OBJECTIVETo investigate the biuret reagent to detect proteins in the application, the impact of different test conditions for test results.

METHODSThe biuret method to select three different instruments, reagents, calibrators are arranged in combination to form 27 sets of detection systems, each detection system is a combination of 5 serum samples for testing, 5 measured values obtained, the selection process normality good a serum for the study to determine the mean value of all AST after culling outliers obtained in order to calculate the various detection systems use a combination of biuret reagent to detect proteins bias.

RESULTSThe use of different detection equipment to detect proteins biuret reagent bias, homogeneity of variance (P = 0.467), the difference was not statistically significant (F = 1.688, P = 0.421). different detection reagents using biuret reagent to detect proteins bias, homogeneity of variance (P = 0.574), a statistically significant difference (F = 5.784, P = 0.011). different calibrators use biuret reagent to detect proteins bias, homogeneity of variance (P = 0.467), the difference was statistically significant (F = 5.289, P = 0.000).

CONCLUSIONBiuret reagent in the detection of protein applications, impact detection reagents and calibrators will test result, during the test than when it is necessary to detect deviation detection reagents and calibrators due to be considered.

From the perspective of technical review, this paper made statistics on the supplement contents of
Chemistry, Clinical/standards* ; China ; Indicators and Reagents ; Reagent Kits, Diagnostic/standards*

BACKGROUND: Although the same equipment and reagents can be employed for inspecting identical samples, the setting and verification methods for the corresponding reference intervals differ from each other, and such methods are not well established. To address the issues associated with establishing and validating reference intervals, a Web-based application is proposed for collaboratively setting reference intervals. METHODS: A Web application was designed for automatically providing the statistical results associated with a reference interval upon receiving the corresponding test results from participating institutions and incorporating the cumulative data. RESULTS: By employing the proposed Web-based application (www.referencerange.org), reference intervals can be collaboratively set based on objective and statistical analyses incorporating clinical chemistry results obtained from Korea Healthcare Association in the years 2016 and 2017. Cumulative data obtained from the existing input peer group associated with an inspection are updated in real time, and the current set reference interval is displayed in real time. CONCLUSIONS: In this study, a Web-based application is designed for collaboratively setting reference intervals whereby all Korean laboratories can easily participate, collectively set reference intervals, and apply the set reference intervals. Hence, the proposed application can aid in providing basic data associated with health information.
Chemistry, Clinical ; Delivery of Health Care ; Indicators and Reagents ; Korea ; Peer Group

BACKGROUND: JEOL BioMajesty JCA-BM6010/C (JCA-BM6010/C, JEOL Ltd., Japan) is a recently developed ultra-compact automated clinical chemistry analyzer with a throughput of 1,200 tests per hour. Here, we present the first performance evaluation of JCA-BM6010/C. METHODS: We evaluated the precision, linearity, correlation, accuracy, and carryover of 11 analytes (ALP, ALT, AST, calcium, creatinine, GGT, glucose, LDH, total bilirubin, total protein, and uric acid) using the JEOL closed reagent (JEOL Ltd.) according to the guidelines of the Clinical Laboratory Standards Institute. Linearity was further evaluated for ALT, AST, and GGT using open reagents by Sekisui (Japan). The performance of JCA-BM6010/C was compared to that of the Roche-Hitachi Cobas 8000 c702 chemistry autoanalyzer (Cobas 8000, Roche Diagnostics, Switzerland). Its performance using open reagents from Denka Seiken (Japan), Roche, and Sekisui was also evaluated. RESULTS: The total coefficients of variation (CV) for all analytes were 1.0–2.7%. Linearity was observed for all analytes over the entire tested analytical range (R²≥0.99). The results of JCA-BM6010/C strongly correlated (r≥0.988) with those of Cobas 8000 for all evaluated analytes except LDH (r=0.963), as well as for all open reagents. Recovery rates for creatinine, glucose, calcium, and uric acid were 96.6–101.5% and 98.7–109.3% with the JEOL exclusive and open reagents, respectively. Sample carryover was less than 0.34%. CONCLUSIONS: JCA-BM6010/C showed acceptable performance in the precision, linearity, correlation, accuracy, and sample carryover analyses and in the method comparison. Therefore, it could be a useful routine laboratory medical analyzer.
Bilirubin ; Calcium ; Chemistry ; Chemistry, Clinical* ; Creatinine ; Glucose ; Indicators and Reagents ; Methods ; Uric Acid

