Urine Specimens from Pregnant and Nonpregnant Women Inhibitory to Amplification of \u3cem\u3eChlamydia trachomatis\u3c/em\u3e Nucleic Acid by PCR, Ligase Chain Reaction, and Transcription-Mediated Amplification: Identification of Urinary Substances Associated with Inhibition and Removal of Inhibitory Activity

The presence of endogenous amplification inhibitors in urine may produce false-negative results for the detection of Chlamydia trachomatis nucleic acids by tests such as PCR, ligase chain reaction (LCR), and transcription-mediated amplification (TMA). Consecutive urine specimens from 101 pregnant women and 287 nonpregnant women submitted for urinalysis were processed for C. trachomatis detection. Aliquots were spiked with the equivalent of one C. trachomatis elementary body and were tested by three commercial assays: AMPLICOR CT/NG, Chlamydia LCX, and Chlamydia TMA. The prevalence of inhibitors resulting in complete inhibition of amplification was 4.9% for PCR, 2.6% for LCR, and 7.5% for TMA. In addition, all three assays were partially inhibited by additional urine specimens. Only PCR was more often inhibited by urine from pregnant women than by urine from nonpregnant women (9.9 versus 3.1%; P = 0.011). A complete urinalysis including dipstick and a microscopic examination was performed. Logistic regression analysis revealed that the following substances were associated with amplification inhibition: beta-human chorionic gonadotropin (odd ratio [OR], 3.3) and crystals (OR, 3.3) for PCR, nitrites for LCR (OR, 14.4), and hemoglobin (OR, 3.3), nitrites (OR, 3.3), and crystals (OR, 3.3) for TMA. Aliquots of each inhibitory urine specimen were stored at 4 and -70°C and a dilution of 1:10 (84% for PCR, 100% for LCR, and 92% for TMA). Five urine specimens (three for PCR and two for TMA) required phenol-chloroform extraction to remove inhibitors. The results indicate that the prevalence of nucleic acid amplification inhibitors in female urine is different for each technology, that this prevalence may be predicted by the presence of urinary factors, and that storage and dilution remove most of the inhibitors

Enhanced Urinalysis as a Screening Test for Urinary Tract Infection in Children Aged One Month to Twelve Years

OBJECTIVE: Comparison of enhanced urinalysis and routine urine analysis in screening for UTI in children against positive urine culture. METHODS: Descriptive study conducted by involving 205 children aged above one year to twelve years attending OPD or got admitted, with symptoms/signs suggestive of UTI in tertiary care hospital. Urine samples were obtained by age appropriate methods ( catheterization, MSCCU); results of enhanced urinalysis (urine WBC count/mm3 plus Gram-stain both in uncentrifuged sample) and routine urine analysis (WBC and bacteria per high-power-field in centrifuged sample) compared with urine culture results( positive urine results defined as 5x104CFU/ml and >105CFU/ml for two methods of sampling) for each sample. RESULTS: The enhanced UA showed significantly greater sensitivity and PPV (84.2% and 96% respectively ;95% confidence interval) than the routine urine analysis(54.4% and 88.6% respectively).the specificity doesn’t show much difference among the two methods(98.6% and 97.3% respectively).when Gram stain of uncentrifuged urine alone considered shows higher sensitivity (89.5%),and specificity( 93.2%). CONCLUSION: Both screening test cannot identify all children with UTI. Sample for Urine culture should be obtained from all children with suspicious of UTI, can begin presumptive treatment in case of enhanced urinalysis positivity. Gram stain of urine can be used as a screening tool either as single or in combination in primary care level with limited resources

Performance Evaluation of Automated Urine Analyzers: Laura XL

Urinalysis is the third most used diagnostic screening test in clinical practice. Manual urine analysis is labor-intensive and requires experienced staff for accurate results and interpretation. New-generation automated urianalysers have been introduced with microscopic analysis. The aim of this study was to evaluate the results of LauraXL, automated Urine Analyzer and validate it with UF 4000 Sysmex and manual method. Method: A cross-sectional study was conducted on 107 urine samples. Laura XL works on image-based microscopy, whereas UF 4000 works on the principle of flow cytometry. Epithelial cells (EC), red blood cells (RBC), white blood cells (WBC), crystals, cast, and yeast from both machines were compared with manual microscopy. Results: The degree of concordance was analyzed. UF4000 showed greater agreement than Laura for WBC, EC, and Crystals, kappa as 0.420, 0.238, and 0.437 respectively (p <0.0001.) Yeast showed substantial agreement with kappa 0.650(UF 4000) and 0.643 (LauraXL). The agreement of Laura with Manual was greater than UF4000 for RBC (kappa 0.360 and p<0.0001). UF4000 revealed a sensitivity of >95% for WBC, EC, CAST, Crystal, and Yeast. Similar results were observed for Laura except for Crystal (sensitivity: 81%). Conclusion: Both automatic urine analyzers exhibited comparable performances and strongly correlated with manual microscopy. While manual urinalysis remains critical for diagnosis, automated systems offer enhanced efficiency, accuracy, and reliability, making them indispensable in modern clinical laboratories

Comparison of the Performance of the IDEXX SediVue Dx® with Manual Microscopy for Detection of Cells and Crystals in Urine Sediments

