Qualitative Reagent Research Articles

Performance analysis among multiple fully automated anti-SARS-CoV-2 antibody measurement reagents: A potential indicator for the correlation of protection in the antibody titer

BackgroundTo evaluate the performance of various reagents in automated analyzers for antibody detection against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). MethodsUsing 100 serum samples from 100 individual patients diagnosed with SARS-CoV-2 infection, the precision, linearity, determination agreement, and correlation of five qualitative reagents (Elecsys Anti-SARS-CoV-2, ARCHITECT SARS-CoV-2 IgG, ARCHITECT SARS-CoV-2 IgM, Access SARS-CoV-2 IgM, and SARS-CoV-2 IgM) and four quantitative reagents (Elecsys Anti-SARS-CoV-2 S, ARCHITECT SARS-CoV-2 IgG II, Access SARS-CoV-2 IgG 1st IS, and SARS-COV-2 IgG S) were analyzed. A surrogate virus-neutralizing test (sVNT) kit was used to evaluate the measurement value of each quantitative reagent corresponding to the amount of neutralizing antibody, similar to that of patients in the late stage of infection. ResultsPrecision and linearity were found to be sufficient for clinical use. Five discrepant samples were observed in the positive and negative judgments of the qualitative reagents for IgG, and one discrepant sample was observed in the qualitative reagent for IgM. Although the measurement values of the quantitative reagents were different, they were correlated with each reagent. The reference values inferred from the sVNT were Elecsys Anti-SARS-CoV-2: 71.8 U/L, ARCHITECT SARS-CoV-2 IgGⅡ: 2976.3 AU/mL, Access SARS-CoV-2 IgG 1st IS: 689.6 IU/mL, and SARS-CoV-2 IgG S: 19.3 U/L. ConclusionsThe performance observed for each anti-SARS-CoV-2 antibody detection reagent was sufficient. The reference values based on the inhibition rate of sVNT have potential as indicators of the correlation of protection and are expected to be leveraged in automated antibody tests.

M060 Evaluation of the cutoff for major AFP qualitative reagents in Korea

M060 Evaluation of the cutoff for major AFP qualitative reagents in Korea

Analyses of the Proficiency Testing Program and the Performance of Qualitative Reagents for Rheumatoid Factor

Analyses of the Proficiency Testing Program and the Performance of Qualitative Reagents for Rheumatoid Factor

Evaluation of quantitative and qualitative fecal occult blood reagent in colorectal cancer screening

Objective To investigate the application effects of quantitative and qualitative fecal occult blood (FOB) reagent in colorectal cancer screening.Methods With the platform of colorectal cancer screening for early diagnosis and treatment,the original screening methods and process were not changed,individuals underwent colorectal cancer screening,aged from 40 to 74 years old,from four villages of Haining City in Zhejiang Province were selected as study objects.Initial screening included medical history questionnaire and FOB test.The first stool samples were examined both with quantitative and qualitative FOB test,one week later the second samples were detected with qualitative FOB test.History positive or once of any type of reagent positive was considered as initial screening positive.The individuals with initial screening positive received fine screening (colon endoscope examination).The effects evaluation included the positive rate of FOB,intestinal lesion detection rate,sensitivity,specificity and Youden index.The health economic analysis was calculated.Chi-square test was performed for comparisons between the two groups.Results A total of 8 427 history survey were completed,the positive rate of history was 8.48％(715/8 427) ; 6 644 underwent quantitative detection of FOB and the positive rate was 4.44 ％ (295/6 644) ; qulitative test was conducted in 12 633 samples were conducted and the positive rate was 2.56 ％ (324/12 633),the difference was statistically significant (x2 =49.27,P＜ 0.01).A total of 854 individuals with initial screening positive underwent electronic colonoscopy examination,the total intestinal lesion detection rate was 22.72％ (194/854),of which the intestinal lesion detection rate of quantitative group was 34.55％ (66/191),and that of qualitative group was 17.73％ (36/203),the difference was statistically significant (x2 =14.53,P＜0.01).The detection rate of both quantitative and qualitative test positive was 43.75 ％ (14/32).The colorectal cancer detection rates of quantitative and qualitative FOB test were 3.66％ (7/191) and 0.99％ (2/203),advanced adenoma detection rates were 8.38 ％ (16/191) and 5.91％,there were no significant differences (x2 =2.08 and 0.96,both P＞0.05).The sensitivity of quantitative and qualitative FOB test in advanced adenoma and cancer detection rate was 45.10％ and 27.45％,respectively.The average cost of quantitative and qualitative FOB test in intestinal lesions detection was 5 874.50 and 1 432.14 yuan.Conclusion The effects of quantitative FOB test in colorectal cancer screening was better than that of qualitative reagent,however on the cost of screening,the former was 4.10 times of the latter. Key words: Colorectal neoplasms; Mass screening; Feces; Occult blood; Indicators and reagents; Cost-benefit analysis

