Point-of-care detection of glycated hemoglobin using a novel dry chemistry-based electrochemiluminescence device.

As a good biomarker to reflect the average level of blood glucose, glycated hemoglobin (HbA1c) is mainly used for long-term glycemic monitoring and risk assessment of complications in diabetic patients. Previous analysis methods for HbA1c usually require complex pretreatment processes and large-scale biochemical analyzers, which makes it difficult to realize the point-of-care testing (POCT) of HbA1c. In this work, we have proposed a three-electrode dry chemistry-based electrochemiluminescence (ECL) biosensor and its self-contained automatic ECL analyzer. In this enzymatic biosensor, fructosyl amino-caid oxidase (FAOD) reacts with the hydrolysis product of HbA1c, and the produced hydrogen peroxide further reacts with luminol under the appropriate driving voltage, generating photons to realize the quantitative detection of HbA1c. Under optimized conditions, the biosensors have a good linear response to different concentrations of fructosyl valine (FV) ranging from 0.05 to 2 mM, with a limit of detection of 2 µM. The within-batch variation is less than 15%, and the biosensors still have 78% of the initial response after the accelerated aging test of 36 h at 37 °C. Furthermore, the recoveries for different concentrations of samples in whole blood were within 92.3-99.7%. These results illustrate that the proposed method has the potential for use in POCT of HbA1c.

A dry chemistry-based electrochemiluminescence device for point-of-care testing of alanine transaminase.

Liver disease causes serious public health problems because of its high prevalence, particularly affecting low- and middle-income countries. Alanine transaminase (ALT) is considered to be one of the most sensitive indicators for diagnosing liver disease. Although many strategies have been reported for ALT detection, few of them have solved the problem of automatic detection. In this work, for the first time, a dry chemistry-based electrochemiluminescence (DC-ECL) device is developed for point-of-care testing (POCT) of ALT, achieving real sample-to-answer detection. The proposed DC-ECL device consists of the following two components: (a) a DC-ECL chip consisting of the outer shell (including the top cap and pedestal) and detection layer (including the baseplate, electrode pad and carrier pad) and (b) an automatic ECL analyzer mainly including the data processing and instrument control unit, imaging detection unit, electrochemical reaction excitation unit, open detection window unit and rechargeable power supply. Under optimized conditions, the device had a wide detection range (0-1000 U/L), the ECL intensity linearly increased with ALT concentration (5-50 U/L) and logarithmic ALT concentration (50-1000 U/L), and the limit of detection was calculated to be 1.702 U/L. In addition, the DC-ECL device had the ability to measure ALT levels in human serum samples and showed acceptable selectivity, stability and repeatability. These results reveal that the DC-ECL device can overcome the disadvantages of traditional methods for ALT detection (such as high cost and requirement of professional technicians) and potentially opens the door to the development of similar POCT analyzers.

Effects of the hemolytic index on the test results of a dry chemistry analyzer and a verification of the hemolytic interference threshold.

BACKGROUND: This study verified and assessed 26 biochemical indicators tested by a dry chemistry analyzer using the hemolytic index test function to determine the degree of interference and the trends among the hemolysis samples on the test results. This study also sought to ensure that reasonable test reports could be issued taking into account practical clinical needs. METHODS: The samples were manually divided into the control group and the test group. The hemolytic index and biochemical indicators of the samples were tested using the Ortho Vitros 5600 to compare the deviation of the test results between the 2 groups. The judgment standard was set as 1/3 of the total error allowable as required by the quality assessment criterion of the National Center for Clinical Laboratories. The interference degree of hemolysis on the dry chemistry-based biochemical indicators was assessed, and the hemolytic thresholds of 26 biochemical indicators provided by the manufacturer were verified in terms of their validity and rationality. RESULTS: The hemolytic thresholds of 26 dry chemistry-based biochemical indicators were verified to analyze the degree of interference. The results revealed that hemolysis interfered with 17 indicators. Hemolysis positively interfered with the test results of phosphorus, creatine kinase, gamma glutamyl transpeptidase (γ-GGT), magnesium, iron, total protein, potassium, total bilirubin, lactate dehydrogenase, albumin, and aspartate aminotransferase, but negatively interfered with cholinesterase, direct high-density lipoprotein cholesterol, glucose, elevated carbon dioxide alkaline phosphatase, and alanine aminotransferase. A negative deviation of γ-GGT by hemoglobin was described in the manufacturer's statement, but our test data showed a positive deviation by hemolysis. The hemolytic threshold verification results of the other biochemical indicators were consistent with the manufacturer's statement. CONCLUSIONS: The hemolytic index test function was used to determine which samples were interfered with by hemolysis to make an analytical judgment according to the hemolytic interference thresholds of the different test items, verify the validity of the hemolytic thresholds of the test items, perform reasonable tests on the hemolytic samples, and issue valid reports to reduce the rejection rate of the hemolytic samples, shorten the turnaround time (TAT) of laboratories.

