Leukocyte Esterase Test Research Articles

Predictive performance of urinalysis for urine culture results according to causative microorganisms: an integrated analysis with artificial intelligence.

Urinary tract infections (UTIs) are pervasive and prevalent in both community and hospital settings. Recent trends in the changes of the causative microorganisms in these infections could affect the effectiveness of urinalysis (UA). We aimed to evaluate the predictive performance of UA for urinary culture test results according to the causative microorganisms. In addition, UA results were integrated with artificial intelligence (AI) methods to improve the predictive power. A total of 360,376 suspected UTI patients were enrolled from two university hospitals and one commercial laboratory. To ensure broad model applicability, only a limited range of clinical data available from commercial laboratories was used in the analyses. Overall, 53,408 (14.8%) patients were identified as having a positive urine culture. Among the UA tests, the combination of leukocyte esterase and nitrite tests showed the highest area under the curve (AUROC, 0.766; 95% CI, 0.764-0.768) for predicting urine culture positivity but performed poorly for Gram-positive bacteriuria (0.642; 0.637-0.647). The application of an AI model improved the predictive power of the model for urine culture results to an AUROC of 0.872 (0.870-0.875), and the model showed superior performance metrics not only for Gram-negative bacteriuria (0.901; 0.899-0.902) but also for Gram-positive bacteriuria (0.745; 0.740-0.749) and funguria (0.872; 0.865-0.879). As the prevalence of non-Escherichia coli-caused UTIs increases, the performance of UA in predicting UTIs could be compromised. The addition of AI technologies has shown potential for improving the predictive performance of UA for urine culture results.IMPORTANCEUA had good performance in predicting urine culture results caused by Gram-negative bacteria, especially for Escherichia coli and Pseudomonas aeruginosa bacteriuria, but had limitations in predicting urine culture results caused by Gram-positive bacteria, including Streptococcus agalactiae and Enterococcus faecalis. We developed and externally validated an AI model incorporating minimal demographic information of patients (age and sex) and laboratory data for UA, complete blood count, and serum creatinine concentrations. The AI model exhibited improved performance in predicting urine culture results across all the causative microorganisms, including Gram-positive bacteria, Gram-negative bacteria, and fungi.

Neutrophil extracellular traps protect the kidney from ascending infection and are required for a positive leukocyte dipstick test.

Lower urinary tract infection (UTI) is common but only rarely complicated by pyelonephritis. However, the mechanisms preventing extension to the kidney are unclear. Here, we identified neutrophil extracellular traps (NETs) in healthy human urine that provide an antibacterial defense strategy within the urinary tract. In both in vivo murine models of UTI where uropathogenic E. coli are inoculated into the bladder and ex vivo human urine models, NETs interacted with uromodulin to form large webs that entrapped the bacteria. Peptidyl arginine deiminase 4 (PADI4) inhibition in mice blocked NETosis and resulted in progression of cystitis into pyelonephritis, suggesting that NETosis of urinary neutrophils acts to prevent bacterial ascent into the kidney. Analysis of UK Biobank data revealed that genetic variants in PADI4 that associated with increased risk of rheumatoid arthritis in multiple genome-wide association studies were consistently associated with reduced susceptibility to UTI. Last, we showed that urine dipstick testing for leukocyte esterase was negative in the presence of intact blood neutrophils but became positive when neutrophils were stimulated to NET, and this could be prevented by selective PADI4 inhibition, demonstrating that this test does not detect absolute neutrophil count, as has long been assumed, but specifically detects neutrophils that have undergone NETosis. These findings highlight the role of NETosis in preventing ascending infections in the urinary tract and improve our understanding of one of the most common clinical tests in medicine.

Evaluation of Leukocyte esterase and Nitrite dipstick tests with routine urine microscopic analysis in detecting urinary tract infections

Evaluation of Leukocyte esterase and Nitrite dipstick tests with routine urine microscopic analysis in detecting urinary tract infections

Evaluating the Predictive Efficacy of Dipstick Urinalysis for Detecting Urinary Tract Infections in Febrile Children Under Five Years of Age at Federal Medical Centre, Owerri, Imo State, Nigeria

This study aimed to assess the predictive efficacy of dipstick urinalysis in detecting urinary tract infections (UTI) among febrile children under five years of age at the Federal Medical Centre, Owerri, Imo State, Nigeria. The research involved a hospital-based descriptive cross-sectional study, analyzing the diagnostic performance of nitrite and leucocyte esterase tests on urine dipsticks. The results revealed low sensitivity but high specificity for both tests, suggesting their potential role in excluding UTI. The findings emphasize the importance of combining dipstick urinalysis with urine culture for accurate diagnosis in febrile children. Keywords: Urinary tract infections, Dipstick urinalysis, Febrile children, Nitrite, Leucocyte esterase, Diagnostic efficacy, Nigeria.