Technical requirements of the pathogen-specific Ig M qualitative detection reagents

To offer the guidance of the registration application of in vitro diagnostic (IVD) reagents,the technical requirements for registration of the pathogen-specific Immunoglobulin M (IgM) qualitative test reagents were discussed.The application paperwork including the evaluation of analytical performance was analyzed based on the the legal requirement from the China Food and Drug Administration (CFDA) and the experience of the IVD registration.(Chin J Lab Med,2013,36:947-949) Key words: Immunoglobulin M; Reagent kits; diagnostic; Indicators and reagents; Registries; Evaluation studies

Synthesis of Nanostructured Cuprous Oxide and Its Performance as Humidity and Temperature Sensor

ABSTRACT The present paper reports the synthesis of cuprous oxide particles through pathological route by using glucose solution as reducing agent in Benedict qualitative reagent. The synthesized material has been investigated by scanning electron microscopy (SEM) and x-ray diffraction studies. SEM shows uniform distribution of pores. The size of cuprous oxide particles lies in the range 25–123 nm. The pellet of cuprous oxide nanopowder has been subjected to annealing at different temperatures, 200°C, 400°C, and 600°C, and exposed to humidity. Variation in electrical resistance of pellet is almost linear with appreciable slope for 10–95% relative humidity at room temperature. Also each sensing element was exposed to different ambient temperatures and corresponding electrical resistances were recorded. The sensitivity and activation energy of sensor at various temperatures have been calculated.

A Study Of Morbidity Profile Of Elderly In Urban Areas Of North India

Geriatrics population is an important part of the total community & comprises of about 7-8% of the whole population of one community. Since the expectation of life is also increasing steadily and quality of life being emphasized more & more in our country, the senior citizen group is getting importance day by day. WHO is also concerned about the health of this group and is promoting the concept of healthy aging throughout the World. The study was conducted in 606 persons above the age of 60 years both male (322) and female (284). Joint paints & cataract occupy the top position among different morbid condition i.e. 46% and 45% respectively. Hypertension, GIT problems, Diabetes and Loneliness & depression are among the other major morbidities contributing 22%, 14.8%, 11% and 9% respectively. DEPARTMENT AND INSTITUTION WHERE THE WORK WAS DONE Urban field practice attached to Dept. of Community Medicine, Pt. B.D. Sharma PGIMS, Rohtak, India.. INTRODUCTION Geriatrics population is an important part of the total community & comprises of about 7-8% of the whole population of one community. Since the expectation of life is also increasing steadily and quality of life being emphasized more & more in our country, the senior citizen group is getting importance day by day. It is therefore very essential and desirable that the health of this group is protected and maintained to get the maximum benefits for the over all growth & development of this nation. Earlier the diseases are diagnosed and earlier they are treated, the more will be the benefits in obtaining the optimal level of positive health. The good health enjoyed by these elderly will go a long way in strengthening one health care and economy. Needless to point out that even the WHO is also concerned about the health of this group and is promoting the concept of healthy aging throughout the World. OBJECTIVES To know the common health problems in the elderly population of Rohtak town. STUDY DESIGN Cross sectional MATERIAL & METHODS The information was collected (as such) with the help of postgraduate students, interns, MPHW (M & F) & concerned Anganwari Workers through a pre designed & pre-tested proforma in the urban setting. For hypertension, sphygmomanometer was used taking 140/90 mm of Hg as cut out limits and for diabetes simple urine testing was done using Benedict's qualitative reagent and graded accordingly. Cataract was diagnosed with the help of a torch & differentiated into Mature Senile Cataract & Immature Senile Cataract. Hearing loss was assessed by taking history of the subjects. In cases of loneliness and depression the history of spouse was also taken. PARTICIPANTS & SETTINGS 606 persons above the age of 60 years both male (322) and female (284) were included in the study who were selected randomly from a population of about 23000 with the help of Anganwari Survey Register. There were 1854 elderly subjects in about 4600 families coming 23096 urban slum populations. The elderly population was enlisted in the study covering 606 elderly subjects both males & females.