Establishment of dry chemistry based reference intervals of renal function test parameters for the adult population of Kaski District, Nepal.

BACKGROUND: Reference intervals (RIs) for clinical chemistry test parameters are specific to the method of measurement and population under service. However, there has been no locally available dry chemistry based RIs for the Nepalese population. Thus, the present study aimed to establish dry chemistry based RIs for sodium, potassium, urea, and creatinine specific to adult populations of Kaski districts, Nepal METHODS: This was a cross-sectional study conducted at the Manipal Teaching Hospital, Pokhara, Kaski, Nepal on 360 healthy adult participants aged 18-65 years. The test parameters under study were analyzed using a fully automated OCD Vitros 350 dry chemistry analyzer following the protocols provided by the reagent kit manufacturer. The RIs were estimated using reference limits at 2.5th and 97.5th percentiles. The normal distribution of the data was tested by Kolmogorov-Smirnov, and Shapiro-Wilk tests. The differences between males and females RIs were compared by the Mann-Whitney test while age-specific RIs for each sex was compared by One-Way-ANOVA and Dunnett's Multiple Comparisons Tests. All the data were managed and analyzed using MS Excel and SPSS version 20. RESULTS: The RIs of urea, creatinine, sodium, and potassium specific to the adult population of Kaski district, Nepal are as follows: urea: 4.20-13.70 mmol/L (males: 4.70-13.99; females: 4.20-13.23); creatinine: 44.20-106.10 µmol/L (males: 48.82-106.10; females: 35.40-83.78); sodium 135-146 mmol/L (males: 135-146; females: 135-146) and potassium 3.60-5.10 mmol/L (males: 3.54-5.0; females: 3.60-5.10). These RIs were found to be different from currently used RIs provided by the reagent manufacturer. RIs of all the test parameters were significantly influenced by the age of the study participants. However, only the RIs of urea, creatinine, and potassium were significantly influenced by sex. CONCLUSIONS: The present study has for the first time established dry chemistry based RIs for selected renal function test parameters specific to the adult population of Kaski district, Nepal. This result will aid the clinician in minimizing the errors in result interpretation and making a precise clinical decision.

Dipstick analysis of urine chemistry: benefits and limitations of dry chemistry-based assays.

Urinalysis is a commonly utilized laboratory test, and analysis of urine has been studied and used since ancient times. Urine contains a wide array of metabolites that can provide information regarding the current physiologic state of the body and clinical manifestations of disease. In this review, we discuss the mechanics of the dry chemistry component of the urine dipstick such as the reaction principles underlying various assays and potential effects of collection and storage on results. Additionally, we discuss the benefits and limitations of the urine dipstick as it pertains to its use as a low-cost tool in point-of-care settings and the reasoning for a lack of its use as a broad screening tool.

Comparisons of metabolite profile from paired serum and ethylenediaminetetraacetic acid-plasma samples using dry chemistry technology: An emergency department perspective.

