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At least 1,099 records · Page 61Linked to original sources
PubMed1995

Evaluation of a novel serotyping system for hepatitis C virus: strong correlation with standard genotyping methodologies.

Direct sequencing and analysis of viral genomes are definitive methods for identifying various hepatitis C virus (HCV) genotypes. However, HCV genome sequencing methods are cumbersome and unsuitable for analyzing large numbers of clinical samples. We have developed a convenient, reliable, and reproducible RIBA strip immunoblot assay system for determining HCV serotype. Briefly, the assay consists of an immunoblot strip on which there are five lanes of immobilized serotype-specific HCV peptides from the nonstructural (NS-4) and core regions of the genomes of HCV types 1,2, and 3. HCV serotype is deduced by determining the greatest intensity of reactivity to the NS-4 serotype-specific HCV peptide band in relation to the intensity of the human immunoglobulin G internal control bands on each strip. HCV core peptide reactivity is used only in the absence of NS-4 reactivity. We used this assay to successfully serotype a high percentage of sera from well-documented HCV-infected patients. Our serotyping results correlated 99% with the findings from the standard restriction fragment length polymorphism genotyping methods. Less than 5% of the serum samples were untypeable. For a selected group of alpha interferon-treated patients we observed that the nonresponders (76.2%) and a majority of the responders who relapsed (72.2%) had type 2 HCV infection. A small population (n= 8) of complete responders was split 3:4:1 as type 1, type 2, and type 3, respectively. Our data indicate that this new serotyping assay has the potential to be a highly specific and reliable method for typing of HCV infection in patients.

Genotype↗
PubMed1982

Diamine oxidase in the diagnosis of ruptured fetal membranes.

Diamine oxidase activity is present in amniotic fluid but absent from vaginal secretions, providing a method for diagnosing rupture of membranes. Vaginal secretions were absorbed onto sterile paper strips, eluted, and assayed for diamine oxidase activity. Interfering substances included maternal serum, iodine antiseptics, and large amounts of meconium. Two of 109 prenatal clinic (negative control) specimens displayed measurable diamine oxidase activity; one of 144 postamniotomy (positive control) specimens had no diamine oxidase activity. Of 75 test specimens obtained by speculum examination and 488 test specimens obtained without the aid of a speculum, 18 and 62, respectively, displayed a diamine oxidase test result different from results of conventional tests (nitrazine paper, ferning, fetal cell stains). These discrepancies are discussed in view of the utility of the diamine oxidase test as an adjunct to conventional methods for diagnosing rupture of membranes. The diamine oxidase test appears to be objective, sensitive, quantitative, and capable of detecting amniotic fluid leaks more than 25 hours after rupture of membranes. It can be performed in 1 hour and requires a scintillation counter.

Amine Oxidase (Copper-Containing)↗
PubMed1998

Technical and clinical evaluation of an electrochemistry glucose meter: experience in a diabetes center.

The Sensorex (Metertech, Taipei, Taiwan), an electrochemical blood glucose meter, is designed for self-monitoring of blood glucose (BG) concentrations in capillary blood through the use of an electrochemical test strip. The intra-assay coefficients of variation of Sensorex were 5.2, 5.4, and 4.7% at BG levels of 46, 154 and 302 mg/dl respectively. The BG concentrations tested by Sensorex were correlated well with those by YSI method (r approximately/= 0.85, P < 0.0001). The intraclass correlation coefficients (rI) between the results obtained by Sensorex and YSI were 0.84 in capillary blood and 0.69 in venous whole blood, which indicated good agreement between both methods. The Sensorex was evaluated by error grid analysis and revealed 'acceptance' results. In field test, the Sensorex results obtained by lay users were in concordance with those by trained technicians (rI = 0.87). Our data show that the Sensorex glucometer is reliable and easy to use. We also demonstrate a practical clinical approach for the evaluation of a novel SMBG system.