Historical survey of the uses of organic compounds as reagents in analytical chemistry

Early developments in the use of organic substances as analytical reagents are reviewed. Natural materials of plant and animal origin were exclusively used as indicators and qualitative reagents in the 17th and 18th centuries, but were gradually superseded by synthetic products as organic chemistry matured during the 19th century. The development of the Griess test for nitrous acid, including Warington's and Ilosvay's modifications, is outlined. The early applications of purified natural products, such as the alkaloids, and of several sulphur-containing compounds are also discussed.Finally, the classic chelate-forming reagents for metals, such as copper, cobalt, iron and nickel, are viewed in their historical context as contributing to the development of selective and sensitive analytical reagents.

Simple fluorometric determination of aldosterone in urine without use of isotopes or chromatography.

Aldosterone 18-glucuronide in urine is hydrolyzed by adjusting the pH to 1.0 and allowing the mixture to stand overnight at room temperature. The free aldosterone is then extracted into dichloromethane, which is washed with carbonate to remove acidic compounds and evaporated. The residue is partitioned between a nonpolar organic phase and an aqueous phase, and the aldosterone oxidized to the 13-carboxylic acid derivative with Benedict's qualitative glucose reagent. Neutral compounds are extracted from this oxidation mixture with dichloromethane at pH 7.5, the mixture is acidified, and the oxidized aldosterone extracted into dichloromethane. After washing with pH 3.5 buffer, this extract is evaporated and the oxidized aldosterone determined fluorometrically via a two-stage reaction with sulfuric acid/water (85/15 by vol) and methanol containing ferric chloride.

Selective detection of bismuth(III) and iron(II) ions with certain new reagents

Isoperthiocyanic acid (3-amino-5-thione-1,2,4-dithiazole) (I), tetraethylthiuram monosulphide (“Tetmosol”) (II), eosin (III), and mercurochrome (IV) are used as new qualitative reagents for bismuth, III and IV are also used for detection of iron(II). A conc. sulphuric acid solution of I, or an acctone solution of II, when treated with bismuth in presence of potassium iodide, gives a deep red or reddish-orange precipitate, characteristic of bismuth. Bismuth in presence of III or IV gives a heavy and characteristically bright deeppink precipitate on addition of ammonia. With I, 1 μg of bismuth may be detected with a dilution limit of 1:50,000. Sb(III) and As(III) do not interfere in any of these tests. Iodides interfere only when I and II are used as reagents. Pb, Cu(II). and Fe(III) interfere with III and IV. I and II are also proposed as reagents for iodide; nitrites would interfere. III and IV, with iron(II) on addition of ammonia, produce a precipitate with highly intense green fluorescence. No other common cation [including Fe(III)] or anion interferes. The limit of detection is 3 μg ml .

