Identification of Streptococcus pyogenes in a Pediatric Outpatient Department: A Practical System Designed for Rapid Results and Resident Teaching

PEDIATRICS ◽  
1974 ◽  
Vol 54 (6) ◽  
pp. 718-723
Author(s):  
Katherine Sprunt ◽  
Dorothea Vail ◽  
Russell S. Asnes
Keyword(s):  
False Positive ◽  
Fluorescent Antibody ◽  
False Negative ◽  
Screening Method ◽  
Rapid Screening ◽  
Resident Teaching ◽  
Antibody Uptake ◽  
Busy Clinic ◽  
Group A ◽  
Laboratory Tool

A rapid screening method for identification of clinic patients with pharyngitis who are carrying group A beta-hemolytic streptococci and for teaching residents the values and limitations of the culture-disk approach to identification has been reviewed as developed for a busy clinic and a busy hospital laboratory. Identification of positive cultures in less than 24 hours, using Taxos A disk and specific fluorescent antibody uptake, resulted in 12% apparent false-positive and 3.6% false-negative reports. However, when viewed in the light of the techniques used for verifying results, there were probably 3% false-positive and 3% false-negative reports. The screening method is considered acceptably reliable and practical as a laboratory tool and a resident teaching device.

Rapid screening method for polymorphism of group A apolipoproteins

1992 ◽  
Vol 6 (5) ◽  
pp. 290-296 ◽  
Author(s):  
Bouchra Harake ◽  
Patrick S. M. Caines ◽  
Roger J. Thibert
Keyword(s):  
Screening Method ◽  
Rapid Screening ◽  
Group A ◽  
Rapid Screening Method

scholarly journals High Diagnostic Accuracy of Antigen Microarray for Sensitive Detection of Hepatitis C Virus Infection

2008 ◽  
Vol 54 (2) ◽  
pp. 424-428 ◽  
Author(s):  
Jung-ah Kwon ◽  
Hyeseon Lee ◽  
Kap N o Lee ◽  
Kwangchun Chae ◽  
Seram Lee ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Detection Limit ◽  
Diagnostic Accuracy ◽  
False Positive ◽  
Sol Gel ◽  
False Negative ◽  
Screening Method ◽  
Confirmatory Test ◽  
Specificity And Sensitivity

Abstract Background: Hepatitis C virus (HCV) can be transmitted through blood transfusion. Screening ELISA, the most widely used method for HCV diagnosis, sometimes yields false-positive and false-negative results, so a confirmatory test is used. This secondary testing is labor-intensive and expensive, and thus is impractical for massive blood bank screening. Therefore, a new massive screening method with high accuracy is needed for sensitive and specific detection of HCV. Methods: With sol-gel material, we designed novel antigen microarray in 96-well plates for HCV detection. Each individual well was spotted with 4 different HCV antigens. We used this new system to test 154 patient serum samples previously tested for HCV by ELISA (87 HCV positive and 67 HCV negative) (HCV EIA3.0, ABBOTT). We assessed the detection limit of our microarray system with the use of serial 10-fold dilutions of an HCV-positive sample. Results: Our microarray assay was reproducible and displayed higher diagnostic accuracy (specificity) (98.78%) than did the ELISA (81.71%). Our method yielded significantly fewer false-positive results than did the ELISA. The detection limit of our assay was 1000 times more sensitive than that of the ELISA. In addition, we found this novel assay technology to be compatible with the currently employed automated methods used for ELISA. Conclusion: We successfully applied the sol-gel–based protein microarray technology to a screening assay for HCV diagnosis with confirmatory test-level accuracy. This new, inexpensive method will improve the specificity and sensitivity of massive sample diagnosis.

Performance criteria for rapid screening methods to detect mycotoxins

2014 ◽  
Vol 7 (4) ◽  
pp. 439-447 ◽  
Author(s):  
C. von Holst ◽  
J. Stroka
Keyword(s):  
False Negative ◽  
Screening Method ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Rapid Screening ◽  
Cost Ratio ◽  
Screening Methods ◽  
Method Performance ◽  
Official Control ◽  
The Impact

The paper describes the validation of screening methods that are used for official control to classify samples into negative and suspect positive samples. The concept is based on the principle that negative samples are considered as compliant, whereas suspect positive samples need to be re-analysed with confirmatory methods. An important performance criterion often used is a maximum value of 5% for the probability of false negative results obtained on samples that contain the analyte at the legal limit. Since the result of analysis is a binary decision, specific validation schemes need to be applied. The paper places emphasis on practical aspects of the calculation of the method performance characteristics, which are required to check whether the methods fulfil the performance criterion. The paper shows that screening methods based on a visual inspection, e.g. a dipstick, require special data treatment. In contrast there are many methods where the classification into negative and suspect positive samples is based on the comparison of a measured response against a cut-off value. This type of methods can be validated with quantitative statistics. The paper also elaborates on the calculation of the rate of false positive results of compliant samples. In addition the impact on the economical aspect of the use of the screening method is estimated, taking into account external factors such as the cost ratio between the screening and the confirmatory method and the occurrence of non-compliant samples in the entire population of the samples.