Adolescent↗
PubMed1999

A comparative evaluation of Etest and broth microdilution methods for fluconazole and itraconazole susceptibility testing of Candida spp.

The Etest strip is a promising tool of broad application in clinical microbiology. The method provides MIC readings and is easier to perform than broth microdilution. We carried out a study to compare the MICs of fluconazole and itraconazole obtained by the Etest with those obtained by broth microdilution, performed according to the guidelines of the NCCLS document M27-A, with 402 clinical isolates (360 Candida albicans, 17 Candida tropicalis, nine Candida krusei, nine Candida glabrata and seven Candida parapsilosis) and seven control isolates. The agreement between MICs by the two methods (at +/- 2 dilutions) was 74.5% for fluconazole and 61.4% for itraconazole. These results suggest that further development is necessary to standardize the medium and incubation conditions before introduction of the Etest as a routine method in the clinical microbiology laboratory for fluconazole and itraconazole susceptibility testing.

AIDS-Related Opportunistic Infections↗
PubMed1990

Evaluation of the RheumaStrip ANA profile test: a rapid test strip procedure for simultaneously determining antibodies to autoantigens U1-ribonucleoprotein (U1-RNP), Sm, SS-A/Ro, SS-B/La, and to native DNA.

The "LipoGen RheumaStrip ANA Profile" test method (LipoGen, Inc.) is a new assay format for autoantibody detection in which recombinant autoantigens are used. This enzyme immunoassay, in test-strip format, detects antibodies to autoantigens U1-ribonucleoprotein (U1-RNP), Sm, SS-A/Ro, SS-B/La, and to native DNA (nDNA). We evaluated 200 antinuclear antibody (ANA)-positive and 100 ANA-negative sera for the presence of antibodies to U1-RNP, Sm, SS-A/Ro, SS-B/La, and nDNA by the new test-strip procedure. These data correlated well with those obtained with either Ouchterlony double immunodiffusion for U1-RNP, Sm, SS-A/Ro, and SS-B/La or with Crithidia luciliae indirect immunofluorescence for anti-nDNA. Assay sensitivity and assay specificity of the ANA Profile method as compared with those of established procedures were respectively as follows: 89.8% and 98.8% for U1-RNP, 86.4% and 95.3% for Sm, 97.9% and 89.3% for SS-A/Ro, 98.3% and 86.3% for SS-B/La, and 97.5% and 93.1% for nDNA. Agreement between the ANA Profile test and these other test methodologies ranged from 88.7% for the SS-B/La test to 97.3% for the U1-RNP test. This new test procedure substantially decreases the time and effort required to perform these assays. Total hands-on time and overall assay time were decreased by 72% and 97%, respectively.

Antibodies↗
PubMed2005

A simple and rapid chromatographic strip test for detection of antibody to porcine reproductive and respiratory syndrome virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be a major economic problem for swine industries worldwide despite several disease-reduction strategies such as age-segregated early weaning and all-in-all-out pig movement. Routine diagnosis of PRRSV is carried out by the combined use of an antibody-detecting enzyme-linked immunosorbent assay (ELISA), immunofluorescence, reverse transcription-polymerase chain reaction, and virus isolation. These assays require specialized laboratory equipment in addition to multistep sample handling and sample preparation. The objective of this study was to evaluate a simple pen-side assay (BioSign PRRSV) for rapid detection of PRRSV antibody based on a lateral flow chromatographic strip immunoassay system. This assay uses Escherichia coli-expressed viral nucleocapsid protein antigen for detecting antibodies against PRRSV in swine sera. In this report, the authors describe the evaluation of this assay using sera from both clinical samples and experimentally infected piglets. The results were compared with those of a standard, commercially available antibody ELISA (HerdChek PRRS ELISA) and an indirect immunofluorescence assay using the same serum samples. The BioSign PRRSV assay was capable of detecting antibodies in sera known to contain antibodies to PRRSV, resulting in 93.2% sensitivity for samples from experimentally infected pigs and 98.7% sensitivity for clinical serum samples. For sera that did not contain antibodies to PRRSV, the specificity was found to be 98.5% and 99.2% for clinical and experimental serum samples, respectively.