Evaluating the Predictive Efficacy of Dipstick Urinalysis for Detecting Urinary Tract Infections in Febrile Children Under Five Years of Age at Federal Medical Centre, Owerri, Imo State, Nigeria

This study aimed to assess the predictive efficacy of dipstick urinalysis in detecting urinary tract infections (UTI) among febrile children under five years of age at the Federal Medical Centre, Owerri, Imo State, Nigeria. The research involved a hospital-based descriptive cross-sectional study, analyzing the diagnostic performance of nitrite and leucocyte esterase tests on urine dipsticks. The results revealed low sensitivity but high specificity for both tests, suggesting their potential role in excluding UTI. The findings emphasize the importance of combining dipstick urinalysis with urine culture for accurate diagnosis in febrile children. Keywords: Urinary tract infections, Dipstick urinalysis, Febrile children, Nitrite, Leucocyte esterase, Diagnostic efficacy, Nigeria

A Prospective Study to Identify Asymptomatic Bacteriuria: The Causative Organisms, Antibiotic Sensitivity and its Safety in Pregnant Females

Introduction: The common procedure of urinary catheterization during childbirth may introduce bacteria that can cause urinary tract infections. Immune function is relatively compromised during pregnancy. The current study was aimed to identify antenatal patients with bacteriuria, the causative organism and its antibiotic sensitivity in patients with bacteriuria. Materials and Methods: The current prospective crosssectional study involved antenatal patients who were being admitted to the delivery room. A clean catch midstream urine sample was collected in a sterile container of which 5 to 10 mL of the sample was obtained in a separate sterile vial (container 1) for screening tests for leucocyte esterase and nitrite, and the remaining sample (container 2) was taken for routine microscopy, culture, and sensitivity. The reports were collected and tabulated, and bacteriuria was confirmed and statistically analyzed. Results: A total of 200 patients were evaluated, and 40 of them had asymptomatic bacteriuria. In this study positive leukocyte esterase test and nitrite test results were considerably higher in the cases than the controls (p < 0.05) at 10.0 and 47.5%, respectively. Escherichia coli was found to be the most prevalent bacteria in this study, followed by, Pseudomonas, Enterococcus faecalis, Candida albicans, and coagulasenegative Streptococcus and Klebsiella. Most of the E. coli isolates (100.0%) were sensitive to amikacin, a category D drug. The majority of Pseudomonas isolates (100.0%) were sensitive to colistin, a category C drug. Amongst category A drugs, Pseudomonas was sensitive to – cefoperazone-sulbactam, meropenem and piperacillin-tazobactam. Conclusion: It is a standard practice to send urine routine and microscopy test in antenatal patients. As most patients are asymptomatic, investigations are required for early diagnosis of significant bacteria like leucocyte esterase, nitrite and culture and sensitivity. This will help us to institute appropriate treatment and improve maternal and fetal outcomes.

Bedside Leukocyte Esterase Testing to aid in Diagnosing Bacterial Conjunctivitis in Children

BackgroundConjunctivitis is a frequent symptom in pediatric emergency departments; however, the etiology of conjunctivitis is difficult to clinically differentiate. ObjectiveOur study objective was to evaluate the test performance characteristics of leukocyte esterase (LE) test strips in diagnosing bacterial conjunctivitis. MethodsPatients aged from 3 months through 21 years presenting to an emergency department with symptoms of conjunctivitis were prospectively enrolled from September 2018 to March 2020. A swab of the affected eye was applied to the LE test strip and another swab was sent for culture processing. The primary outcome was the association between LE test results and eye culture results. ResultsWe enrolled 189 patients. Overall, 117 eye cultures (62%) were positive. The sensitivity and specificity of LE testing was 96% (95% CI 90–98%) and 14% (95% CI 7–25%), respectively. Positive predictive value was 64% (95% CI 57–71%) and negative predictive value was 67% (95% CI 39–87%). ConclusionsThe LE test strip had limited ability to differentiate bacterial conjunctivitis from other etiologies.