BACKGROUND: No data is available evaluating the difference in serum versus plasma sample assay of commonly tested parameters in the emergency department, where the sample processing time can be significantly reduced if plasma is used for analysis instead of conventionally used serum. Hence, this study aimed to evaluate the differences in serum versus plasma sample estimation of commonly evaluated biochemical parameters using dry chemistry technology. MATERIALS AND METHODS: Paired blood samples were collected from a single venipuncture of 405 patients admitted to the emergency department. Dry chemistry autoanalyzer (Vitros-350, Ortho Clinical Diagnostics) was used to process all the samples. RESULTS: Data from 401 patients were analyzed. Percentage differences between serum versus plasma samples for all analytes ranged from 0.0% to 57.44% and were <±4% for a majority of parameters, except uric acid (-6.25%), albumin (+11.90%), chloride (-5.05%), phosphorus (-6.06%), creatine phosphokinase (CPK) total (-57.44%), amylase (-37.53%), lipase (-42.74%), lactate dehydrogenase (LDH) (-8.53%), and C-reactive protein (-7.44%). For albumin, CPK total, amylase, and lipase, the difference between serum and plasma samples was more than the accepted upper range recommended by College of American Pathologists. CONCLUSION: Glucose, urea, creatinine, bilirubin, total protein, serum glutamate-pyruvate transaminase, total cholesterol, high-density lipoprotein cholesterol, triglycerides, sodium, and CPK-mb can be reliably assayed from either serum or plasma samples in emergency/routine practice. CPK total, amylase, and lipase should always be assayed from serum and not plasma due to significant variations. Uric acid, chloride, phosphorous, and LDH only in emergency situations should be assayed from plasma. For routine assays, serum should be preferred.

[The significance of detection of nitrites in oral fluid of healthy people.]

The nitric oxide is a signal molecule in human organism characterized by a wide spectrum of biological effects. The exogenous nitric oxide is formed from food nitrates received with such green leafy vegetables as spinach, parsley, sorrel and also beet, cucumbers and tomatoes. The bacteria in oral cavity metabolize received with food nitrates up to nitrites. The nitrites as some intermediate metabolites of nitric oxide sufficiently exact reflect concentration of nitric oxide. The purpose of study is to examine analytical dependence and efficiency of express-device for detecting nitrites in saliva. The article presents the results of confirmation of testsystem for half-quantitative detection of content of nitrites in saliva. The device represents a hollow tube with a sensorial element within functioning by the principle of "dry chemistry". The concentration of nitrites in oral cavity was measured in 100 healthy people of both genders aged from 16 to 45 years. In case of consuming vegetables every day or 3-5 times a week higher levels of nitrite-anions (14,9-15,7 mg/l) are registered than in case of consuming vegetables and juices 1-2 times a week and rarely (9,9 mg/l). The concentrations of nitrites in saliva both in cases of regular training and low-activity life-style are within the limits of standards (11,9-14,9 mg/l). The average level of nitrites in saliva of participants of experiment with normal pressure made up to 16.5 mg/l that is significantly higher than in individuals from groups with increased and decreased arterial pressure (10,2 and 10,4 mg/l correspondingly).

Analytic and quality control validation and assessment of field performance of a point-of-care chemistry analyzer for use in the White rhinoceros.

BACKGROUND: A chemistry point-of-care analyzer would be useful for evaluating injured wildlife, particularly White rhinoceros (Ceratotherium simum) that survive poaching attempts. The IDEXX VetTest could be suitable, but species-specific validation, development of a statistical quality control (QC) strategy, and evaluation under field conditions are necessary. OBJECTIVES: The objectives were to (1) validate the VetTest for the White rhinoceros, (2) perform QC validation on the VetTest and generate a statistical QC strategy, and (3) apply this QC strategy to monitor performance under typical field conditions. METHODS: Differences between White rhinoceros heparin plasma and serum, short-term imprecision, and reportable range using rhinoceros plasma and long-term imprecision using commercial quality control material (QCM) were assessed against prescribed total allowable error (TEa ) for up to 15 analytes. Quality control validation was performed using data from the long-term imprecision study and TEa . A QC strategy using QCM was developed and used to monitor performance under field conditions. RESULTS: Imprecision was acceptable for all analytes except for ALP, ALT, and AST at low activities. The reportable range for AST and LDH differed from the manufacturer's specifications. Eleven analytes were suitable for statistical QC using the 13s rule, 3 using the 2s rule; ALP was not suitable. In the field, observed error was < TEa for all 15 analytes and the sigma metric was > 3.0 for 12 analytes. CONCLUSIONS: The VetTest is suitable for use in the White rhinoceros. Statistical QC is possible for most analytes and useful for evaluation of field performance.