Animals↗
PubMed2005

Incidence of subclinical ketosis in cows supplemented with a monensin controlled-release capsule in Holstein cattle, Florida, USA.

The objective of this study was to determine the effect of a monensin controlled-release capsule on the proportion of cows with subclinical ketosis (SK). During July to August 2001, 300 cows dried-off 50-70 days before expected parturition were randomly assigned to either a treatment (n = 150, oral capsule, 335 mg/d of monesin for 95 d) or control group (no capsule, n = 150). At 14 days postpartum, a milk sample was obtained and evaluated for beta-hydroxybutyrate (BHBA) using a semi-quantitative ketone test strip. In a sub-sample of 50 cows per group a blood sample was taken and analyzed for BHBA using an ELISA kit. Milk BHBA > or = 200 micromol/L was used as the cut-off value for diagnosis of SK. The incidence of SK based on the milk test was statistically different between groups (P < or = 0.05) with a value of 26.6% for control and 14.5% for cows treated with monensin, respectively. Cows treated with monensin were 0.68 times less likely to give a positive result for milk BHBA than non-treated cows (0.53-0.80; 95% CI). Serum BHBA concentrations did not differ between groups (0.81 +/- 0.09 mmol/L versus 0.70 +/- 0.07 mmol/L for controls and treated, respectively; P > 0.05). However, for each incremental increase in serum BHBA of 0.1 mmol/L occurrence of SK increased 52% (OR = 1.52; 1.21-1.91; 95% CI).

3-Hydroxybutyric Acid↗
PubMed2002

Performance of the rapid plasma reagin and the rapid syphilis screening tests in the diagnosis of syphilis in field conditions in rural Africa.

OBJECTIVES: To assess the rapid plasma reagin (RPR) test performance in the field and to evaluate a new rapid syphilis test (RST) as a primary screen for syphilis. METHODS: 1325 women of reproductive age from rural communities in the Gambia were tested for syphilis seropositivity using a RPR 18 mm circle card and a RST strip. Within 1 week a repeat RPR and a TPHA test were carried out using standard techniques in the laboratory. RESULTS: Comparing field tests to a diagnosis of "active" syphilis defined as laboratory RPR and TPHA positive, the RPR test was 77.5% sensitive and 94.1% specific; the RST was 75.0% sensitive and 95.2% specific. The RST was easier to use and interpret than the RPR test especially where field conditions were difficult. In this setting with a low prevalence of syphilis in the community (3%), the chance of someone with a positive test being confirmed as having serologically active syphilis was less than 50% for both tests. CONCLUSIONS: The appropriateness of syphilis screening using RPR testing in antenatal clinics and health centres should be questioned if there is a low prevalence in the population, conditions for testing are poor, and resources limited. There is still an urgent need for an appropriate rapid syphilis test for field use.

Adolescent↗
PubMed1993

Evaluation of the Clinitek 200 urinary test-strip reader in the analysis of dog and rat urines in pre-clinical toxicology studies.

The performance of a clinical urinary test-strip reader Clinitek 200 was evaluated for dog and rat urines, in the context of pre-clinical toxicology studies. No major discrepancies were found between data generated by visual estimation or automatic measurement. Analysis of spiked samples showed good agreement between actual concentrations and Clinitek 200 responses for ketone bodies and glucose although a lack of sensitivity was found for the latter. Results for proteins showed over- or underestimation in dog and rat urines respectively at low concentrations, and overestimation at high concentrations in both species. Reproducibility of responses was excellent for ketone bodies, glucose and proteins but was weaker for haemoglobin and bilirubin. High bilirubin concentrations were found to interfere with the haemoglobin reaction. The pH measurements were found to be accurate only around pH 7. Specific gravity measurements were unreliable. Overall, the Clinitek 200 as a screening tool proved sufficiently reliable in the measurement of all parameters tested, with the exception of specific gravity.