BACKGROUND: Self-reports of smoking may not always be reliable. A number of biochemical markers have been used to validate claims of nonsmoking, among which the most widely used specific marker has been the nicotine metabolite cotinine. This study was conducted to evaluate the performance of the enzyme immunoassay (EIA) for urinary cotinine to determine smoking status. METHODS: Questionnaires on smoking and urinary cotinine measures were studied in 287 persons. Urinary cotinine concentration was measured by the Cotinine Enzyme Immunoassay (Diagnostic Reagents, Inc., CA, USA) on the 502X Multiple Chemistry Unit (A &T Co., Tokyo, Japan). RESULTS: Using cutoffs of 0 ng/mL, 20 ng/mL or 100 ng/mL for urinary cotinine measured by the EIA method, the sensitivities were 100%, 97.6%, and 94.4% respectively and the specificities were 97.5%, 98.8%, and 100% respectively. By retrograde telephone questionnaires, 3.8% of the subjects were confirmed as deceiving their smoking status. Active smokers of <10 cigarettes per day had a lower mean cotinine level (492 ng/mL) than those who smoked > or =10 cigarettes (1, 052 ng/mL). CONCLUSIONS: Urinary cotinine measured by EIA is a rapid, lab-based test that can reliably determine smoking status. Considering the various purpose of the test, different cut-offs should be used.
Biomarkers ; Chemistry ; Cotinine* ; Humans ; Immunoenzyme Techniques ; Indicators and Reagents ; Nicotine ; Smoke ; Smoking ; Telephone ; Tobacco Products ; Surveys and Questionnaires

BACKGROUND: To understand causes of abnormal reaction for the urinalysis, we analyze the interfering substances of clinical urine samples. We focused the effect of urinary vitamin C and fluorescein sodium to the urine chemistry especially glucose, hemoglobin, and leukocyte esterase. METHODS: Incidence of urinary vitamin C was determined for patients and people underwent a medical check–up. We decided dipstick results of glucose, hemoglobin, and leukocyte esterase as false negative based on urine sediment and serum glucose results. Dipstick urinalysis was tested by URiSCAN Pro III with URiSCAN 11 strip (YD Diagnostics, Korea). Urine sediments tests were performed by manual microscopic analysis or Sysmex UF–1000i (Sysmex Co., Japan). RESULTS: The incidence of vitamin C was 20.4% for all subjects. The positive rate of the medical check-up group (34.6%) was higher than others. When vitamin C was detected in clinical urine samples, 42.3%, 10.6%, and 8.2% were defined as false negative for glucose, hemoglobin, and leukocyte esterase dipstick tests, respectively. Fluorescein sodium also interfered on the results of hemoglobin and leukocyte esterase of the dipstick reagents. CONCLUSIONS: Vitamin C was frequently found in the clinical urine samples, and its incidence was higher in the people who underwent medical check-up. The urinary vitamin C and fluorescein sodium can cause interferences in urine dipstick results. Thus, it is expected that present study will give useful information to predict false negative rates of urine dipstick tests by vitamin C and fluorescein sodium.
Ascorbic Acid ; Blood Glucose ; Chemistry ; Fluorescein ; Glucose ; Humans ; Incidence ; Indicators and Reagents ; Leukocytes ; Urinalysis*

BACKGROUND: Many reagents have been developed along with advances in chemistry auto analyzer. Deciding on an appropriate reagent is required for an accurate test, diagnosis and efficient laboratory management. We evaluated Cica Liquid reagent produced by Kanto chemical corporation (Tokyo, Japan) for checking reagent ability. METHODS: Twelve chemistry reagents (AST, ALT, ALP, glucose, BUN, creatinine, total bilirubin, direct bilirubin, cholesterol, triglyceride, iron, magnesium) were tested on precision, linearity, interference, and correlation. We have evaluated using Hitachi 7600 (Hitachi High Technologies co., Japan) chemistry auto analyzer in accordance with the CLSI guidelines EP5-A, EP6-A, EP7-A, EP9-A2. EP_Suite (Marchem Associates Inc., USA) and SPSS ver. 11.0 (SPSS Inc., USA) were used for statistics. RESULTS: Precision results were satisfactory to CLIA '88 in all of the analytes except for ALP and magnesium. The linearity was satisfactory in measurement ranges as all analytes showed linearity in polynomial regression result or relative nonlinearity of less than 2.5%. Coefficients of correlation were above 0.985 in all analytes except for direct bilirubin and magnesium. When interference test results were compared with criteria of CLIA '88, low level of AST was positively interfered by hemoglobin and magnesium was negatively interfered by bilirubin. CONCLUSIONS: In conclusion, the Kanto Cica Liquid reagents are valuable in clinical laboratory, since they showed good precision, linearity, and correlation with other reagents.
Bilirubin ; Chemistry* ; Cholesterol ; Creatinine ; Diagnosis ; Glucose ; Indicators and Reagents* ; Iron ; Magnesium ; Triglycerides

