BilR is a gut microbial enzyme that reduces bilirubin to urobilinogen.

Metabolism of haem by-products such as bilirubin by humans and their gut microbiota is essential to human health, as excess serum bilirubin can cause jaundice and even neurological damage. The bacterial enzymes that reduce bilirubin to urobilinogen, a key step in this pathway, have remained unidentified. Here we used biochemical analyses and comparative genomics to identify BilR as a gut-microbiota-derived bilirubin reductase that reduces bilirubin to urobilinogen. We delineated the BilR sequences from similar reductases through the identification of key residues critical for bilirubin reduction and found that BilR is predominantly encoded by Firmicutes species. Analysis of human gut metagenomes revealed that BilR is nearly ubiquitous in healthy adults, but prevalence is decreased in neonates and individuals with inflammatory bowel disease. This discovery sheds light on the role of the gut microbiome in bilirubin metabolism and highlights the significance of the gut-liver axis in maintaining bilirubin homeostasis.

A high urinary urobilinogen/serum total bilirubin ratio indicates acute hepatic porphyria in patients with abdominal pain.

Acute hepatic porphyria (AHP) has always been a diagnostic dilemma for physicians due to its variable symptoms. Correct diagnosis mainly depends on the detection of an elevated urinary porphobilinogen (PBG), which is not a routine test and highly relies on the physician's awareness of AHP. In the present study, we identified a more convenient indicator during routine examinations to improve the diagnosis of AHP. We found that AHP patients showed a significant higher "FALSE" urinary urobilinogen level caused by urinary PBG during the urinalysis when detected by strips impregnated with Ehrlich reagent (P < 0.05). And a remarkable increase in the urinary urobilinogen/serum total bilirubin ratio was observed in AHP patients. The area under the ROC curve of this ratio for AHP was 1.000 (95% confidence interval 1.000-1.000, P < 0.01). A cutoff value of 3.22 for this ratio yielded a sensitivity of 100% and a specificity of 100% to distinguish AHP patients from the controls. Thus, we proved that a "falsely" high urinary urobilinogen level that was adjusted by the serum total bilirubin level (urinary urobilinogen/serum total bilirubin ratio) could be used as a sensitive and specific screening marker for AHP in patients with abdominal pain.

Pyrroles as a Potential Biomarker for Oxidative Stress Disorders.

Redox imbalance or oxidative stress that results from both environmental and genetic factors is observed in patients with schizophrenia. Therefore, identifying markers of oxidative stress in the early stages of psychosis and using antioxidant treatments as an adjuvant to antipsychotics has important implications. The reaction of p-N,N-dimethylaminobenzaldehyde (DMAB) with pyrrole moieties has been well studied for well over a century for use as a marker of oxidative stress dysregulation. Throughout this time, pyrroles have been investigated with varying veracity in urine extracts to identify elevated levels in patients diagnosed with schizophrenia. Since the 1960's, various claims have been made with respect to what causes the colour change when DMAB is added to urine extracts. Whilst the substances from this reaction have not been fully elucidated, an objective look at most studies indicates that urobilinogen is likely to be one them. Urobilinogen has also been identified as a major interferent in our results. Both pyrroles and urobilinogen condense the DMAB reaction system (form condensation products) and are quite different. The urobilinogen detected in urine forms when gut microflora chemically reduces the bilirubin content of bile acids. In comparison, evidence suggests that the pyrrole fraction originates from the fragmentation of regulatory haem by reactive oxygen species (ROS) such as hydrogen peroxide and super and nitrous oxides. Clinical studies in our laboratories have established that pyrroles as a urine biomarker have specificity in detecting schizophrenia; however, caution must be applied as the readings are subject to interference by other DMAB active compounds that are present, such as urobilinogen. This review highlights the initial chemistry in isolating pyrroles and provides recommendations for standardised laboratory testing to ensure pyrroles are correctly measured and distinguished from other by-products.

The Combined Escherichia coli Nissle 1917 and Tryptophan Treatment Modulates Immune and Metabolome Responses to Human Rotavirus Infection in a Human Infant Fecal Microbiota-Transplanted Malnourished Gnotobiotic Pig Model.