Diagnostic evaluation of leukocyte esterase reagent strip in bedside rapid diagnosis of spontaneous bacterial peritonitis in cirrhotic patients

Background: Spontaneous bacterial peritonitis (SBP) is the most common and serious infection of liver cirrhosis patients with ascites. If not intervened with early antibiotic treatment leads to high morbidity and mortality. Thus, early diagnosis and treatment of SBP are needed for survival. Leukocyte esterase reagent can aid in early diagnosis. Aims and Objectives: This study aimed to assess the diagnostic accuracy of the leukocyte esterase dipstick test for the diagnosis of SBP in resource poor settings. Materials and Methods: This cross-sectional study was conducted during August 2018–January 2019 on patients with cirrhotic liver disease and ascites in a tertiary care medical college hospital, Puducherry. All patients underwent abdominal paracentesis, and ascitic fluid was subjected to cell counts, biochemistry tests, culture, and leukocyte esterase test (Multistrix SG8- Seimens) at 120 s and graded with five levels. Grade 3 was positive (125 polymorphonuclear leukocytes [PMNL]/mL) and grade 4 (<500/mL), which exceeds the threshold for SBP (<250 PMNL/mL). Sensitivity, specificity, positive, and negative predictive value (PPV and NPV) was calculated. Results: A total of 50 ascitic fluids were analyzed. Nine out of 50 (18%), 16 (32%), and 4 (8%) were positive for cell count method, Leucocyte esterase reagent (LER) test and culture, respectively. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy for LER test were 6.25%, 91.18%, 25%, 67.39%, and 64%, respectively. Conclusion: The LER strip test is useful for SBP diagnosis in an emergency and resource poor setting. It provides good diagnostic accuracy and high NPV and it is cost effective and better bedside tool for SBP diagnosis.

Leukocyte esterase and alpha-defensin in periprosthetic joint infection: predictive quality and correlation in a prospective study

PurposePeriprosthetic joint infection (PJI) is a rare but serious complication of total joint arthroplasty (TJA). An accurate diagnosis of PJI preoperatively does not exist. Alpha-defensin (AD) is a proven and common indicator. The diagnostic marker of leukocyte esterase (LE) promises some advantages: feasibility, availability, and fast result reporting. The aim of this study was the evaluation of the predictive quality and correlation between both diagnostic tools in the diagnosis of PJI.MethodsA prospective study was conducted between April 2018 and August 2022. All patients with suspicion of PJI on hip and knee joint were included and underwent a routine and standardized joint punction. For laboratory diagnostics of AD, the synovial liquid was analyzed by ELISA. The sample was additionally applied to a LE test strip (Combur 10 Test, Roche Diagnostics, Mannheim, Germany).ResultsA total of 249 patients were examined (mean age 67.12 ± 11.89; gender distribution man/woman 139 (55.8%)/110(44.2%), hip/knee 71(28.5%)/178 (71.5%). According to EBJIS criteria, PJI was diagnosed in 54 (21.7%) patients. AD showed excellent results with an AUC of 0.930 (sensitivity/specificity 0.870/0.990). LE yielded very good results with an AUC of 0.820 (sensitivity/specificity 0.722/0.918). Both parameters showed a strong positive correlation.ConclusionLE is a rapidly available alternative in PJI diagnostics. The simultaneous determination of both markers may enhance diagnostic reliability. A routine usage may shorten the time from diagnosis to treatment of PJI.

Comparison of Enhanced and Manual Urinalysis for Detecting Urinary Tract Infections in Children