The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide.
Chromatography, High Pressure Liquid ; Diterpenes ; analysis ; isolation & purification ; Electrolysis ; Electrolytes ; chemistry ; Indicators and Reagents ; chemistry ; Linear Models ; Reproducibility of Results

Routine protein assays are usually affected with various compounds, and we need to use different protein quantification protocol to deal with different interference. In order to simplify the procedure, we developed a new method, in which the components and concentrations of the reagents were modified mainly based on classic Folin-Ciocalteu's reagent for reducing the susceptibility to interfering substances. Standard curves of the new method were established with different levels of bovine serum albumin, and then, we assessed and evaluated the detectable wavelengths and stability. In particular, the tolerability to several interfering substances was analyzed by using cytolysis solutions containing different chemicals. Our data in this study show that the new method could be applied to detecting protein concentrations accurately, even in the presence of surfactants such as 10% sodium dodecyl sulfate (SDS), 2% NP-40, or 1% TrintonX-100, chelators of 25 mmol/L EDTA or 1 mmol/L Ethylene glycol bis (2-aminoethyl) tetraacetic acid (EGTA), reductants of 1 mmol/L Dithiothretol (DTT) orbeta-Mercaptoethanol (ME), or nitrogen-containing compounds of 0.5 mol/L ammonium sulphate or 4 mol/L urea. Taken together, these results indicate that the new approach significantly improves the tolerance to the interfering substances, which could be potentially useful in measuring the contents of proteins interfered with such substances.
Animals ; Edetic Acid ; chemistry ; Egtazic Acid ; chemistry ; Indicators and Reagents ; chemistry ; Molybdenum ; chemistry ; Proteins ; analysis ; Serum Albumin, Bovine ; analysis ; Surface-Active Agents ; chemistry ; Tungsten Compounds ; chemistry

BACKGROUND: To prevent complications of diabetes mellitus, diabetic patients should test blood glucose level frequently. In these days, glucometers are widely used for self-monitoring and many kinds of products are introduced. We performed the present study to evaluate the performance of glucophone (GlucoPack(TM), Infopia Co. Ltd., Anyang, Korea) as a point-of-care testing glucometer. METHODS: Glucometers including glucophone and Finetest(TM) (Infopia Co. Ltd., Anyang, Korea) were evaluated for precision, linearity, and accuracy. The interpersonal variation by different operators, reagent stability, comparison capillary blood with venous blood, and user acceptability were also evaluated. RESULTS: Glucophone and Finetest glucometer showed excellent precisions wtih less than 5% of CVs of within-run and total precision. Linearity was also satisfactory from 24 to 517 mg/dL for glucophone and Finetest glucometer. Comparison with routine chemistry autoanalyzer, TBA-200FR showed close concordance over the entire range of evaluated concentrations (y = 0.8397x + 3.8351, x = TBA-200FR, y=glucophone, R2=0.9523). There were no significant changes in test results during exposure period at room temperature after opening the reagents. Generally random users expressed high satisfaction to glucophone with the exception of complicated operating method. CONCLUSION: Glucophone showed excellent precision, linearity, and correlation with the reference method. Because POCT glucometers are influenced by operator and multiple external factors, it is important that users recognize interfering factors and preservation conditions of test strips. It is hoped that glucophone is a good POCT glucose meter by establishment continuous quality control system and improvement of operation.
Blood Glucose ; Capillaries ; Chemistry ; Diabetes Complications ; Diabetes Mellitus ; Glucose ; Gyeonggi-do ; Hope ; Humans ; Indicators and Reagents ; Quality Control