[The development of express-test for semiquantitative detection of thiocyanate ions in saliva.]

The article presents the results of approbation of the express test-system for semi-quantitative detection of content of thiocyanate ions in saliva as markers of tobacco smoking. The device corresponds to hollow tube with sensory element inside functioning on the principle of "dry chemistry". At saliva intake, the analyzing component (thiocyanate ion) interacts with reagents of sensory element with formation of colored thiocyanate complex. The intensity of color of formed complex permits to judge about content of thiocyanates in saliva by comparison with standard scale. The concentration of of thiocyanate ions in oral fluid of 100 health people of both genders aged from 16 to 45 years was analyzed. The questionnaire survey of respondents was carried out to establish smoking and non-smoking contingents. The analysis established that 30% were active tobacco smokers. The everyday smokers made up to 50% out of them, non-regular smokers (several cigarettes per week or month) - 50%. The reliable relationship between intensity of smoking and concentration of thiocyanate ions in saliva is established. The level of thiocyanate ions in saliva is significantly higher (2.5 mmol/l) in the group of everyday smokers than in saliva of non-smokers of periodically using tobacco articles (0.3-0.5 mmol/l) The increased concentrations of thiocyanate ions in saliva (≥ 1,5 mmol/l) were established in 7% of nonsmokers and are possible related to consumtion of food containing glucosinolates. The test is efficient for detecting smokers using from 1 to 10 cigarettes per day. However, it is of no use in case of sporadic type of smoking.

Evaluation of the effect of ALT activity on blood donors in Guangzhou Blood Center / 中国输血杂志

Objective To understand and to grasp the basic situation on blood donors who were ineligible by ALT dry chemistry testing before blood donation.Methods The ALT rejection ratios used in initial screening and not used in two blood collection point were compared at the same time.The relativity between the dry chemistry testing and rate method were compared.An association was explored in various influencing factors on the activity of ALT.Results The use of ALT initial screening in blood donation had a significantly lower unqualified rate than not using it in early screening (P＜0.05).Dry chemical,biological method and the results had good correlation rates (r=0.993,P＜0.05).The B MI,drinking,sleeping,sports,diabetes,liver disease were independent factors affecting ALT activity (P＜0.05).Conclusion ALT initial screening can significantly reduce the unqualified rates and disposal of blood.

Establishment of reference intervals of dry chemistry tests among healthy population in Chengdu / 国际检验医学杂志

Objective To establish the reference intervals of 20 dry biochemical items in different age periods among healthy population in Chengdu to providing better support and service for clinical diagnosis and treatment .Methods The stratified random‐ized cluster method was used to collect healthy children and adults in 4 age periods(1 month-3 years old ,>3-7 years old ,>7-18 years old and >18 years old) .Totally 1 495 healthy people (740 males and 755 female) were screened out as the research sub‐jects by the questionnaire ,physical examination and laboratory screening .Fasting venous blood samples were collected from these cases ,then the VITROS 5600 dry biochemistry analyzer was used to detect 20 biochemical items .The obtained results were statisti‐cally analyzed .Results In different groups according to sex and age ,except the conjugated bilirubin (BC) was constant 0 μmol/L , the other items had statistical differences (P<0 .05) .After merging the different groups without statistically significant difference , the obtained reference intervals had significant differences compared with the reference intervals provided by the manufacturer .Con‐clusion Laboratory should establish the different reference intervals aiming at different age and gender populations according to the special character of hospital visiting populations in order to meet the clinical requirements .

Performance verification of lactate dehydrogenase in Johnson Vitros 5 .1 FS biochemical analyzer / 国际检验医学杂志

Objective To study the performance verification of lactate dehydrogenase(LDH) in the Johnson Vitros 5 .1 FS bio‐chemical analyzer .Methods According to CLSI instrumentation evaluation standard and referring to the validation scheme provided by the Johnson company ,the precision ,accuracy ,linear range of LDH ,maximum dilution degree ,biological reference range were verified .Results The LDH intra‐batch and inter‐batch precision experiments were≤3 .30% ;the accuracy experiment≤4 .00% ;the determination coefficient of the linear experiment was 0 .997 2 ;the LDH maximum dilution degree was 8 times with saline solution dilution;the biological reference range experiment verified that the reference range 313-618 U/L provided by the VITROS Meth‐odology Manual could be quote .Conclusion The performance verification of LDH detected by the Johnson Vitros 5 .1 FS biochemi‐cal analyzer basically conforms to the requirements of the quality objectives and manufacturer′s instructions ,and meets the needs of clinical test .