Background: Urinary tract infections (UTIs) are among the most common bacterial infections in children. Urinalysis (UA) is a beneficial test for the preliminary diagnosis of UTIs. The presence of bacteriuria in UA can be determined by either an enhanced (using uncentrifuged Gram-stained specimens) or manual (using centrifuged specimens) technique. However, the diagnostic performance of enhanced UA is not well-established in childhood UTIs. Objectives: To assess the ability of enhanced and automated urinalysis to detect UTIs in children. Methods: This cross-sectional study was conducted on 191 children with the symptoms of UTI referred to Dr. Sheikh Hospital, Mashhad, Iran, from 2018 to 2019. Standard urinalysis, enhanced urinalysis, and quantitative urine culture were performed on specimens. A positive enhanced UA test was defined as ≥ 10 white blood cells per mL of urine and the presence of any bacteria per 10 high-power microscopic fields of a Gram-stained smear. A positive manual UA test was defined as ≥ 5 white blood cells per high-power field. The results of standard and enhanced UA were compared with urine culture findings to determine the accuracy of these two methods in detecting UTIs. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for each test. Results: The results showed that the prevalence of UTI was 23%. Enhanced UA retrieved a sensitivity of 97.7%, specificity of 93.1%, PPV of 81.1%, and NPV of 99.3% for detecting UTIs. In standard UA, sensitivity, specificity, PPV, and NPV were 90.9%, 80.7%, 57.1%, and 96.6% for pyuria, 56.8%, 98.6%, 92.5%, and 88.4% for the nitrite test, 72.7%, 94.5%, 80%, and 92% for the leukocyte esterase test, respectively. Conclusions: Enhanced UA had higher sensitivity, specificity, PPV, and NPV than standard UA.

Penilaian Hasil Dipstik Urine (Nitrit Dan Leukosit Esterase) Sebagai Prediktor Bakteriuria

Bacteriuria is the leading indicator of Urinary Tract Infection (UTI), which is detected through urine culture examination. Significant bacteriuria indicates the growth of microorganisms as much as ≥ 100,000 cfu/ml in urine culture. There are drawbacks to this examination that requires a screening test with a short time and lower cost. This study aimed to determine differences in the results of nitrite and leukocyte esterase examination using a urine dipstick with urine culture as a predictor of bacteriuria. The type of research used is analytic with an experimental approach. The sample used in this study was ten samples of urine. Based on the bivariate analysis results, the p-value was 0.541, which means that there was no difference in the results of leukocyte esterase and urine culture. This indicates the presence of leukocytes in the urine can be an indication of bacteriuria. The results for the nitrite examination obtained a p-value of 0.000, which means there is a difference between the results of the nitrite examination and the results of the urine culture. This shows that the presence of nitrites in the urine cannot indicate of bacteriuria. However the data on the sensitivity and specificity of dipstick examination are still low for leukocyte esterase and urine nitrite tests. However, urine dipstick examination to detect bacteriuria and UTI is still an option for faster screening. Keywords : leukocyte esterase, nitrites, urine culture

Evaluation of the BioFire® FilmArray® Pneumonia Panel with Conventional Bacterial Culture in Conjunction with Leukocyte Esterase Test.

We evaluated the performance of the BioFire® FilmArray® Pneumonia panel (PN-panel) in detecting bacterial pathogens by comparing it to cultures and to the usefulness of the leukocyte esterase (LE) urine strip test. Between January and June 2022, a total of 67 sputum specimens were obtained from community-acquired pneumonia patients. The PN-panel and LE test were performed simultaneously with conventional cultures. The pathogen detection rates of the PN-panel and culture were 40/67 (59.7%) and 25/67 (37.3%), respectively. The concordance rate between the PN-panel and culture was high (76.9%) when the bacterial burden was high (107 copies/mL), but it was low (8.6%) when it was 104-6 copies/mL, irrespective of the sputum quality. According to the LE positivity, the overall culture positive rate and PN-panel positive rate were significantly higher among the LE-positive specimens (23/45, 31/45) than among the LE-negative specimens (2/21, 8/21). Moreover, the difference in concordance rate between the PN-panel test and culture was significant according to the LE positivity, but not the Gram stain grading. In conclusion, the PN-panel showed high concordance when the bacterial burden was high (107 copies/mL) and ancillary use of LE test will be helpful in interpreting the PN-panel results, especially when the copy number of bacterial pathogens is low.

Biomarkers for febrile urinary tract infection in children.

