Objectives Stability of concentrations of urinary stone-related metabolites was analyzed from samples of recurrent urinary stone formers to assess necessity and effectiveness of urine acidification during collection and storage.Methods First-morning urine was collected from 20 adult calcium-stone forming patients at Tomas Bata Hospital in the Czech Republic. Urine samples were analyzed for calcium, magnesium, inorganic phosphate, uric acid, sodium, potassium, chloride, citrate, oxalate, and urine particles. The single-voided specimens were collected without acidification, after which they were divided into three groups for storage: samples without acidification ("NON"), acidification before storage ("PRE"), or acidification after storage ("POST"). The analyses were conducted on the day of arrival (day 0, "baseline"), or after storage for 2 or 7 days at room temperature. The maximum permissible difference (MPD) was defined as +/- 20 % from the baseline.Results The urine concentrations of all stone-related metabolites remained within the 20 % MPD limits in NON and POST samples after 2 days, except for calcium in NON sample of one patient, and oxalate of three patients and citrate of one patient in POST samples. In PRE samples, stability failed in urine samples for oxalate of three patients, and for uric acid of four patients after 2 days. Failures in stability often correlated with high baseline concentrations of those metabolites in urine.Conclusions Detailed procedures are needed to collect urine specimens for analysis of urinary stone-related metabolites, considering both patient safety and stability of those metabolites. We recommend specific preservation steps.

DOI original paper: 10.1515/cclm-2024-0070 Background The EFLM Task and Finish Group Urinalysis has updated the ECLM European Urinalysis Guidelines (2000) on urinalysis and urine bacterial culture, to improve accuracy of these examinations in European clinical laboratories, and to support diagnostic industry to develop new technologies. Recommendations Graded recommendations were built in the following areas: Medical needs and test requisition Strategies of urine testing are described to patients with complicated or uncomplicated urinary tract infection (UTI), and high or low-risk to kidney disease. Specimen collection Patient preparation, and urine collection are supported with two quality indicators: contamination rate (cultures), and density of urine (chemistry, particles). Chemistry Measurements of both urine albumin and α1-microglobulin are recommended for sensitive detection of kidney disease in high-risk patients. Performance specifications are given for urine protein measurements and quality control of multiproperty strip tests. Particles Procedures for microscopy are reviewed for diagnostic urine particles, including urine bacteria. Technologies in automated particle counting and visual microscopy are updated with advice how to verify new instruments with the reference microscopy. Bacteriology Chromogenic agar is recommended as primary medium in urine cultures. Limits of significant growth are reviewed, with an optimised workflow for routine specimens, using leukocyturia to reduce less important antimicrobial susceptibility testing. Automation in bacteriology is encouraged to shorten turn-around times. Matrix assisted laser desorption ionization time-of-flight mass spectrometry is applicable for rapid identification of uropathogens. Aerococcus urinae, A. sanguinicola and Actinotignum schaalii are taken into the list of uropathogens. A reference examination procedure was developed for urine bacterial cultures.

OBJECTIVES:We evaluated the performance of a novel flow cell morphology analyzer AUTION EYE AI-4510 for counting particles in urine. METHODS:Analytical performance was assessed according to the EFLM European Urinalysis Guideline 2023. Trueness was compared by analyzing 1.012 fresh urine samples with the AUTION EYE AI-4510 (ARKRAY, Inc., Kyoto, Japan) against phase-contrast visual microscopy. Poisson statistics were utilized in assessment of imprecision of particle counts both with quality control material and patient specimens. RESULTS:Relative imprecision against theoretical Poisson imprecision, R(CV), was estimated to be 1.1 for red blood cells (RBC), 1.0 for white blood cells (WBC), 0.9 for squamous epithelial cells (SEC) and 1.1 for bacteria. The agreement with visual microscopy (Cohen's weighted kappa) was 0.93 for RBC, 0.95 for WBC, 0.90 for SEC, 0.79 for non-squamous epithelial cells (NSEC), 0.67 for combined casts, 0.90 for crystals and 0.88 for bacteria. No clinically significant bias was observed. Limits of quantitation at CV=30 % reached 4 × 106/L for RBC and 5 × 106/L for WBC. Differentiation of urinary crystals was improved as compared to previous data on digital cuvette imaging. CONCLUSIONS:The ARKRAY AUTION EYE AI-4510 provided a desirable imprecision, met the criteria for linearity, LoQ and carry-over, and showed an optimum comparison to visual microscopy for RBC, WBC, SEC and crystals as defined in the EFLM European Urinalysis Guideline 2023. The identification of kidney damage is recommended to be improved by using user-defined review rules. Performance of bacteria counting needs to be confirmed against urine bacterial cultures.

