary tract infections (RUTI). However, despite antibiotic treatment, symptoms may persist and events frequently recur. The cyclic nature and ineffective treatment of RUTI suggest that underlying uropathogens pass undetected because of the preferential growth of Escherichia coli. Expanded quantitative urine culture (EQUC) detects more clinically relevant microbes. The objective of this study was to assess how urine collection and culture methods influence microbial detection in RUTI patients. METHODS: This cross-sectional study enrolled symptomatic adult women with an established RUTI diagnosis. Participants contributed both midstream voided and catheterized urine specimens for culture via both standard urine culture (SUC) and EQUC. Presence and abundance of microbiota were compared between culture and collection methods. RESULTS: Forty-three symptomatic women participants (mean age 67 years) contributed specimens. Compared to SUC, EQUC detected more unique bacterial species and consistently detected more uropathogens from catheterized and voided urine specimens. For both collection methods, the most commonly detected uropathogens by EQUC were E. coli (catheterized: n = 8, voided: n = 12) and E. faecalis (catheterized: n = 7, voided: n = 17). Compared to catheterized urine samples assessed by EQUC, SUC often missed uropathogens, and culture of voided urines by either method yielded high false-positive rates. CONCLUSIONS: In women with symptomatic RUTI, SUC and assessment of voided urines have clinically relevant limitations in uropathogen detection. These results suggest that, in this population, catheterized specimens analyzed via EQUC provide clinically relevant information for appropriate diagnosis.

Dietary sodium estimation methods: accuracy and limitations of old and new methods in individuals at high cardiovascular risk.

OBJECTIVE: Accurate and easy to use methods for dietary Na intake estimation in population level are lacking. We aimed at (i) estimating the mean Na intake in the group level using a variety of dietary methods (DM) and urinary methods (UM) and correlating them with 24-h urine collection (24UCol) and (ii) improving the accuracy of the existing DM. DESIGN: The most common DM (three 24-h dietary recalls (24DR) and FFQ) and UM (24UCol and spot urine collection using common equations) were applied. To improve the existing: (i) 24DR, discretionary Na was quantified using salt-related questions or adding extra 15 % in total Na intake and (ii) FFQ, food items rich in Na and salt-related questions were added in the standard questionnaire (NaFFQ). SETTING: National and Kapodistrian University of Athens, Greece. PARTICIPANTS: Totally, 122 high cardiovascular risk subjects (56·0 ± 12·6 years; 55·7 % males). RESULTS: Mean 24 h Na excretion (24UNa) was 2810 ± 1304 mg/d. Spot urine methods overestimated the 24UNa (bias range: -1781 to -492 mg) and were moderately correlated to 24UCol (r = 0·469-0·596, P ≤ 0·01). DM underestimated the 24UNa (bias range: 877 to 1212 mg) and were weakly correlated with 24UCol. The improved DM underestimated the 24UNa (bias range: 877 to 923 mg). The NaFFQ presented the smallest bias (-290 ± 1336 mg) and the strongest correlation with 24UCol (r = 0·497, P ≤ 0·01), but wide limits of agreement in Bland-Altman plots (-2909 mg; 2329 mg), like all the other methods did. CONCLUSIONS: The existing methods exhibit poor accuracy. Further improvement of the newly developed NaFFQ could be promising for more accurate estimation of mean dietary Na intake in epidemiological studies. Additional validation studies are needed.

Reducing the urine collection rate could prevent hospital-acquired horizontal transmission of multidrug-resistant Pseudomonasaeruginosa.