The current reference standard for pediatric urinary tract infection (UTI) screening, the leukocyte esterase (LE) dipstick test, has suboptimal accuracy. The objective of this study was to compare the accuracy of novel urinary biomarkers to that of the LE test. We prospectively enrolled febrile children who were evaluated for UTI based on their presenting symptoms. We compared the accuracy of urinary biomarkers to that of the test. We included 374 children (50 with UTI, 324 without UTI, ages 1-35 months) and examined 35 urinary biomarkers. The urinary biomarkers that best discriminated between febrile children with and without UTI were urinary neutrophil gelatinase-associated lipocalin (NGAL), IL-1β, CXCL1, and IL-8. Of all examined urinary biomarkers, the urinary NGAL had the highest accuracy with a sensitivity of 90% (CI: 82-98) and a specificity of 96% (CI: 93-98). Because the sensitivity of the urinary NGAL test is slightly higher than that of the LE test, it can potentially reduce missed UTI cases. Limitations of using urinary NGAL over LE include increased cost and complexity. Further investigation is warranted to determine the cost-effectiveness of urinary NGAL as a screening test for UTI.

The optimal diagnostic cut-off of WBC and PMN counts for joint aspiration in periprosthetic joint infection is 2479/µL and 67%, respectively: ICM criteria thresholds are too high.

Various organizations have published definitions for periprosthetic joint infection (PJI) with significant differences in the cut-offs of white blood cell (WBC) count and polymorphonuclear (PMN) leukocyte cells. Herein, we aim to analyze optimal cut-offs in patients which are planned to undergo a prosthesis revision and compare them with the actual published thresholds of the International Consensus Meeting (ICM) and European Bone and Joint Infection Society (EBJIS). A test kit was compiled in a monocentric prospective study, according to the ICM criteria (2018) and 2021 EBJIS criteria. The kit was implemented using: blood samples (including leukocyte count and C-reactive protein); samples for examining the synovial fluid (WBC count, PMN cell differentiation, microbiological culture for incubation over 14days, alpha-defensin ELISA laboratory test, and leukocyte-esterase test). The cut-offs for WBC and PMN counts were investigated using ROC analyses and Youden index. The ICM 2018 criteria were applied, using alpha-defensin in all cases. Patients which have to undergo a prosthesis revision were included, a pre-operative joint aspiration had been performed, and the patients had been followed up prospectively. 405 patients were examined with the compiled test kit; 100% had a complete dataset with respect to alpha-defensin; 383 patients, according to WBC count; and 256, according to PMN cell differentiation The cut-off of 2478.89 cells/µl in the WBC count (sensitivity: 87.70%; specificity: 88.10%) and the cut-off of 66.99% in PMN differentiation showed the best accuracy (sensitivity: 86.00%; specificity: 88.80%). Other published cut-offs for WBC were tested in this cohort and showed the following accuracy: 3000/µl (EBJIS/ICM; sensitivity: 82.10%; specificity: 91.00%), 2000/µl (sensitivity: 89.60%; specificity: 83.40%), and 1500/µl (sensitivity: 91.50%; specificity: 75.00%). The published cut-offs for PMN had the following accuracy in this cohort: 80% (ICM; sensitivity: 66.3%; specificity: 96.50%), 70% (sensitivity: 82.6%; specificity: 90%), and 65% (EBJIS, sensitivity: 86%; specificity: 88.8%). This study aims to improve current cut-offs for PMN- and WB-Count, even though PJI diagnosis is based on the combination of all defined tests. The optimal diagnostic cut-off of WBC and PMN counts was found to be 2479/µL and 67%, respectively, whereas ICM cut-offs in this cohort seem too high, as they provide high specificity but very low sensitivity. On the other hand, a cut-off for WBC count of 1500/µl alone would be very low, leading to low specificity and very high suspicion of PJI. The current consensus guidelines could be actualized considering these results to significantly improve the diagnostic quality. II.

Prevalence, Etiology, Antimicrobial Susceptibility Testing and Predictors of Urinary Tract Infection among Neonates with Clinical Sepsis