Current Status of Immunofluorescent Methodology for Salmonellae1

1981 ◽  
Vol 44 (5) ◽  
pp. 381-384 ◽  
Author(s):  
BERENICE M. THOMASON
Keyword(s):  
Fluorescent Antibody ◽  
Screening Method ◽  
Rapid Screening ◽  
Current Status ◽  
Official Method ◽  
Pathogenic Microorganisms ◽  
Advantages And Disadvantages ◽  
Food And Feed ◽  
History Of ◽  
Feed Samples

The fluorescent antibody (FA) method for detecting salmonellae in food and feed samples is now an official method of the Association of Official Analytical Chemists. The need for a rapid screening method for detecting these pathogenic microorganisms in suspect products led to development of the FA method. A brief history of the development of the FA test, its evaluation by various investigators and its use by food laboratories are described in this report. Advantages and disadvantages of the method are discussed with suggestions for improvement of the technique.

COMPARISON OF SALMONELLA POLYVALENT H ANTISERA, DIRECT FLUORESCENT ANTIBODY, AND CULTURE PROCEDURES IN DETECTING SALMONELLAE FROM EXPERIMENTALLY CONTAMINATED GROUND BEEF UNDER FROZEN STORAGE

1974 ◽  
Vol 37 (7) ◽  
pp. 369-371
Author(s):  
W. C. Ladiges ◽  
J. F. Foster ◽  
W. M. Ganz
Keyword(s):  
False Positive ◽  
Fluorescent Antibody ◽  
False Negative ◽  
Frozen Storage ◽  
Ground Beef ◽  
Gram Negative ◽  
Selective Enrichment ◽  
Direct Fluorescent Antibody ◽  
False Position ◽  
Efficient Screening

A direct fluorescent antibody (FA) test and a polyvalent H agglutination (poly H) test with separate gram-negative (GN) and tetrathionate (TT) broth enrichments were compared with culture methodology in detecting salmonellae from experimentally contaminated ground beef. The FA test had the most false-position reactions (28%, but concurrent culture results reduced these to 7%) and the lowest number of false-negative reactions (4%). The poly H test was more efficient when TT broth was used for selective enrichment. On the basis of fewer false-negative reactions and the greater number of false-positive reactions that were culturally confirmed to be salmonellae, the FA test would appear to be a more efficient screening test in detecting salmonellae from artificially contaminated ground beef held at frozen temperatures.

Comparison between VIDAS Automatic Enzyme-Linked Fluorescent Immunoassay and Culture Method for Salmonella Recovery from Pork Carcass Sponge Samples

2002 ◽  
Vol 65 (10) ◽  
pp. 1656-1659 ◽  
Author(s):  
KUANG-SHENG YEH ◽  
CHIN-EN TSAI ◽  
SHIH-PING CHEN ◽  
CHAO-WEI LIAO
Keyword(s):  
False Negative ◽  
Screening Method ◽  
Culture Method ◽  
Automated System ◽  
Rapid Screening ◽  
Assay Method ◽  
Intensive Culture ◽  
Negative Results ◽  
False Negative Results ◽  
Potential Alternative

VIDAS Salmonella (VIDAS-SLM) is an automated system that uses the enzyme-linked fluorescent assay method to detect Salmonella species. This study evaluated the efficacy of the VIDAS-SLM method in detecting Salmonella species in pork carcass sponge samples gathered from 10 slaughter plants in Taiwan. Two hundred fifty-seven pork carcass sponge samples were screened by the VIDAS-SLM method and by the culture method in parallel. While 18 sponge samples were found to test positive by both methods, the VIDAS-SLM method detected four additional positive samples for which the culture method failed to recover Salmonella. The specificity of the VIDAS-SLM method was found to be 0.98, and its sensitivity was 1.0, since no false-negative results occurred. Artificially inoculated Salmonella at concentrations as low as 5.0 × 100 CFU/ml was detected in the heat-inactivated sponge sample in the presence or absence of 5.0 × 104 CFU of Citrobacter freundii per ml. Thus, the VIDAS-SLM method is a rapid screening method and a potential alternative to the time- and labor-intensive culture method.