Animals↗
PubMed2005

Simplified and quantitative saliva buffer capacity test using a hand-held pH meter.

PURPOSE: To evaluate and compare saliva buffer capacity using a hand-held pH meter and a commercial buffer strip in patients at risk of caries. METHODS: To obtain stimulated saliva, 109 patients were given a paraffin wax to chew for 5 minutes. After reading the pH value of 0.5 ml of tested saliva using a portable hand-held pH meter (B-212), 10 microl of 0.1N HCl was titrated into the obtained saliva up to a total titration of 160 microl, and then the pH value read each time. The commercial buffer strip (CRT) was also evaluated. The correlation in ranking results (high, medium, low) between the B-212 pH meter and CRT buffer were statistically analyzed by the Bartlett's test (P < 0.001). RESULTS: At the point of 50 microd of titrated HCl, the individual saliva buffer capacities were ranked into one of the following three categories; high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). The percentages of the tested patients for the different ranks (high, medium, low) of buffer capacity were 50%, 17% and 33% respectively for the B-212 pH meter, and 56%, 17% and 27% respectively for the CRT. For the CRT buffer, 23 out of 109 cases showed inconclusive color change under the colorimetric test. There was significant correlation between ranking buffer capacity measured by the B-212 pH meter and the CRT buffer (P < 0.001).

Adult↗
PubMed1998

Quality assessment of two lactate test strip methods suitable for obstetric use.

Accuracy of lactate determinations in cord blood was tested for one reflectometric (Accusport) and one amperometric (Lactate Pro) microvolume test strip lactate meter. Both meters, using a whole blood sample, measure lower levels of lactate than a reflectometric device considered as a reference method, which analyses lactate in plasma. Readings were unaffected irrespective of lactate concentrations for the Lactate Pro, whilst the Accusport overestimated low lactate concentrations and underestimated high values. Both lactate meters underestimated lactate concentrations at high hematocrits, as compared with the reference method. The Lactate Pro has a fixed sample volume of 5 microliters while the Accusport uses random blood drop as sample volume. However, in analyses with less than 20 microliters sample volume considerable underestimation was found with the Accusport. Coefficient of variation was 3.8-8.9% for the Accusport and 3.1-4.0% for the Lactate Pro within lactate concentrations between 2.1 and 5.3 mmol/l. The amperometric device, the Lactate Pro, performed best in these tests dealing with fetal blood lactate concentrations. The new technique can be a useful tool in perinatal research as well as in obstetric practice.

False Negative Reactions↗
PubMed1995

Influence of toothbrushing, eating and smoking on Dentocult SM Strip mutans test scores.

The Dentocult SM Strip mutans test (D-SM, Vivadent) is a popular method for estimating salivary mutans streptococci and is clinically used for the detection of potential caries risk patients. The influence of toothbrushing, eating and smoking on the reliability of D-SM test scores was assessed in 30 subjects aged 21-39 years. All experiments were performed 24 h after professional tooth cleaning in the morning of 3 consecutive days. On day 1 immediately before and 30 min after toothbrushing, D-SM tests were taken and total salivary colony-forming units per ml were determined. Following the same protocol, the influence of a standardized breakfast and of smoking was evaluated on day 2 and on day 3 respectively. Although all parameters significantly decreased the salivary colony-forming units per ml, only the standardized breakfast induced significant changes in the D-SM test results. Eating therefore should be avoided prior to the performance of the D-SM test.

Adult↗
PubMed2001

Malaria rapid diagnostic devices: performance characteristics of the ParaSight F device determined in a multisite field study.