Background and Aim: The most common pediatric infection is urinary tract infection (UTI). Neonates who suffer from neonatal sepsis remain among the most vulnerable to death and morbidity, especially in developing countries. The present study aimed to determine the prevalence, etiology, and susceptible antimicrobial agents of UTIs among neonates with clinical sepsis. Patients and Methods: This cross-sectional study was carried out on 128 sepsis diagnosed neonates admitted to the Department of Pediatrics, Microbiology and Infectious Diseases, Niazi Welfare Teaching Hospital, Sargodha from September 2021 to May 2022. All neonates aged ≤ 28 days diagnosed of clinical sepsis and consent provided by their parents/guardian were enrolled. An interviewed based questionnaire was used for data collection from neonate’s parents or caregiver. The questionnaire included information on the socio-demographics and clinical presentations of neonates, as well as maternal history and laboratory examinations. The history is taken from prenatal to postnatal, including birth weight analysis and birth conditions. Neonates underwent general and local examinations to determine their state of consciousness, vital signs, and weight. We examined the abdomen (for tenderness and abdominal distention) and the nervous system (to elicit suckling and motor reflexes). A hematological analyzer was used to test the full blood picture (FBP). SPSS version 27 was used for data analysis. Results: Of the total 128 neonates, there were 76 (59.4%) females and 52 (40.6%) male neonates. The overall mean age was 6.4 ± 0.36 days with majority of neonates 112 (87.5%) were < 7 days. The low birth weight and low Apgar score were found in 13 (10.2%) and 16 (12.5%) neonates respectively. Of all neonates, the failure to breastfeed was found in 26 (20.3%) being the most common clinical symptom followed by an increase in breathing rate 21 (16.4%), diarrhea 19 (14.8%), gritting 16 (12.5%), altered mental status 12 (9.4%), and jaundice 11 (8.6%). The incidence of UTI was 20.3% (n=26). The prevalence of separated bacterial agents such as Klebsiella pneumonia and Enterobacter spp. was 61.5% (n=16) and 38.5% (n=10) respectively. Ciprofoxacin and amikacin were both effective against 90% and 60% of the bacterial isolates, respectively. The UTI potential predictors involved prolong labour, positive leucocyte esterase test, Low Apgar score, and positive urine nitrite test. Conclusion: The present study found that the prevalence of UTI was 20.3%. Failure to breastfeed was the most common clinical symptom followed by an increase in breathing rate, diarrhea, gritting, altered mental status, jaundice, convulsion, and cyanosis. Klebsiella pneumonia and Enterobacter spp. were the most prevalent separated bacterial agents. Ciprofoxacin and amikacin were both effective in bacterial isolates. Keywords: UTI, Clinical sepsis, Neonates, Antibiotic sensitivity

Diagnosis of leucospermia in the stallion

The lack of standardized tests and interpretative criteria makes the diagnosis of stallion leucospermia difficult. Our objectives were to evaluate the ability of six diagnostic tests to detect polymorphonuclear cells (PMNs) in stallion semen, and to determine the concentration of PMNs that affects sperm motility. We hypothesized that all tests have diagnostic value, and that low concentrations of PMNs affect sperm motility. One ejaculate was obtained from six stallions. Aliquots of 50 ×106 purified sperm from each stallion were incubated with six concentrations of purified PMNs: 1) no PMNs, 2) 0.25 ×106 PMN/ml, 3) 0.5 ×106 PMN/ml, 4) 2.5 ×106 PMN/ml, 5) 5 ×106 PMN/ml, and 6) 10 ×106 PMN/ml. Each treatment was performed in triplicate. The PMNs were quantified using a hemacytometer (phase contrast microscopy), cytology (light microscopy), a commercial leucocyte esterase test (dipstick), a commercial peroxidase test (light microscopy), and immunolabeling of the neutrophil marker CD13 (flow cytometry). Sperm motility was evaluated after 4 h at 38 °C. The frequency of results obtained with the esterase test differed among treatments (P<0.0001). Negative or trace results were observed only with ≤ 0.5 ×106 PMNs/ml. A small number was observed in intermediate samples. In samples with ≥ 5 ×106 PMN/ml, only moderate or large results were obtained. Among quantitative tests, the hemacytometer count and flow cytometry detected differences with the control treatment at the lowest PMN concentration (2.5 ×106 PMN/ml; P<0.001). Total and progressive sperm motility were lower in samples with ≥5 ×106 PMN/ml than in those with lower concentrations (P<0.0001). Thus, a sample was considered leucospermic with ≥ 5 ×106 PMN/ml. The leucocyte esterase dipstick test had the best sensitivity (100%), followed by cytology (78%), peroxidase test (60%), flow cytometry (56%) and hemacytometer count (47%). The esterase test had the lowest specificity (65%), whereas the specificity of all other tests was 95%. In conclusion, presence of ≥5 ×106 PMNs/ml was associated with impaired sperm motility. The leucocyte esterase dipstick test is a simple, economic and sensitive stall-side test to screen semen for presence of PMNs in quantities capable of affecting sperm motility. Because of the lower specificity, we recommend confirming positive esterase results with the identification of peroxidase-positive cells under light microscopy, or CD13-positive cells using flow cytometry.