scholarly journals Rapid Mycobacterial Liquid Culture-Screening Method for Mycobacterium avium Complex Based on Secreted Antigen-Capture Enzyme-Linked Immunosorbent Assay

2009 ◽  
Vol 16 (5) ◽  
pp. 613-620 ◽  
Author(s):  
Sung Jae Shin ◽  
Kelly Anklam ◽  
Elizabeth J. B. Manning ◽  
Michael T. Collins
Keyword(s):  
Immunosorbent Assay ◽  
Mycobacterium Avium ◽  
False Positive ◽  
High Performance ◽  
Liquid Culture ◽  
False Negative ◽  
Screening Method ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Test

ABSTRACT Sensors in automated liquid culture systems for mycobacteria, such as MGIT, BacT/Alert 3D, and Trek ESP II, flag growth of any type of bacteria; a positive signal does not mean that the target mycobacteria are present. All signal-positive cultures thus require additional and often laborious testing. An immunoassay was developed to screen liquid mycobacterial cultures for evidence of Mycobacterium avium complex (MAC). The method, called the MAC-enzyme-linked immunosorbent assay (ELISA), relies on detection of MAC-specific secreted antigens in liquid culture. Secreted MAC antigens were captured by the MAC-ELISA with polyclonal anti- Mycobacterium avium subsp. paratuberculosis chicken immunoglobulin Y (IgY), detected using rabbit anti-MAC IgG, and then revealed using horseradish peroxidase-conjugated goat anti-rabbit IgG. When the MAC-ELISA was evaluated using pure cultures of known mycobacterial (n = 75) and nonmycobacterial (n = 17) organisms, no false-positive or false-negative MAC-ELISA results were found. By receiver operator characteristic (ROC) analysis of 1,275 previously identified clinical isolates, at the assay optimal cutoff the diagnostic sensitivity and specificity of the MAC-ELISA were 92.6% (95% confidence interval [95% CI], 90.3 to 94.5) and 99.9% (95% CI, 99.2 to 100), respectively, with an area under the ROC curve of 0.992. Prospective evaluation of the MAC-ELISA with an additional 652 clinical samples inoculated into MGIT ParaTB medium and signaling positive per the manufacturer's instructions found that the MAC-ELISA was effective in determining those cultures that actually contained MAC species and warranting the resources required to identify the organism by PCR. Of these 652 MGIT-positive cultures, the MAC-ELISA correctly identified 96.8% (of 219 MAC-ELISA-positive cultures) as truly containing MAC mycobacteria, based on PCR or high-performance liquid chromatography (HPLC) as reference tests. Only 6 of 433 MGIT signal-positive cultures (1.4%) were MAC-ELISA false negative, and only 7 of 219 MGIT signal-negative cultures (3.2%) were false positive. The MAC-ELISA is a low-cost, rapid, sensitive, and specific test for MAC in liquid cultures. It could be used in conjunction with or independent of automated culture reading instrumentation. For maximal accuracy and subspecies-specific identification, use of a confirmatory multiplex MAC PCR is recommended.

scholarly journals Real-Time PCR Method for Detection of Salmonella spp. in Environmental Samples

2017 ◽  
Vol 83 (14) ◽  
Author(s):  
Kuppuswamy N. Kasturi ◽  
Tomas Drgon
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
False Negative ◽  
Screening Method ◽  
Reference Method ◽  
Rapid Screening ◽  
Content Type ◽  
Pcr Method ◽  
Group D

ABSTRACT The methods currently used for detecting Salmonella in environmental samples require 2 days to produce results and have limited sensitivity. Here, we describe the development and validation of a real-time PCR Salmonella screening method that produces results in 18 to 24 h. Primers and probes specific to the gene invA, group D, and Salmonella enterica serovar Enteritidis organisms were designed and evaluated for inclusivity and exclusivity using a panel of 329 Salmonella isolates representing 126 serovars and 22 non-Salmonella organisms. The invA- and group D-specific sets identified all the isolates accurately. The PCR method had 100% inclusivity and detected 1 to 2 copies of Salmonella DNA per reaction. Primers specific for Salmonella-differentiating fragment 1 (Sdf-1) in conjunction with the group D set had 100% inclusivity for 32 S. Enteritidis isolates and 100% exclusivity for the 297 non-Enteritidis Salmonella isolates. Single-laboratory validation performed on 1,741 environmental samples demonstrated that the PCR method detected 55% more positives than the Vitek immunodiagnostic assay system (VIDAS) method. The PCR results correlated well with the culture results, and the method did not report any false-negative results. The receiver operating characteristic (ROC) analysis documented excellent agreement between the results from the culture and PCR methods (area under the curve, 0.90; 95% confidence interval of 0.76 to 1.0) confirming the validity of the PCR method. IMPORTANCE This validated PCR method detects 55% more positives for Salmonella in half the time required for the reference method, VIDAS. The validated PCR method will help to strengthen public health efforts through rapid screening of Salmonella spp. in environmental samples.