Human rotavirus (HRV) is a major cause of childhood diarrhea in developing countries where widespread malnutrition contributes to the decreased oral vaccine efficacy and increased prevalence of other enteric infections, which are major concerns for global health. Neonatal gnotobiotic (Gn) piglets closely resemble human infants in their anatomy, physiology, and outbred status, providing a unique model to investigate malnutrition, supplementations, and HRV infection. To understand the molecular signatures associated with immune enhancement and reduced diarrheal severity by Escherichia coli Nissle 1917 (EcN) and tryptophan (TRP), immunological responses and global nontargeted metabolomics and lipidomics approaches were investigated on the plasma and fecal contents of malnourished pigs transplanted with human infant fecal microbiota and infected with virulent (Vir) HRV. Overall, EcN + TRP combined (rather than individual supplement action) promoted greater and balanced immunoregulatory/immunostimulatory responses associated with greater protection against HRV infection and disease in malnourished humanized piglets. Moreover, EcN + TRP treatment upregulated the production of several metabolites with immunoregulatory/immunostimulatory properties: amino acids (N-acetylserotonin, methylacetoacetyl-CoA), lipids (gamma-butyrobetaine, eicosanoids, cholesterol-sulfate, sphinganine/phytosphingosine, leukotriene), organic compound (biliverdin), benzenoids (gentisic acid, aminobenzoic acid), and nucleotides (hypoxathine/inosine/xanthine, cytidine-5'-monophosphate). Additionally, the levels of several proinflammatory metabolites of organic compounds (adenosylhomocysteine, phenylacetylglycine, urobilinogen/coproporphyrinogen) and amino acid (phenylalanine) were reduced following EcN + TRP treatment. These results suggest that the EcN + TRP effects on reducing HRV diarrhea in neonatal Gn pigs were at least in part due to altered metabolites, those involved in lipid, amino acid, benzenoids, organic compounds, and nucleotide metabolism. Identification of these important mechanisms of EcN/TRP prevention of HRV diarrhea provides novel targets for therapeutics development. IMPORTANCE Human rotavirus (HRV) is the most common cause of viral gastroenteritis in children, especially in developing countries, where the efficacy of oral HRV vaccines is reduced. Escherichia coli Nissle 1917 (EcN) is used to treat enteric infections and ulcerative colitis while tryptophan (TRP) is a biomarker of malnutrition, and its supplementation can alleviate intestinal inflammation and normalize intestinal microbiota in malnourished hosts. Supplementation of EcN + TRP to malnourished humanized gnotobiotic piglets enhanced immune responses and resulted in greater protection against HRV infection and diarrhea. Moreover, EcN + TRP supplementation increased the levels of immunoregulatory/immunostimulatory metabolites while decreasing the production of proinflammatory metabolites in plasma and fecal samples. Profiling of immunoregulatory and proinflammatory biomarkers associated with HRV perturbations will aid in the identification of treatments against HRV and other enteric diseases in malnourished children.

Feasibility of Voltage-Applied SERS Measurement of Bile Juice as an Effective Analytical Scheme to Enhance Discrimination between Gall Bladder (GB) Polyp and GB Cancer.

A unique surface-enhanced Raman scattering (SERS) measurement scheme to discriminate gall bladder (GB) polyp and GB cancer by analysis of bile juice is proposed. Along with the high sensitivity of SERS, external voltage application during SERS measurement was incorporated to improve sample discriminability. For this purpose, Au nanodendrites were constructed on a screen-printed electrode (referred to as AuND@SPE), and Raman spectra of extracted aqueous phases from raw bile juice samples were acquired using the AuND@SPE at voltages from -300 to 300 mV. The sample spectra resembled that of bilirubin, possessing an open chain tetrapyrrole, showing that bilirubin derivatives in bile juice were mainly responsible for the observed peaks. Discrimination of GB polyp and GB cancer using just the normal SERS spectra was not achieved but became apparent when the spectra were acquired at a voltage of -100 mV. When voltage-applied SERS spectra of bilirubin and urobilinogen (one of bilirubin's derivatives) were examined, a sudden intensity elevation occurring at -100 mV was observed for urobilinogen but not bilirubin. Based on examination of corresponding cyclic voltammograms, the potential-driven strong adsorption of urobilinogen (no faradaic charge transfer) on AuND occurring at -100 mV induced a substantial increase in SERS intensity. It was presumed that the content of urobilinogen in the bile juice of a GB cancer patient would be higher than that of a GB polyp patient, and the contained urobilinogen was sensitively highlighted by applying -100 mV during SERS measurement, allowing clear discrimination of GB cancer against GB polyp.