Evaluation of Bacteriuria in Urine Samples Using Nitrite Test and Leucocyte Esterase Test Versus Urine Culture Among Undergraduate Students in Owerri, Nigeria

Evaluation of Bacteriuria in Urine Samples Using Nitrite Test and Leucocyte Esterase Test Versus Urine Culture Among Undergraduate Students in Owerri, Nigeria

What is the Accuracy of a Rapid Strip Test That Detects D-lactic Acid in Synovial Fluid for the Diagnosis of Periprosthetic Joint Infections?

D-lactic acid is a specific marker produced almost exclusively by bacterial species; thus, the appearance of this marker in synovial fluid may indicate periprosthetic joint infection (PJI). Recently, studies have investigated the accuracy of enzyme-linked laboratory tests that detect D-lactic acid in synovial fluid to diagnose PJI. However, to our knowledge, no studies have determined the usefulness of rapid strip tests that detect D-lactic acid in synovial fluid in the diagnosis of PJI. (1) What is the best cutoff value for the rapid D-lactic acid strip test for diagnosing PJI? (2) What are the diagnostic accuracies (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) of the rapid D-lactic acid strip test and two different rapid leukocyte esterase (LE) strip tests? This prospective study enrolled 157 patients who underwent revision THA or TKA from May 2021 to February 2022 at a single orthopaedic center. Seventy percent (110 of 157) were eligible for analysis; 10% of these patients (15 of 157) were excluded based on the exclusion criteria (causes of revisions and additional comorbidities that may interfere with the results), and 20% (32 of 157) of the synovial fluid samples could not be tested (dry taps and blood-contaminated samples that could not be centrifuged). We performed the following off-label diagnostic tests on synovial fluid samples collected from all patients: the D-lactic acid strip test (QuantiQuick TM , BioAssay System), two different LE strip tests (10 EA from ARKRAY and BM 10 from BioMaxima). Differently colored strips were marked with symbols (from [-] to [++++] for D-lactic acid and from [-] to [+++] for LE tests) according to the manufacturers' instructions. For the LE tests, results were different for (++), which corresponds to a minimal value of 250 leu/mL for 10 EA and 125 leu/mL for BM 10 tests. The diagnostic standard for the presence or absence of PJI in this study was the International Consensus Meeting (ICM) 2018 criteria; based on these criteria (without the application of an LE test as a minor criterion), all patients were assessed and divided into two groups. Patients who did not meet the criteria for PJI and underwent revision for aseptic loosening, implant malposition, instability, or implant damage were included in the aseptic revision total joint arthroplasty group (68 patients). Patients with a fistula penetrating the joint, those with two positive culture results of the same pathogen, or those with ≥ 6 points according to ICM 2018 minor criteria were enrolled in the PJI group (42 patients). To ascertain the best cutoff value for the rapid D-lactic acid and both LE strip tests for diagnosing PJI, we used collected results, generated a receiver operating characteristic curve, and calculated the Youden index. To determine the accuracies of the diagnostic tests, we calculated their sensitivities, specificities, PPVs, and NPVs against the diagnostic standard (the ICM 2018 criteria). The best cutoff value for D-lactic acid was 22.5 mg/L, which corresponded to a reading of (+) on the test strip. For D-lactic acid, in the diagnosis of PJI, the sensitivity was 83% (95% confidence interval [CI] 68% to 92%) and specificity was 100% (95% CI 93% to 100%). For both LE strip tests, the best cutoff value was the same as that proposed in the ICM 2018 criteria. For LE (10 EA), the sensitivity was 81% (95% CI 66% to 91%) and specificity was 99% (95% CI 91% to 100%); for LE (BM 10), sensitivity was 81% (95% CI 65% to 91%) and specificity was 97% (95% CI 89% to 100%). A rapid off-label D-lactic acid strip test is valuable for diagnosing PJI. The results of this study indicate very good accuracy with comparable sensitivity and specificity for both LE strip tests. The usefulness of the test in a group of patients with chronic inflammatory diseases and the reproducibility of the reading by different researchers were not analyzed in this study and require further investigations. Before a rapid D-lactic strip test is routinely used for diagnosing PJI, multicenter studies on a larger group of patients should be conducted.Level of Evidence Level II, diagnostic study.