Influence of Vaginal Discharge on Dry Chemistry Determination of Leukocyte Esterase in Female Urine / 现代检验医学杂志

Objective The present study is to investigate the influence of vaginal discharge on dry chemistry determination of leukocyte esterase in female urine.Methods Collected 20 and 30 normal vaginal discharge samples.Which humoral routine test degree were Ⅰ and Ⅱ correspondingly,and then analyze leukocyte esterase and squamous epithelial cells in these normal vaginal discharge samples.Collected normal vaginal discharge samples again and isolate the vaginal squamous epithelial cells from those normal vaginal discharge samples.Made two concentration of squamous epithelial cell suspension liquid (20/μl and 60/μl)and added these liquid.To normal female urine and analyze the drying chemical leukocyte esterase in those urine. Cleaned the vulva of those patients with normal leukocyte counts in urine sediment determination,whose dry chemical deter-mination of leukocyte esterase was strong positive,perform the routine urine test with her middle urine.Results The results of the determination of leukocyte esterase in normal vaginal discharge samples were 66.7% positive.And there were ~squamous epithelial cells in all samples (microscopy).No significant difference was observed in the examination of dry chem-istry leukocyte esterase among the normal female urine group,low (20/μl)and high (60/μl)concentrations of squamous epi-thelial cell urine group (P >0.05).The counts of squamous epithelial cells and the rate of positive and intensity of dry chem-ical leukocyte esterase in the middle of second urine were significantly lower than before,and the differences are statistically significant (P <0.05).But there was no significant difference for leukocytes counts.Conclusion Urine squamous epithelial cells had no influence on the detection of leukocyte esterase by dry chemistry.However,the leukocyte esterase in the vaginal discharge greatly influenced the examination of the leukocyte esterase in urine.

Comparison of the Reference Intervals of 2 3 Analytes between Wet Chemistry and Dry Chemistry in 2 3 1 Clinical Laboratories in China / 现代检验医学杂志

Objective To compare the current application status of reference intervals in dry chemistry to the reference inter-vals of anlytes of wet chemistry in the same hospital.Methods By using web-based external quality assessment (EQA) software system,collecting the submitted data from the laboratories which attended national reference intervals investigation of reference intervals of analytes in dry chemistry and wet chemistry,using professional statistical software for analyzing the data,including paired-samples t test and Yates’Chi-square test.Results 231 laboratories submitted their investigation re-sults including the reference intervals of 23 analytes of dry and wet chemistry.69.6% (32/46)of reference intervals of ana-lytes in dry chemistry have significant statistical differences compared with the wet chemistry in paired-samples t tests. 80.4% (37/46)of medians of reference intervals of analytes in dry chemistry had significant statistical differences in loca-tions and distributions compared with medians of reference intervals of wet chemistry in the same institute.Conclusion The reference intervals of analytes of dry chemistry have differences compared with the wet chemistry in the same hospital.The medians of reference interval’s lower and higher limits of dry and wet chemistry have difference in locations and distribu-tions.Proposed to create our own reference intervals of dry chemistry in China.

Combination of urine sediment quantitative analyzer and urine dry chemistry analyzer in detection of urine cell / 国际检验医学杂志

Objective To evaluate the efficacy of IQ200 urine sediment quantitative analyzer(IQ200) and Mejer700 urine dry chemistry analyzer(Mejer700) in detecting urine erythrocyte(RBC)and leukocyte(WBC) .Methods The WBC and RBC in 1 000 u‐rine specimens were detected by using IQ200 ,Mejer700 and sediment microscopy respectively .Taking sediment microscopy as the golden standard ,the sensitivity ,specificity and accuracy of IQ200 and Mejer700 in detecting urine RBC and WBC were analysed .Re‐sults No statistically significant differences of positive rates of RBC and WBC detected by using the three methods were found (P>0 .05) .When IQ200 and Mejer700 were combined ,the sensitivities of detection of RBC and WBC test were improved .Conclu‐sion The sensitivities of RBC and WBC detection by using IQ200 and Mejer700 are high .Combing the two methods the sensitivity and accuracy is higher ,which could improve work efficiency .Combination of the three methods should be recommended ,in order to improve the quality of urine analysis .