Annual Report of the Korean Association of External Quality Assessment Service on Urinalysis and Fecal Occult Blood Testing (2018) / 임상검사와정도관리

In 2018, external quality assessment trials for urinalysis and fecal occult blood (FOB) were performed using 1,590 participants. Urine chemistry tests were performed thrice while urine sediment and FOB tests twice. Urine chemistry tests comprised of pH, protein, glucose, ketone body, bilirubin, blood, urobilinogen, nitrite, leukocyte, and specific gravity analyses. The results of urine chemistry and specific gravity tests showed accuracy rates >95%, except for the pH test. The accuracy rate of urine sediments was low, especially for atypical calcium oxalate crystal and red blood cell cast. In the FOB quality test, reagents showed accuracy rates >90%, except for SD and GC Genedia FOB reagents. In the FOB quantitative test, Alfresa NS-Plus C instrument showed falsely high values in the FOB negative specimens.

Annual Report on the External Quality Assessment Scheme for Urinalysis and Fecal Occult Blood Testing in Korea (2017)

In 2017, external quality assessment trials for urinalysis and fecal occult blood (FOB) were performed with 1,544 participants. Urine chemistry tests were performed three times and urine sediment and FOB tests were evaluated 2 times. Urine chemistry tests consisted of pH, protein, glucose, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte, and specific gravity analyses. The results of the urine chemistry and specific gravity tests showed accuracy rates >95%. The accuracy rate of urine sediments was low, especially for fat droplets and atypical uric acid crystals. In the FOB quality test, all reagents showed accuracy rates >82%, which suggested the persistent improvement of false-positive reactions. In the FOB quantitative test, discrepant results depending on the instrument used were observed. To compensate for the result differences caused by the amounts of stool samples, the results should be reported using another unit (µg/g of stool).

Hemolysis during and after 21 days of head-down-tilt bed rest.

Hemoconcentration is observed in bed rest studies, descent from altitude, and exposure to microgravity. Hemoconcentration triggers erythrocyte losses to subsequently normalize erythrocyte concentration. The mechanisms of erythrocyte loss may involve enhanced hemolysis, but has never been measured directly in bed rest studies. Steady-state hemolysis was evaluated by measuring two heme degradation products, endogenous carbon monoxide concentration [CO] and urobilinogen in feces, in 10 healthy men, before, during, and after two campaigns of 21 days of 6° head-down-tilt (HDT) bed rest. The subjects were hemoconcentrated at 10 and 21 days of bed rest: mean concentrations of hemoglobin (15.0 ± 0.2 g/L and 14.6 ± 0.1 g/L, respectively) and erythrocytes (5.18 ± 0.06E6/µL and 5.02 ± 0.06E6/µL, respectively) were increased compared to baseline (all Ps < 0.05). In contrast, mean hemoglobin mass (743 ± 19 g) and number of erythrocytes (2.56 ± 0.07E13) were decreased at 21 days of bed rest (both Ps < 0.05). Indicators of hemolysis mean [CO] (1660 ± 49 ppb and 1624 ± 48 ppb, respectively) and fecal urobilinogen concentration (180 ± 23 mg/day and 199 ± 22 mg/day, respectively) were unchanged at 10 and 21 days of bed rest compared to baseline (both Ps > 0.05). A significant decrease in [CO] (-505 ppb) was measured at day 28 after bed rest. HDT bed rest caused hemoconcentration in parallel with lower hemoglobin mass. Circulating indicators of hemolysis remained unchanged throughout bed rest supporting that enhanced hemolysis did not contribute significantly to erythrocyte loss during the hemoconcentration of bed rest. At day 28 after bed rest, decreased hemolysis accompanied the recovery of erythrocytes, a novel finding.

Paper-Plastic Hybrid Microfluidic Device for Smartphone-Based Colorimetric Analysis of Urine.