A reassessment of rhodizonic acid as a qualitative reagent

Rhodizonic acid has been re-examined as a qualitative reagent, and it has been shown that it will react with many metals to give characteristic spectra if the dielectric constant of the solvent is sufficiently low and if a protective colloid is added. The range of application of rhodizonic acid has been considerably extended in this way.

Some Volatile Components in Milk, Blood, and Urine from Cows Fed Silage, Bromegrass, and Hay and Grain1,2

Summary Chromatographic analyses of volatile material in milk, blood, and urine of cows fed silage, bromegrass pasture, and a control ration of hay and grain were made. Off-flavors as determined by organoleptic analysis could not be related to any specific volatile materials determined from the analyses. Of the volatile constituents found in biological fluids, their concentrations were usually higher in urine than either milk or blood. Some chromatographic peaks from the analysis of some of the biological fluids were peculiar to certain feeds. Evidence for identification was presented for ethyl ether, ethanol, methyl sulfide, propanal, acetone, methanol, 2-butanone, 2-pentanone, and n-propanol. Identification was based upon agreement of retention time with known compounds and alteration of chromatographs by prior treatment of samples with various qualitative reagents. Of materials observed, only acetone and 2-butanone were conclusively identified.

Iodide ion as a qualitative reagent: Detection of nitrite and sulfite

Iodide ion as a qualitative reagent: Detection of nitrite and sulfite

A new qualitative reagent for aluminum. A specific qualitative reagent for copper

A new qualitative reagent for aluminum. A specific qualitative reagent for copper

Gas Chromatographic Analysis of Head Space Gas of Dilute Aqueous Solutions.

Enrichment of head space gas in sulfides, carbonyls, esters, and alcohols prior to chromatographic analyses was accomplished by adding anhydrous sodium sulfate salt to dilute aqueous solutions. It was possible to analyze head space gas from aqueous solutions below the 1 p.p.m. level. In addition to retention times, evidence for identification of these trace organic compounds was obtained by eliminating peaks with selective qualitative reagents. Evidence for the identification of the 18 components of a complex mixture of sulfides, carbonyls, esters, and alcohols at the 1 p.p.m. carbonyls was made to establish the limits of sensitivity of the method.

O-Diamines as reagents for selenium : Part I. 4-dimethylamino-1,2-phenylenediamine

4-Dimethylamino-1,2-phenylenediamine is investigated as a photometric and qualitative reagent for selenium. With this reagent selenium (IV) forms 5-dimethylamino-2,1,3-benzoselenadiazole, a red colored compound, with an absorption maximum in the visible region at 500 mμ. Variables such as reagent stability, extinction stability, reaction rate, influence of acidity, foreign ions, validity of Beer's law are discussed. The reagent is highly selective for selenium, has good sensitivity and recproducibility, and is also useful for qualitative purposes.

A specific qualitative reagent for copper

Suggests the use of T-sulfonamidine as a specific precipitant for the separation and confirmation of copper(II) ions.

A new qualitative reagent for aluminum

A new qualitative reagent for aluminum

Studies on the Analytical Applications of Onium Compounds. I

Tetramethylammonium iodide, (CH3)4NI, is synthesized and its behaviors on Bi+++, Sb+++, Pb++, and Hg++ are investigated polarographically; the reaction in the presence of iodide ion gives a characteristic red orange precipitate, but no precipitate is formed in the absence of iodide ion. The mechanism of this reaction is considered to be due to the formation of complex anions, e. g. BiI4-, SbI4-, PbI4--, and HgI4-- from reaction of I- in (CH3)4NI with various metal ions, and the precipitate is formed from reaction of these complex anions and tetramethylammonium ion, (CH3)4N+, among which the reaction of the reagent with bismuth complex ion is especially sensitive as a good qualitative reagent since it can be detected within the limit of several tenth γ, while the precipitate with other metal ions have comparatively large solubilities and unsuitable for either qualitative or quantitative reagent. Polarograms of each case are given and discussed

Benzoin as Fluorescent Qualitative Reagent for Zinc

Benzoin as Fluorescent Qualitative Reagent for Zinc