Microscopic detection of parasites has been the reference standard for malaria diagnosis for decades. However, difficulty in maintaining required technical skills and infrastructure has spurred the development of several nonmicroscopic malaria rapid diagnostic devices based on the detection of malaria parasite antigen in whole blood. The ParaSight F test is one such device. It detects the presence of Plasmodium falciparum-specific histidine-rich protein 2 by using an antigen-capture immunochromatographic strip format. The present study was conducted at outpatient malaria clinics in Iquitos, Peru, and Maesod, Thailand. Duplicate, blinded, expert microscopy was employed as the reference standard for evaluating device performance. Of 2,988 eligible patients, microscopy showed that 547 (18%) had P. falciparum, 658 (22%) had P. vivax, 2 (0.07%) had P. malariae, and 1,750 (59%) were negative for Plasmodium. Mixed infections (P. falciparum and P. vivax) were identified in 31 patients (1%). The overall sensitivity of ParaSight F for P. falciparum was 95%. When stratified by magnitude of parasitemia (no. of asexual parasites per microliter of whole blood), sensitivities were 83% (>0 to 500 parasites/microl), 87% (501 to 1,000/microl), 98% (1,001 to 5,000/microl), and 98% (>5,000/microl). Device specificity was 86%.

Animals↗
PubMed1995

A study into the prevention of fissure caries using an antimicrobial varnish.

The aim of this study, performed in Bangkok, was to evaluate the possibility of reducing fissure caries development using an antimicrobial varnish, Cervitec. Children aged 7-8 years and 12-13 years, 251 in each age group, with at least 2 sound contra-lateral permanent molars, were selected. A split mouth method was used with one test and one control tooth within the same jaw. At baseline and after two years all children were investigated for DMFS and DMFT. In addition, the size of any cavities was estimated. From 200 children, plaque samples of test and control occlusal surfaces were collected at baseline and after one year and processed to estimate the number of mutans streptococci. Mutans streptococci in saliva were estimated by the Strip mutans method. Cervitec varnish, containing 1 per cent chlorhexidine and thymol was applied at baseline, after 3-4 and after 8-9 months. The results showed that: Cervitec varnish reduced fissure caries development significantly; the levels of salivary mutans streptococci at baseline were significantly correlated with caries status at baseline and with total caries increment over the two-year period; caries development in a fissure was significantly correlated to the level of plaque mutans streptococci at that same site; three months after the last varnish application, a certain reduction of mutans streptococci in plaque could be seen in the test teeth; comparing the size of the lesions, more large cavities were found in the untreated teeth. It is concluded that varnishes should be considered as further options for prevention of fissure caries, possibly in more individualised programmes or in combination with already established methods.

Adolescent↗
PubMed2003

Determination of atrazine and carbaryl pesticide residues in vegetable samples using a multianalyte dipstick immunoassay format.

A dipstick assay for the simultaneous determination of atrazine and carbaryl in vegetable samples was developed. The analytical method involved a fast extraction procedure followed by a multi-strip membrane test. The assay took 10 min, with a detection limit (naked eye) of 10 and 200 micro g l(-1) for atrazine and carbaryl, respectively. The cross-reactivities to related compounds tested were negligible except for propazine. Quantification of the pesticides was carried out by measuring the dot colour with a spectrophotometer. IC(50) values (inhibition constant at 50% of the maximum binding) of 2.04 microg l(-1) for atrazine and 92.8 microg l(-1) for carbaryl were achieved by this approach. Vegetable samples were extracted with MeOH. The proposed methodology was used to analyse atrazine and carbaryl and check for compliance with European Union maximum residue levels for vegetables. Recoveries (75-105%) were in agreement with those obtained by GC/MS or HPLC. Standard curves using 25% methanol/75% TBS were used for food sample assays using a multi-analyte dipstick. IC(50) values were 9.2 microg kg(-1) for atrazine and 179.2 microg kg(-1) for cabaryl.

Atrazine↗
PubMed1984

Evaluation of a rapid method to exclude the presence of certain enteric pathogens in stool specimens.