In this work, a disposable paper-plastic hybrid microfluidic lab-on-a-chip (LOC) has been developed and successfully applied for the colorimetric measurement of urine by the smartphone-based optical platform using a "UrineAnalysis" Android app. The developed device was cost-effectively implemented as a stand-alone hybrid LOC by incorporating the paper-based conventional reagent test strip inside the plastic-based LOC microchannel. The LOC device quantitatively investigated the small volume (40 µL) of urine analytes for the colorimetric reaction of glucose, protein, pH, and red blood cell (RBC) in integration with the finger-actuating micropump. On the basis of our experiments, the conventional urine strip showed large deviation as the reaction time goes by, because dipping the strip sensor in a bottle of urine could not control the reaction volume. By integrating the strip sensor in the LOC device for urine analysis, our device significantly improves the time-dependent inconstancy of the conventional dipstick-based urine strip, and the smartphone app used for image analysis enhances the visual assessment of the test strip, which is a major user concern for the colorimetric analysis in point-of-care (POC) applications. As a result, the user-friendly LOC, which is successfully implemented in a disposable format with the smartphone-based optical platform, may be applicable as an effective tool for rapid and qualitative POC urinalysis.

Annual Report on the External Quality Assessment Scheme for Urinalysis and Faecal Occult Blood Testing in Korea (2016)

In 2016, external quality assessment trials for urinalysis and faecal occult blood (FOB) were performed with 1,487 participants in Korea. Urine chemistry and FOB tests were performed three and two times, respectively, whereas urine sediment was evaluated once using photography. Urine chemistry tests consisted of pH, protein, glucose, ketone, bilirubin, blood, urobilinogen, and nitrite levels; leukocyte count; specific gravity. The results of the urine chemistry and specific gravity tests showed accuracy rates of >95%. The accuracy rate of urine sediments was low, especially that for transitional epithelial cells and atypical crystals. In the FOB quality test, all reagents showed accuracy rates of >90%, which suggested the improvement of false-positive reaction. In the FOB quantitative test, discrepant results depending on the instrument used was observed. To compensate for the result differences caused by the stool samples, the results should be reported using another unit (µg/g of stool).

Annual Report on the External Quality Assessment Scheme for Urinalysis and Faecal Occult Blood Testing in Korea (2015)

In Korea, external quality assessment trials for urinalysis and faecal occult blood (FOB) were performed for 1,250 participants. Urine chemistry and FOB tests were evaluated three times, whereas urine sediment by photography was evaluated twice. Urine chemistry tests consisted those for pH, protein, glucose, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte, and specific gravity. The results of the urine chemistry and specific gravity tests showed accuracy rates >95%. In the FOB quality test, all reagents showed false-positive results. These reagents showed positive results in stool specimens containing >11 ng/mL haemoglobin. In the FOB quantitative test, the results were significantly different, based on the instrument used for the measurements. The average accuracy rate of urine sediments was 90.8%, whereas those for renal epithelial cells and cholesterol crystals were 83%.

Annual Report on External Quality Assessment Scheme for Urinalysis and Faecal Occult Blood Testing in Korea (2014)

In 2014, external quality assessment trials for urinalysis and faecal occult blood (FOB) were performed of 1,270 participants. Urine chemistry and FOB tests were evaluated three times, while urine sediment examination by photography was evaluated one time. Urine chemistry tests consisted of pH, protein, glucose, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte, and specific gravity (SG). The urine chemistry test results showed accuracy rates >95%, while those of the SG test by using a refractometer had accuracy rates <95%. In the FOB quality test, the Bio Focus reagent (BIO FOCUS Co., Korea) disclosed low positive rates (87%). The result of the FOB quantity test showed different values according to the instruments used, and the Kyowa instrument (Kyowa Chemical Industry Co., Japan) revealed the lowest values. In a urinary sediment examination, it is necessary to increase the frequency of the quality assessment trials due to low accuracy rates.

Black urine due to urobilinogen in a patient with alcoholic pellagra.

OBJECTIVES: Systemic exposure to drugs, chemicals and foods can cause abnormally colored urine. Food exposures are typically benign, but urine discoloration due to chemicals or drugs may indicate a potentially dangerous condition. Discolored urine can also be caused by medical problems. This brief report reviews the laboratory findings leading to lactic acidosis and elevated urine urobilinogen in an alcoholic patient with pellagra. DESIGN AND METHODS: A 66-year-old male, found unconscious in his hotel room, was brought to the emergency department (ED). Upon arrival he had hypothermia, a diffuse rash and altered mental status. During ED evaluation, a urinary catheter was placed and demonstrated black urine. Medical history noted chronic alcoholism, malnutrition, and poor self-care. RESULTS: Evaluation in the hospital suggested that his rash and neurologic changes were a result of malnutrition and vitamin deficiency. A thorough biochemical workup demonstrated that elevated urobilinogen was likely causing the patient's black urine. Serum niacin concentration was undetectable. His dermatitis improved with multivitamins, thiamine, and niacin as well as topical steroids. His mental status returned to baseline and he was discharged to a skilled nursing facility following a brief hospital stay. CONCLUSIONS: The patient's abnormal laboratory results were explained by his alcoholism and poor nutrition. Furthermore, urine color returned to normal with decreased concentration of urobilinogen, after vitamin supplementation and supportive medical care.