INTRODUCTION: Multidrug-resistant Pseudomonas aeruginosa (MDRP) is a waterborne pathogen that occasionally causes hospital-acquired infection in immunocompromised or critically ill patients. Urine is frequently collected to evaluate renal function or to perform hormonal examinations, but the procedure involves risk due to the possibility of healthcare workers with contaminated hands. Our objective was to evaluate the association between the urine collection and hospital-acquired horizontal transmission of MDRP. METHODS: We monitored the urine collection rate from 2011 to 2017, as part of ongoing efforts to reduce the need to collect urine. The urine collection rate and the frequency of isolation of MDRP, Methicillin resistant S. aureus (MRSA) and extended spectrum ß-lactamases (ESBL)-producing E. coli were analyzed during the same period. PFGE and MLST were also performed to analyze the identity of 5 MDRP strains detected on the same ward in 2014-2015. RESULTS: The urine collection rate was dramatically decreased from 4.8% in 2011 to less than 0.5% in 2017, because the isolation rate of MDRP was significantly positively associated (RR = 1.72, 95%CI:1.03-2.85) with the urine collection rate. Isolations of MRSA and ESBL-producing E. coli showed no significant. Molecular typing showed the PFGE patterns of 3 of 5 MDRP strains were closely related as did MLST (ST17), and the remaining 2 MDRP strains had different PFGE and MLST patterns (ST14, ST655). Our data implicated the urine collection as one of the causes of hospital-acquired MDRP infections. CONCLUSIONS: We concluded that a reducing the urine collection rate could contribute to preventing hospital-acquired horizontal transmission of MDRP.

Composition of Urine Collected from Non-Stone-Forming Chinese Persons during Different Short-Term Periods of the Day.

The purpose of this study in a small group of non-stone-forming Chinese persons was to measure the levels of supersaturation with calcium oxalate and calcium phosphate and pH with the aim of confirming if any of the different short-term urine samples were better for risk evaluation than a 24-h sample. Nine normal men and 1 woman collected urine during 4 periods of the day. Period 1 between 08 and 12 h, Period 2 between 12 and 18 h, Period 3 between 18 and 22 h, and Period 4 between 22 and 08 h. Each sample was analysed for calcium, oxalate, citrate, magnesium and phosphate, and estimates of supersaturation with calcium oxalate (CaOx) and calcium phosphate (CaP) were expressed in terms of AP(CaOx) and AP(CaP) index. An estimate of the solute load of CaOx was also calculated. Urine composition for 24-h urine (Period 24) was obtained mathematically from the analysed variables. Urine composition corresponding to 14-h urine portions 22-12 h (Period 14N) and 08-22 h (Period 14 D) were calculated. The lowest pH levels were recorded in Period 1 urine. The highest level of AP(CaOx) index was recorded during Period 1, and the product AP(CaOx) index × 107 × hydrogen ion concentration was significantly higher in Period 1 urine than in 24-h urine (p = 0.02). Also, the product SL(CaOx) × 107 × hydrogen ion concentration was significantly higher in Period 1 urine (p = 0.02). Low AP (CaP) index levels were recorded in Period 4, but also in all periods following dietary loads of calcium and phosphate. With the important reservation that the analytical results were obtained from non-stone-forming persons, the conclusion is that analysis of urine samples collected between 08 and 12 h might be an alternative to 24-h urine. The risk evaluation might advantageously be expressed either in terms of the product AP(CaOx) index × 107 × hydrogen ion concentration or the product SL(CaOx) × 107 × hydrogen ion concentration.

The impact of phone counseling on urinary stone prevention.

OBJECTIVE: We compared the effect of standard office-based consultation (OC) and phone correspondences (PC) on dietary 24-h urinary parameters. METHODS: The medical record of all patients treated between January and April 2019 was reviewed. Only patients who had at least two consecutive 24-h urine collections were included. Linear and logistic regressions were used to investigate the difference between the changes in urinary parameters after OC and PC. RESULTS: Forty-three patients underwent 135 OC and 34 PC. Twenty-one received OC and PC, and 22 had only OC. Gender, age, the distance to stone clinic, the number of previous stone episodes, and baseline urinary parameters were similar between the groups. Patients who had both OC and PC had a longer follow-up time (51.7 vs 18.5 months, p < 0.0001) as well as more consults (Median 5.4 vs 2.5, p < 0.0001). Six (27%) patients who had only OC, and eight (38%) patients who had both OC and PC, experienced stone recurrence during the study period (p = 0.52). Following PC, there was a greater improvement in urine volume in comparison to OC (0.27 l/day vs -0.06 l/day, p = 0.034), but there was no difference in the absolute values after the consults between the groups. CONCLUSION: In established stone-clinic patients, PC was associated with a better adherence with follow-up. The 24-h urine results were similar between PC and OC. PC may be an effective alternative for urinary stone management.