Analytical performance of a dry chemistry analyzer designed for in-clinic use.

BACKGROUND: The Heska Dri-Chem 4000 uses dry slide technology to evaluate serum or plasma. No previous independent performance evaluation is published to the authors' knowledge. OBJECTIVES: The objectives were to (1) characterize analytical performance of a Dri-Chem 4000 by measuring precision and bias, (2) compare analytical performance of that Dri-Chem 4000 unit with a predetermined quality requirement, and (3) determine whether statistical QC of the Dri-Chem 4000 is possible using the 13s control rule. METHODS: Sixteen analytes were measured using plasma from dogs, cats, and horses. Coefficient of variation (CV), bias, and observed total error (TEobs ) were calculated. TEobs was compared with allowable total error (TEa ). Sigma metric and quality goal index were calculated where relevant. QC validation was performed. RESULTS: Bias and TEobs calculated using quality control material (QCM) data were smaller than those calculated using method comparison data. Using TEobs calculated from species-specific CV and QCM-based bias, 100% of analytes in each species met ASVCP-recommended TEa . Desired error detection and false rejection rates were achievable using the 13s control rule and ASVCP-recommended TEa values for 9/16 (56%) of analytes in dogs, 9/14 (64%) of analytes in cats, and 8/13 (62%) of analytes in horses. CONCLUSIONS: Analytical performance of the Dri-Chem 4000 is comparable to that reported by other authors for other small benchtop biochemistry analyzers. Statistical QC using a simple control rule is possible for most analytes in dogs, cats, and horses.

Study on consistency of urinary sediment analyzer,urine dry chemistry analyzer and optical microscope in detecting urine erythrocyte / 国际检验医学杂志

Objective To analyze the consistency of the SYSMEX UF1000i automatic urinary sediment analyzer,Arkray AX-4030 urine dry chemistry analyzer and optical microscope in detecting urine erythrocyte.Methods The fresh urine specimens from 427 patients were randomly extracted and tested by the SYSMEX UF1000i automatic urinary sediment analyzer,urine dry chemistry analyzer and OLUMPUS Arkray AX-4030 optical microscope.Then the consistency of the results for detecting urine erythrocyte was compared among three kinds of detection method.Results With the microscopic examination as control,the sensitivity and spe-cificity of the SYSMEX UF1000i automatic urinary sediment analyzer for detecting urine erythrocyte were 82.84% and 86.35% re-spectively,which of the Arkray AX-4030 urine dry chemistry analyzer were 89.55% and 83.96% respectively.There was a high consistency between the SYSMEX UF1000i automatic urinary sediment analyzer and the optical microscope for detecting urine e-rythrocyte and the Kappa value was 0.580.There was also a high consistency between the Arkray AX-4030 urine dry chemistry analyzer and the optical microscope for detecting urine erythrocyte and the Kappa value was 0.625,while the consistency between the SYSMEX UF1000i automatic urinary sediment analyzer and the Arkray AX-4030 urine dry chemistry analyzer was weaker and the Kappa value was 0.324.Conclusion With the detection by the SYSMEX UF1000i automatic urinary sediment analyzer and the Arkray AX-4030 urine dry chemistry analyzer as a screening test,it should need to combine with the optical microscopy to conduct recheck for providing the effective and reliable test results quickly and accurately.