Comparison of an ELISA-based Screening Test with Liquid Chromatography for the Determination of Aflatoxins in Corn

1991 ◽  
Vol 74 (5) ◽  
pp. 827-829
Author(s):  
Rodney W Beaver ◽  
Mary A James ◽  
Tay Y Lin
Keyword(s):  
Liquid Chromatography ◽  
Immunosorbent Assay ◽  
False Positive ◽  
Screening Test ◽  
False Negative ◽  
Screening Method ◽  
Incorrect Response ◽  
False Positives ◽  
Enzyme Linked Immunosorbent Assay

Abstract An enzyme-linked immunosorbent assay (ELISA) screening test (CITE PROBE) was compared to liquid chromatography (LC) for the determination of aflatoxins in naturally contaminated corn samples. The CITE PROBE, with a positive/negative cutoff of 5 ng/g aflatoxin Bi, was correct (based on LC results) on 47 of 51 samples. Two of the Incorrect responses by the CITE PROBE were false positives on samples containing 4.4 ng/g and 4.1 ng/g aflatoxins by LC. Another incorrect response was a false negative on a sample containing 5.5 ng/g aflatoxins by LC. The fourth Incorrect response was a false positive on a sample containing 1.9 ng/g aflatoxins by LC. On the basis of these results, the CITE PROBE was determined to be a reliable screening method for the detection of % 5 ng/g aflatoxins in corn.

scholarly journals Simultaneous Detection of Antibodies to Mouse Hepatitis Virus Recombinant Structural Proteins by a Microsphere-Based Multiplex Fluorescence Immunoassay

2011 ◽  
Vol 18 (5) ◽  
pp. 758-766 ◽  
Author(s):  
Satoshi Kunita ◽  
Kanako Kato ◽  
Miyuki Ishida ◽  
Kozue Hagiwara ◽  
Shuko Kameda ◽  
...  
Keyword(s):  
False Positive ◽  
Hepatitis Virus ◽  
Fluorescent Antibody ◽  
Laboratory Mouse ◽  
False Negative ◽  
Mouse Hepatitis Virus ◽  
Simultaneous Detection ◽  
False Negative Rate ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples

ABSTRACTWe describe a new microsphere-based multiplex fluorescent immunoassay (MFI) using recombinant mouse hepatitis virus (MHV) proteins to detect antibodies to coronaviruses in mouse and rat sera. All the recombinant proteins, including nucleocapsid (N) and 3 subunits of spike protein, S1, S2, and Smid, showed positive reactivity in MFI with mouse antisera to 4 MHV strains (MHV-S, -A59, -JHM, and -Nu67) and rat antiserum to a strain of sialodacryoadenitis virus (SDAV-681). The MFI was evaluated for its diagnostic power, with panels of mouse sera classified as positive or negative for anti-MHV antibodies by enzyme-linked immunosorbent assay (ELISA) using MHV virion antigen and indirect fluorescent antibody assay. The reactivities of 236 naturally infected mouse sera were examined; 227 samples were positive by MFI using S2 antigen (96% sensitivity), and 208 samples were positive using N antigen (88% sensitivity). Based on the assessment by MFI using the S2 and N antigens, only 3 serum samples showed double-negative results, indicating a false-negative rate of 1.3%. In 126 uninfected mouse sera, including 34 ELISA false-positive sera, only 7 samples showed false-positive results by MFI using either the S2 or N antigen (94% specificity). Similarly, the S2 and N antigen-based MFI was 98% sensitive and 100% specific in detecting anticoronavirus antibodies in rat sera. Thus, this MFI-based serologic assay using the S2 and N antigens promises to be a reliable diagnostic method, representing a highly sensitive and specific alternative to traditional ELISA for detection of coronavirus infections in laboratory mouse and rat colonies.

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