Urine collection methods for infants under 3 months of age in clinical practice.

BACKGROUND: Methods of urine collection used in precontinent children are a controversial issue. Definitive diagnosis of urinary tract infection (UTI) requires an uncontaminated urine culture. We aimed to describe methods used to collect urine for culture in infants under 3 months of age and compare results and contamination rates. METHODS: This retrospective observational cohort study included 721 urine cultures collected from infants <3 months of age at the Hospital Universitario Infanta Sofía, Madrid, between January 2016 and December 2019. Urine cultures were compared based on collection technique, sex, and patient age. RESULTS: Median patient age was 36 days and 54.6% were male. In total, 592 (82.1%) samples were collected using clean-catch urine stimulation technique (CCUST), 77 (10.7%) by urethral catheterization (UC) and 52 (7.2%) by urine bag (UB). Positive cultures were obtained in 11.7% (95% confidence interval [CI] 9.1, 14.3) of CCUST samples and in 28.6% (95% CI 18.5, 38.7) of UC samples (p<0.001). The contamination rate was 13.7% (95% CI 10.9, 16.4] for CCUST, 23.1% (95% CI 11.6, 34.6) for UB and 5.2% (95% CI 0.2, 10.2) for UC, with statistically significant differences (p=0.007) between UB and UC collection. CONCLUSIONS: CCUST is the most commonly used method in our hospital for collecting urine in infants younger than 3 months. The contamination rate of UC is lower but not significantly different to that of CCUST. Urine collection by CCUST serves as a non-invasive alternative to UC for diagnosis of UTI in infants under 3 months of age in routine clinical practice. Graphical abstract.

Comparison of two human infant urine collection methods for measuring estrone-3-glucuronide.

OBJECTIVES: Current human infant urine collection methods for the field are problematic for the researcher and potentially uncomfortable for the infant. In this study, we compared two minimally invasive methods for collecting infant urine: organic cotton balls and filter paper. MATERIALS AND METHODS: We first collected urine from infants using the clean catch method. We then used those samples to compare the performance of filter paper and cotton ball collection protocols. We analyzed the clean catch and cotton samples using commercial estrone-3-glucuronide (E1G) kits and tried two different extraction methods for the filter paper. Using a paired t-test (n = 10), we compared clean catch and cotton samples. We also compared effect sizes within and between methods. RESULTS: We were unable to extract enough urine from the filter paper to successfully assay the samples for E1G. The paired t-test revealed a statistically significant difference between the clean catch and cotton methods (t = 2.63, p-value = 0.03). However, the effect size was small (5.91 µg/ml, n = 10, 95% CI = 3.80, 8.02) and similar to or larger than the difference seen between duplicate wells for clean catch and cotton values. DISCUSSION: While this study is limited by sample size, our results indicate that filter paper is not a field-friendly method for collecting infant urine. However, we found that organic cotton balls showed similar values to the clean catch method, and we propose this method as an alternative, minimally invasive method for study of E1G in human infant urine.

Improving Compliance with 24-H Urine Collections: Understanding Inadequacies in the Collection Process and Risk Factors for Poor Compliance.

PURPOSE OF REVIEW: The purpose of this review paper is to describe the 24-h urine collection in terms of its utility, collection process, and common problems with its acquisition. RECENT FINDINGS: Although 24-h urine collections are standard of care for high-risk stone formers, several nuances in test acquisition including inaccurate urine collections 50% of the time and poor patient compliance limit its potential utility. Compliance in obtaining 24-h urine collections has been shown to be improved in patients who have not undergone surgical treatment of urinary calculi, patients with metabolic stone disease or family history of stone disease, Caucasian ethnicity, and in those with more sedentary occupations. Studies show conflicting data of compliance regarding patient age and gender. Physicians must understand the difficulties regarding 24-h urine collections including patient compliance, variability between collections, and complexities with interpretation to best utilize this tool in guiding clinical management for the treatment of nephrolithiasis.