Development of the smartphone-based colorimetry for multi-analyte sensing arrays.

Here we report development of a smartphone app (application) that digitizes the colours of a colorimetric sensor array. A conventional colorimetric sensor array consists of multiple paper-based sensors, and reports the detection results in terms of colour change. Evaluation of the colour changes is normally done by the naked eye, which may cause uncertainties due to personal subjectivity and the surrounding conditions. Solutions have been particularly sought in smartphones as they are capable of spectrometric functions. Our report specifically focuses on development of a practical app for immediate point-of-care (POC) multi-analyte sensing without additional devices. First, the individual positions of the sensors are automatically identified by the smartphone; second, the colours measured at each sensor are digitized based on a correction algorithm; and third, the corrected colours are converted to concentration values by pre-loaded calibration curves. All through these sequential processes, the sensor array taken in a smartphone snapshot undergoes laboratory-level spectrometry. The advantages of inexpensive and convenient paper-based colorimetry and the ubiquitous smartphone are tied to achieve a ready-to-go POC diagnosis.

Non-clinical safety assessment of Hwangryunhaedok-tang: 13-week toxicity in Crl:CD Sprague Dawley rats.

Hwangryunhaedok-tang (Huang-Lian-Jie-Du-Tang in Chinese, Oren-gedoku-to in Japanese) is a traditional herbal medicine with a long history of use for anti-inflammatory purposes. In this study, subchronic toxicity of daily oral administration of a Hwangryunhaedok-tang water extract (HHT) at 0, 250, 750, and 2000mg/kg for 13weeks was examined in rats. Mortality, clinical signs, and changes in body weight, food consumption, clinical signs, ophthalmological examination, urinalysis, hematology, serum biochemistry, gross observation, organ weight, and histopathology were monitored in accordance with Good Laboratory Practice and OECD guidelines. We found no mortality or abnormality in clinical signs, body weight, serum biochemistry, or organ weight in HHT-treated groups in either sex. However, there were significant changes in glucose, bilirubin, urobilinogen, protein (only male) in urine after 2000mg/kg/day HHT treatment for both sexes. In hematological examinations, we found a significant decreased number of red blood cells (RBC), whereas, an increased the mean corpuscular volume, number of platelets, and rate of reticulocyte (RET) after 2000mg/kg/day HHT treatment of male rats. In male and female rats, 750 and 2000mg/kg/day HHT treatment decreased the number of RBC and increased RET. Histopathological examinations revealed stomach mucosal erosion in female rats (2000mg/kg/day). No-observed-adverse-effect levels were established for 750mg/kg HHT in rats under the conditions of this study. However, other toxicological studies are necessary to evaluate the safety of HHT fully.

Evaluation of an Automated Dipstick Device for Urinalysis-UriDoctor / 임상검사와정도관리

BACKGROUND: We evaluated the recently marketed UriDoctor analyser (DFI Co., Ltd., Korea) for urinalysis and measurement of microalbumin and creatinine in urine. METHODS: The precision within and betweenruns was evaluated using commercial control materials. The comparison evaluations were performed using patient urine samples. Urine dipstick tests for blood, bilirubin, urobilinogen, ketones, protein, nitrite, glucose, pH, specific gravity, and leukocyte esterase were performed with UriDoctor using CYBOW10 strips (DFI Co., Ltd., Korea) and with AX4030 using Aution Sticks 10EA (Arkray Inc., Japan), and the results were compared. Additionally, tests for microalbumin and creatinine were performed with UriDoctor using CYBOW2AC strips and with the Cobas c501 system (Roche Diagnostics, Germany), and the results were compared. RESULTS: The within-run and between-run precisions for urinalysis using UriDoctor were both 100%. The concordance rates and concordance rates including +/-1 grade between UriDoctor and AX4030 were as follows: blood (90%, 100%); bilirubin (97%, 100%); urobilinogen (98%, 100%); ketones (92%, 100%); protein (83%, 100%); nitrite (100%, 100%); glucose (85.0%, 100%); pH (58%, 94%); specific gravity (32%, 80%); leukocyte esterase (89%, 93%). The concordance rates between UriDoctor and the Cobas c501 system were as follows: microalbumin (71%); creatinine (46%); albumin-creatinine ratio (65%). CONCLUSIONS: UriDoctor showed good precision. There was significant agreement between the results of UriDoctor and AX4030, except for pH and specific gravity. The albumin-creatinine ratio showed relatively low specificity and high sensitivity; therefore, it would be more suitable for screening patients. The performance of UriDoctor when used with CYBOW10 and CYBOW2AC strips was satisfactory for clinical application.