The Accuracy of Rapid Urine Tests in Detecting Asymptomatic Bacteriuria in Pregnancy at University of Maiduguri Teaching Hospital, Maiduguri, Nigeria

Background: Asymptomatic bacteriuria (ASB) is the most prevalent Urinary tract infection (UTI). The gold standard for detecting ASB is urine culture, which requires trained personnel who are not always readily available in some parts of the world. Quick office-based tests such as urine microscopy and reagent strip testing are also used as screening tests at points of care, reserving culture for positive and symptomatic cases. Objectives: This study determined the risk factors for ASB and the accuracy of reagent strip testing and microscopy in detecting ASB among pregnant women. Methods: A cross-sectional study of 150 women attending the antenatal clinic of the University of Maiduguri Teaching Hospital (UMTH) in Maiduguri, Nigeria, was conducted from 3rd October to 13th December 2010. Demographic and clinical variables were obtained. Midstream urine specimens were collected from each patient and used for reagent strip testing, microscopy, culture and antibiotic susceptibility testing. The performance of the various tests alone and in combination was evaluated using urine culture as the standard. Results: Sickle cell trait, history of UTI before index pregnancy and anaemia at booking were significant risk factors for the development of ASB. A combination of positive leucocyte esterase and nitrite tests had specificity and a positive predictive value of 100% each. Similarly, the combination of pus cell count and gram stain, termed enhanced urinalysis had specificity and positive predictive values of 99.1% and 95.0%, respectively. Conclusion: Sickle cell trait, UTI before index pregnancy and anaemia at booking are significant risk factors for ASB. A combination of negative dipstick leucocyte esterase, nitrite, and negative enhanced urinalysis effectively rules out ASB. Urine culture can be restricted to positive and symptomatic patients.

Diagnostic Accuracy for Periprosthetic Joint Infection Does Not Improve by a Combined Use of Glucose and Leukocyte Esterase Strip Reading as Diagnostic Parameters.

The diagnosis of periprosthetic infections (PJI) can be challenging in clinical practice because the clinical presentations of aseptic loosening and low-grade infections are similar. Semiquantitative evaluation of leukocyte esterase (LE) in synovial fluid using a urine strip test has already established itself as a diagnostic method over the past decade. The analysis of LE in synovial fluid leads to a high number of false-positive test results. In the present study, the value of a combined semiquantitative determination of glucose and LE in synovial fluid to improve the diagnosis of PJI was investigated. Over a 4-year period, 145 synovial samples were collected from patients who developed joint effusion after arthroplasty. LE and glucose test strips were considered as an index test for the diagnosis of PJI. A ++ or +++ LE and a negative glucose test strip reading were considered as positive test results. Modified diagnostic criteria for PJI as recommended by the Musculoskeletal Infection Society (MSIS) served as the reference test, except that intraoperative findings were excluded. Forty-six out of 145 samples were classified as septic complication according to the reference test. In regard to PJI, our data showed that combined use of LE and glucose strip test reading displayed a 98.0% specificity (95% confidence interval (CI): 95.2% to 100%), a 50% sensitivity (95% CI: 35.6% to 64.4%), a 92% positive predictive value (95% CI: 81.4% to 100.0%), and an 80.3% negative predictive value (95% CI: 73.2% to 87.4%). In contrast, the exclusive analysis of LE on the urine strip to diagnose PJI demonstrated a 90.9% specificity (95% CI: 85.2% to 96.6%), a 67.4% sensitivity (95% CI: 53.8% to 80.9%), a 77.5% positive predictive value (95% CI: 64.6% to 90.4%), and an 85.7% negative predictive value (5% CI: 79.0% to 92.4%). A combination of LE and glucose test pad reading is considered superior as a potential “rule-in” method for the diagnosis of PJI compared with LE test pad analysis alone. However, combined LE and glucose synovial fluid testing also demonstrated lower test sensitivity and thus diagnostic accuracy compared with LE analysis alone. Therefore, combined glucose and LE test pad analysis does not represent a sufficient diagnostic standard to exclude PJI with certainty.