Die EFLM Task and Finish Group Urinalysis hat die ECLM European Urinalysis Guideline aus dem Jahr 2000 zur Urinanalyse und Urinbakterienkultur für Patient:innen mit Harnwegsinfektionen und mit unterschiedlichem Risiko für Nierenerkrankungen aktualisiert. Die Leitlinie unterstützt medizinisch begründete und wirtschaftlich ausgewogene Laborprozesse unter Berücksichtigung der Anforderungen der DIN EN ISO 15189:2022 sowie die Diagnostikindustrie bei Qualitätsspezifikationen für neue Technologien.

BACKGROUND:The EFLM Task and Finish Group Urinalysis has updated the ECLM European Urinalysis Guidelines (2000) on urinalysis and urine bacterial culture, to improve accuracy of these examinations in European clinical laboratories, and to support diagnostic industry to develop new technologies. RECOMMENDATIONS:Graded recommendations were built in the following areas. MEDICAL NEEDS AND TEST REQUISITION:Strategies of urine testing are described to patients with complicated or uncomplicated urinary tract infection (UTI), and high or low-risk to kidney disease. SPECIMEN COLLECTION:Patient preparation, and urine collection are supported with two quality indicators: contamination rate (cultures), and density of urine (chemistry, particles). CHEMISTRY:Measurements of both urine albumin and α1-microglobulin are recommended for sensitive detection of kidney disease in high-risk patients. Performance specifications are given for urine protein measurements and quality control of multiproperty strip tests. PARTICLES:Procedures for microscopy are reviewed for diagnostic urine particles, including urine bacteria. Technologies in automated particle counting and visual microscopy are updated with advice how to verify new instruments with the reference microscopy. BACTERIOLOGY:Chromogenic agar is recommended as primary medium in urine cultures. Limits of significant growth are reviewed, with an optimised workflow for routine specimens, using leukocyturia to reduce less important antimicrobial susceptibility testing. Automation in bacteriology is encouraged to shorten turn-around times. Matrix assisted laser desorption ionization time-of-flight mass spectrometry is applicable for rapid identification of uropathogens. Aerococcus urinae, A. sanguinicola and Actinotignum schaalii are taken into the list of uropathogens. A reference examination procedure was developed for urine bacterial cultures.

Abstract Measurements on clinical chemistry analysers must be verified to demonstrate applicability to their intended clinical use. We verified the performance of measurements on the Siemens Atellica® Solution chemistry analysers against the clinically acceptable analytical performance specifications, CAAPS, including the component of intra-individual biological variation, CVI . The relative standard uncertainty of measurement, i.e. analytical variation, CVA , was estimated for six example measurands, haemoglobin A1c in whole blood (B-HbA1c), albumin in urine (U-Alb), and the following measurands in plasma: sodium (P-Na), pancreatic amylase (P-AmylP), low-density lipoprotein cholesterol (P-LDL-C), and creatinine (P-Crea). Experimental CVA was calculated from single-instrument imprecision using control samples, variation between measurements on parallel instruments, and estimation of bias with pooled patient specimens. Each obtained CVA was compared with previously developed CAAPS. The calculated CVA was 1.4% for B-HbA1c (CAAPS 1.9% for single diagnostic testing, CAAPS 2.0% for monitoring after duplicate tests; IFCC units), 10.9% for U-Alb (CAAPS 44.9%), 1.2% for P-Na (CAAPS 0.6%, after triplicate testing 1.5%), 8.2% for P-AmylP (CAAPS 22.9%). The CVA was 4.9% for P-LDL-C (CAAPS for cardiovascular risk stratification 4.9% after four replicates), and 4.2% for P-Crea (CAAPS 8.0%). Three of the six measurands fulfilled the estimated clinical need. Results from P-Na measurements indicate a general need for improving the P-Na assays for emergency patients. It is necessary to consider CVI when creating diagnostic targets for laboratory tests, as emphasised by the CAAPS estimates of B-HbA1c and P-LDL-C.