Epstein-Barr virus-associated cholestatic hepatitis.

Epstein-Barr virus infection is common in children, usually presenting as infectious mononucleosis, including fever, tonsillitis and lymphadenopathy associated with self-resolving increase in transaminases. Cholestasis is rare in children with only a few cases reported but it was described in up to 55% of the adult population affected. We present a case of a 6-year-old boy with fever, vomiting and choluria. The physical examination showed hepatomegaly and jaundice and was otherwise unremarkable. The laboratory studies revealed increased transaminases (aspartate aminotransferase 97 U/L, alanine aminotransferase 166 U/L), hyperbilirubinaemia (total bilirubin 3.2 mg/dL, direct bilirubin 2.89 mg/dL) and increased γ-glutamyl transpeptidase (114 mg/dL). Urine urobilinogen was increased. The abdominal ultrasound showed hepatomegaly. Epstein-Barr viral capsid antibody IgM was positive and IgG was negative. Serological studies for other viruses were negative. We underline the need to consider Epstein-Barr virus in the cholestatic hepatitis differential diagnosis, in order to avoid unnecessary investigations.

Reliable laboratory urinalysis results using a new standardised urine collection device.

OBJECTIVES: While urine sampling is necessary in the diagnosis of urinary tract infection and electrolyte disturbances, the collection of urine in neonates and non-toilet-trained children is often difficult. A universal urine collection method providing representative urinalyses results is needed. The objective of this study is to evaluate the applicability of the currently used urine collection pads (gauze compresses) and a new urine collection device (Peespot). DESIGN AND METHODS: We tested the reliability of routine (semi-)quantitative urinalysis results with these two different kinds of urine collection methods in a laboratory model. Although important in clinical diagnosis, we did not evaluate the effects on cellular and other components such as casts in the urinary sediment. RESULTS: Most semi-quantitative variables determined by urine stick (pH, blood, protein, leukocytes, nitrite, glucose, ketones, bilirubin and urobilinogen) gave concordant results for both methods compared with native urine. Using the Peespot urine collection device, reliable quantitative results were obtained for calcium, chloride, glucose, magnesium, phosphate, potassium, sodium, osmolality, urea nitrogen and urate compared with native urine. Data were concordant only for chloride, phosphate, glucose, sodium and urea nitrogen by use of gauze compresses. CONCLUSIONS: Urine collection pads are non-invasive methods useful in the collection of urine in non-toilet-trained children. Because of better practical standardisation and more reliable (semi-) quantitative urinalysis results, the Peespot urine collection device is preferred for the collection of urine.

Urinalysis: The Usefulness and Limitations of Urine Dipstick Testing

The urinalysis is an essential part of the diagnostic work-up for kidney disease and other renal system disorders. The dipstick test allows rapid and simultaneous chemical analyses of urine, including factors such as pH, specific gravity, protein, glucose, ketones, occult blood, bilirubin, urobilinogen, nitrite, and leukocyteesterase. The chemical reactions on dipstick are complicated and can be affected by oxidizing, reducing, and discoloring substances in the urine. Therefore, false positive and false negative results are common in dipstick testing. To obtain reliable results with the dipstick, it is necessary to collect urine cleanly and examine the urine carefully. It is mandatory to clearly understand the principles of dipstick testing to evaluate abnormal findings. If the urine dipstick results suggest hematuria, proteinuria, or urinary tract infection, microscopy of the urine should be performed to confirm the findings.