A new commercial method intended to exclude the presence of Salmonella spp., Shigella spp., and Yersinia enterocolitica and to presumptively identify Salmonella isolates within 2 h after primary isolation from stool specimens was evaluated. This system is marketed in Europe as API Z and in the United States as Rapid SST. The strip consists of five pairs of cupules for the screening of five lactose-negative colonies. The first cupule of each pair detects the presence of five enzymatic activities, whereas the second serves to maintain the strain for additional testing if necessary. A total of 197 fresh isolates from stool specimens and 217 stock cultures of Salmonella spp., Shigella spp., and Yersinia enterocolitica were tested, with the API 20E system as a reference method. In the stool specimens, 77.3% of the bacteria could be excluded from further workup for the presence of these organisms within 2 h. Over 97% of the stock strains and each of three fresh Salmonella isolates tested produced a reaction pattern corresponding to a correct presumptive identification. This reaction pattern was not produced by any isolate other than the Salmonella isolates. The API Z system can be used as a screen for the presence of Salmonella and Shigella spp. and can provide an accurate presumptive identification of Salmonella isolates within 2 h after primary isolation.

Bacteria↗
PubMed1998

The use of semi-quantitative urine test-strip (Micral Test) for microalbuminuria screening in patients with diabetes mellitus.

BACKGROUND: Microalbuminuria is an early marker of prognostic significance in diabetic renal disease. However, testing for microalbuminuria in a timed sample of urine using the double antibody radioimmunoassay (RIA) method is cumbersome and requires special laboratory facilities. Recently, a test strip for microalbuminuria, the Micral Test was available and we evaluated the performance of this test strip as a screening method for detection of microalbuminuria. METHODS: One hundred consecutive diabetic patients who were tested to be dipstick-negative (Albustix) for proteinuria were enrolled for the study. Micral Tests were performed on a paired first morning and random urine specimen from the same patient and the results compared with a timed 24-hour urine measurement of urine albumin excretion using the RIA method. RESULTS: Eighteen specimens were tested positive by the RIA method with a urinary albumin range of 32-177 mg/24 hours. With the Micral Test, the following sensitivity, specificity, positive and negative predictive values were obtained: 66.7%. 97.6%, 85.7% and 93.0% for the first morning urine specimens, and 77.8%, 91.5%, 66.7% and 94.9% for the random urine specimens. CONCLUSIONS: These results suggest that Micral Test with either the first morning or random urine specimen offers a simple, reliable, rapid and convenient method for screening of microalbuminuria in the diabetic patient.

Adult↗
PubMed1988

Universal immuno-stick test for direct rapid identification of microbial antigens within 5 minutes. Preliminary report.

Based on experiences with ELISA and biochemical fluorescence assays we have developed a new serologic identification system for detecting all conceivable particle and soluble antigens within 5 min using a very simple, sensitive procedure. This assay represents a sandwich ELISA that has been modified with regard to the sorbent, the enzyme substrate and the identification step. The test is performed as follows: 10 microliter aliquots of antigen dilution, specific or control antibody, respectively, and a phosphatase-conjugated anti-antibody are consecutively mixed. A small strip of special indicator sorbent paper (test stick) is moistened with this mixture for one minute. Subsequently it is dipped 3-5 times alternately in 0.1 M NaOH and a solution of the enzyme-substrate 4-methylumbelliferyl phosphate and immediately evaluated under a UV lamp. Positive samples instantaneously show brilliant light blue fluorescence and decolorization from dark red to white. Although the principle behind the reaction is not yet fully understood, the test works specifically and sensitively within a pg range. Thus far, for example, we have been able to identify Salmonella from suspended milk powder and streptococci from milk (3-5 cells/ml) without previous incubation, enterotoxins from staphylococcal colonies, Aflatoxin M1 and organ-phosphates. Results from examinations of staphylococcal enterotoxins are presented in more detail. Moreover, using a defined antigen, antibodies from different sera could be identified in the same rapid, sensitive and specific manner. Thus, we are convinced that the usual time-consuming enrichment methods for isolating pathogenic bacteria and other immunogenic substances as also current serologic assays will turn out to be superfluous.

Antigens, Bacterial↗