Background: The biological (CVI), preanalytical (CVPRE), and analytical variation (CVA) are inherent to clinical laboratory testing and consequently, interpretation of clinical test results.Methods: The sum of the CVI, CVPRE, and CVA, called diagnostic variation (CVD), was used to derive clinically acceptable analytical performance specifications (CAAPS) for clinical chemistry measurands. The reference change concept was applied to clinically significant differences (CD) between two measurements, with the formula CD = z*& RADIC;2* CVD. CD for six measurands were sought from international guidelines. The CAAPS were calculated by subtracting variances of CVI and CVPRE from CVD. Modified formulae were applied to consider statistical power (1-beta) and repeated measurements. Results: The obtained CAAPS were 44.9% for urine albumin, 0.6% for plasma sodium, 22.9% for plasma pancreatic amylase, and 8.0% for plasma creatinine (z = 3, alpha = 2.5%, 1-beta = 85%). For blood HbA1c and plasma low-density lipoprotein cholesterol, replicate measurements were necessary to reach CAAPS for patient monitoring. The derived CAAPS were compared with analytical performance specifications, APS, based on biological variation.Conclusions: The CAAPS models pose a new tool for assessing APS in a clinical laboratory. Their usability depends on the relevance of CD limits, required statistical power and the feasibility of repeated measurements.

Background and aims: We assessed the possibility to rule out negative urine cultures by counting with UriSed 3 PRO (77 Elektmnika, Hungary) at Helsinki and Uusimaa Hospital District. Materials and methods: Bacteria counting of the UriSed 3 PRO automated microscope was verified with reference phase contrast microscopy against growth in culture. After acceptance into routine, results of bacteria and leukocyte counting from 56 426 specimens with eight UriSed 3 PRO instruments were compared against results from parallel samples cultured on chromogenic agar. Laboratory data including preanalytical details were accessed through the regional database of the Helsinki and Uusimaa Hospital District. Results: A combined sensitivity of 87-92% and a negative predictive value of 90-96% with a specificity of 54-50% was reached, depending on criteria. Preanalytical data (incubation time in bladder) combined with the way of urine collection would improve these figures if reliable. Conclusions: Complex patient populations, regional logistics and data interfases, and economics related to increased costs of additional particle counts against costs of screening cultures of all samples, did not support adaptation of a screening process of urine cultures. This conclusion was made locally, and may not be valid elsewhere.

BACKGROUND AND AIMS:Ten UriSed 3 PRO automated microscopes (77 Elektronika, Hungary) were verified for nine HUSLAB laboratories with 160 000 annual urine samples. MATERIALS AND METHODS:Particle counting of the primary UriSed 3 PRO instrument (77 Elektronika, Hungary) was verified against reference visual microscopy with 463 urine specimens, and against urine culture on chromogenic agar plates with parallel 396 specimens. Nine secondary instruments were compared pairwise with the primary instrument. RESULTS:Relative imprecisions compared to Poisson distribution, R(CV), were estimated to be 1.0 for white blood cell (WBC) and 1.5 for red blood cell (RBC) counts, respectively. Spearman's correlations against visual microscopy were rS = 0.94 for WBC, rS = 0.87 for RBC, and rS = 0.82 for squamous epithelial cell (SEC) counts. Agreement with visual microscopy (Cohen's weighted kappa) was 0.94 for WBC, 0.89 for RBC, 0.88 for SEC, 0.59 for combined casts, and 0.49 for non-squamous epithelial cells (NEC). Bacteria were detected with a sensitivity of 90% and specificity of 39 against culture at 107 CFB/L (104 CFU/mL). Created flagging limits allowed automated reporting for 70-75% of patient results. CONCLUSIONS:UriSed 3 PRO instruments were adopted into routine use after acceptance of the verification.