Microscopic evaluation of urine sediments is underutilized in veterinary clinics. The IDEXX SediVue Dx® Urine Sediment Analyzer (SediVue) has been recently introduced for automated analysis of canine and feline urine. The objective of this study was to compare the performance of the SediVue with manual microscopy for detecting clinically significant numbers of cells and crystals. Five hundred thirty-four urine samples (81% canine, 19% feline) were evaluated. For SediVue analysis (1.0.0.0 and 1.0.1.3), 165 μL of well-mixed, uncentrifuged urine was pipetted into a disposable cartridge. Seventy high-resolution images were captured and processed using a veterinary-specific neural network algorithm. For manual microscopy, urine was centrifuged to obtain sediment. Red blood cells (RBC), white blood cells (WBC), squamous epithelial cells (EPI), and non-squamous epithelial cells (NEC) were quantified by averaging the number of cells in 10 high power fields (HPF), while struvite crystals (TRI) and calcium oxalate dihydrate crystals (CaOxd) were placed into a semi-quantitative category. For clinical significance, a threshold of ≥ 5/HPF was used for RBC and WBC, while a threshold of ≥ 1/HPF was used for epithelial cells and crystals. Using these thresholds, sensitivity and specificity of the SediVue for formed element detection were determined as compared to manual microscopy. The sensitivity of the SediVue (1.0.1.3) was good for detection of RBC, WBC, and TRI; moderate for CaOxd; fair for NEC; and poor for EPI. Specificity was excellent for EPI and CaOxd; good for RBC, WBC, and NEC; and moderate for TRI. The newer software version (1.0.1.3) displayed improved sensitivity but decreased specificity for most elements compared to the older version (1.0.0.0). Performance of the Sedivue was overall similar for canine versus feline samples as well as between fresh and stored samples. Precision of the instrument was acceptable. The SediVue Dx provides diagnostically useful information regarding the presence of clinically significant numbers of formed elements in canine and feline urine and should increase the number of complete urinalyses performed in private practice. Performance is best for RBC, WBC, TRI, and CaOxd, while improvement is needed for epithelial cells. Further software development should continue to enhance accuracy of formed element detection

Preanalytical requirements of urinalysis

Urine may be a waste product, but it contains an enormous amount of information. Well-standardized procedures for collection, transport, sample preparation and analysis should become the basis of an effective diagnostic strategy for urinalysis. As reproducibility of urinalysis has been greatly improved due to recent technological progress, preanalytical requirements of urinalysis have gained importance and have become stricter. Since the patients themselves often sample urine specimens, urinalysis is very susceptible to preanalytical issues. Various sampling methods and inappropriate specimen transport can cause important preanalytical errors. The use of preservatives may be helpful for particular analytes. Unfortunately, a universal preservative that allows a complete urinalysis does not (yet) exist. The preanalytical aspects are also of major importance for newer applications (e.g. metabolomics). The present review deals with the current preanalytical problems and requirements for the most common urinary analytes

Missed urinary tract infection in patients with chronic recalcitrant LUTS and recurrent cystitis

Background: MSU culture and Urinary dipsticks as a diagnostic method for urinary infection (UTI) are discredited despite commonly used to exclude UTI in patients with lower urinary tract symptoms (LUTS). The phenotype of painful LUTS has been recast as Interstitial Cystitis (IC) or Bladder Pains Syndrome (BPS) because infection has been excluded on the evidence of these methods. Given that these all-important tests have been found insensitive and misleading, there is justification in re-examining IC/BPS to ascertain whether we have been mistaken. I studied patients with “Chronic recalcitrant bladder pain and recurrent cystitis” (abbreviated “painful LUTS”) who had been diagnosed with IC/PBS in order to re-assess their pathophysiology.// Aim: I characterised these patients using the scientific method of consilience, which scrutinised them from unrelated perspectives. These studies implied that infection was a most probable aetiological factor. Therefore, I moved on to test infection as a causal factor using Pearl’s three rungs of causation: Correlation, intervention and the counterfactual.// Methods: Data on quality of life and disease experience were obtained. Symptoms and pathophysiological variables in 146 patients presenting with painful LUTS were studied. To achieve Pearl’s specifications, an observational study studied intervention and a cross-over study analysed the counter factual of arbitrary treatment cessation. The evolution of treatment of these patients, using first generation, narrow spectrum urinary agents in protracted courses is reported. Since protracted antibiotic exposure is feared as a cause of antimicrobial resistance (AMR), I measured this in order to round off my findings// Results: The consilience studies incriminated UTI in the aetiology of painful LUTS. It is also clear that the patients suffer terribly, and this is aggravated by professional scepticism catalysed by a misinterpretation of urinalysis data. Antibiotic intervention demonstrated a regression in all disease indicators but there was resurgence of symptoms and signs during trials without treatment. The data on AMR demonstrated a rise in resistance in response to a first prescription without this increasing with persistence of the antibiotic regimen.// Conclusion: These data imply that IC/BPS (painful LUTS) is caused by a treatable urinary tract infection and are sufficient to merit a RCT. Whilst, treatment requires protracted exposure to antibiotics, my data on AMR amongst these patients is surprisingly reassuring. This requires further exploration. Contemporaneous to this thesis, other have published definitive data that refute urine culture and dipstick analysis./