Application evaluation of HC-900 urine analyzer for rapidly screening urine microalbumin / 国际检验医学杂志

Objective To evaluate the clinical application value of the HC-900 fully automated urine dry chemistry analyzer and its matched test strip (HC-900 analysis system) for detecting urine microalbumin (U-mAlb) .Methods 660 urine samples were collected with the negative urine protein detected by the HC-900 analysis system as the standard ,among them ,159 samples with positive U-mAlb screened by the test strip and 106 samples with the partial negative were performed the quantitative analysis by the Immage 800 fully automatic specific protein analyzer for verifying the results screened by the HC-900 analysis system .The compari-son of the U-mAlb quantitative detection results between the screening positive group and the screening negative group adopted the two samples rank sum test .The comparison between the enumeration data was carried out by Kappa test for consistency .Results Among 660 samples ,159 samples with positive U-mAlb were quantitatively detected by the Immage 800 analyzer and 101 samples were confirmed positive U-mAlb with the real positive rate of 63 .5% .Among 106 samples of negative U-mAlb randomly extracted by the HC-900 analysis system ,9 samples were confirmed to be positive U-mAlb quantitatively detected by the Immage 800 analy-zer .By the consistency test ,the difference between the two methods had statistical significance (Kappa=0 .495 ,P<0 .01) .The U-mAlb level was 18 .02(8 .23-34 .89)mg/L in the screening positive group ,which was significantly higher than 4 .78(2 .51-8 .46) mg/L in the screening negative group ,the difference had statistical significance (Z= -8 .689 ,P<0 .01) .Relative to the detection by the Immage 800 quantitative analyzer ,the sensitivity and specificity of the U-mAlb for the rapid screening by the dry chemistry method was 91 .8% (101/110) and 62 .5% (97/155) respectively .Conclusion The HC-900 analysis system for screening U-mAlb has a certain clinical application value .

Avaliação da interferência do ácido ascórbico na detecção da glicosúria / Evaluation of ascorbic acid interference in the detection of glycosuria

INTRODUÇÃO: O ácido ascórbico (vitamina C) é comumente ingerido como suplemento vitamínico. É uma vitamina hidrossolúvel, excretada pela urina e pode interferir nos ensaios laboratoriais, como nas reações de oxirredução para detecção da glicosúria. OBJETIVO: Este trabalho tem como objetivo avaliar a interferência do ácido ascórbico na detecção de glicosúria pelo método de química seca por meio do uso de tiras reagentes. MATERIAIS E MÉTODOS: Amostras de urina foram avaliadas no analisador da marca Clinitek Atlas (Siemens Healthcare Diagnostics Inc., EUA). Foram selecionadas quatro amostras de urina com diferentes concentrações de glicose: 100 mg/dl, 250 mg/dl, 500 mg/dl e 1.000 mg/dl. Para cada concentração de glicose foram criadas cinco alíquotas, adicionando-se uma solução de ácido ascórbico 200 mg/dl, suficiente para obter uma concentração final de ácido ascórbico de 20 mg/dl no primeiro tubo, de 50 mg/dl no segundo tubo, de 270 mg/dl no terceiro tubo, de 1.000 mg/dl no quarto tubo e de 2.000 mg/dl no quinto tubo. Após essa adição, as amostras foram novamente avaliadas no analisador Clinitek Atlas. RESULTADOS: Nas amostras com concentração de 20 mg/dl de ácido, não se evidenciou interferência. Nas concentrações iguais e acima de 50 mg/dl, a interferência do ácido ascórbico se fez presente, sendo que o fato foi caracterizado pelos resultados falso negativos para detecção da glicose urinária. CONCLUSÃO: Os resultados demonstraram a interferência do ácido ascórbico no método da química seca (tiras reagentes), subestimando o nível de glicose urinária.

INTRODUCTION: Ascorbic acid (vitamin C) is commonly used as a vitamin supplement. It is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. OBJECTIVE: This study aims to assess ascorbic acid interference in glycosuria detection by dry chemistry method (reagent strips). MATERIAL AND METHODS: Urine samples were evaluated by using Clinitek Atlas chemistry analyzer (Siemens Healthcare Diagnostics Inc., USA). Four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. After the addition of ascorbic acid, the samples were reassessed by using Clinitek Atlas chemistry analyzer. RESULTS: There was no interference at concentrations of 20 mg/dl. However, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. CONCLUSION: The results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips) inasmuch as it underestimates urinary glucose levels.