Notes about determining the cut-off value in enzyme linked immunosorbent assay (ELISA)

Barajas-Rojas, José Alfonso; Riemann, Hans; Franti, Charles E.

doi:10.1016/0167-5877(93)90116-b

Cited by 31 publications

(19 citation statements)

References 3 publications

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“…16 This was the mean difference between LSA wells minus medium alone wells plus 2 SD. 22 Stimulation with PHA was used as a positive control. PHA proliferation values between 1.12 and 1.55 optical densities (95% confidence interval) for the mean difference between PHA and medium alone were considered positive.…”

mentioning

confidence: 99%

Leishmania Infection: Laboratory Diagnosing in the Absence of a “Gold Standard”

Rodríguez-Cortés¹,

González-Ojeda²,

Francino³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

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mentioning

confidence: 99%

Leishmania Infection: Laboratory Diagnosing in the Absence of a “Gold Standard”

Rodríguez-Cortés¹,

González-Ojeda²,

Francino³

et al. 2010

The American Journal of Tropical Medicine and Hygiene

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“…14 Thus, serology has been proposed as a monitoring tool, indicating exposure to Salmonella during production, while bacteriological testing is a way to confirm and locate a current infection. 15 To implement a surveillance program, the cutoff point of the ELISA must be continually assessed and adapted to the test purposes, allowing adjustments in sensitivity and specificity, 4 and it should also be adapted according to the development of the Salmonella control program in which it is used.…”

Section: Discussionmentioning

confidence: 99%

“…7 This serovar shares at least 2 LPS antigens with other highly prevalent serovars isolated in this region (Salmonella Agona, Salmonella Derby, Salmonella Bredeney, and Salmonella Panama). The aim of this study was to develop an in-house ELISA test based on the LPS of S. Typhimurium (O: 1,4,5,12) and to evaluate the new test in infected herds in southern Brazil.…”

Section: Introductionmentioning

confidence: 99%

Development and Application of an Enzyme-Linked Immunosorbent Assay to Detect Antibodies against Prevalent Salmonella Serovars in Swine in Southern Brazil

et al. 2007

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Abstract. The implementation of Salmonella control programs in the pork production chain demands rapid and cost-effective methods to assess the prevalence of infection in pig herds. The objective of the present study was to develop an in-house enzyme-linked immunosorbent assay (ELISA) based on S. Typhimurium lipopolysaccharides (LPS) to measure the prevalence of infection caused by Salmonella in swine herds. Coating antigen was produced by phenol extraction of S. Typhimurium culture. After standardization of ELISA test conditions, the assay was validated by testing serum samples on different animal categories: pigs orally inoculated with S. Typhimurium and sentinel animals in contact with them, naturally infected animals, colostrum-deprived piglets, and bacterin-immunized pigs. Seroconversion was observed in inoculated pigs (7 days postinfection [DPI]) and in the sentinels (21 DPI). Nonspecific reactions were not detected in the sera of colostrum-deprived animals. Serum samples from animals immunized with Salmonella Agona, Salmonella Derby, Salmonella Panama, and Salmonella Bredeney bacterins showed marked cross-reaction with the LPS from the serovar Typhimurium. Moreover, positive results obtained with the in-house ELISA were associated with Salmonella isolation in 75 infected pig herds. Comparisons with 2 commercial kits showed a linear correlation coefficient of 0.847 between the in-house ELISA and kit A and 0.922 with kit B but a low agreement in the qualitative results. In conclusion, the newly developed in-house ELISA based on S. Typhimurium LPS can be a useful tool to determine the intensity of Salmonella sp. infection in swine herds.

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“…The iELISA cutoff point was determined by assessing the range between positive and negative samples. Other more empirical methods have been used to set positive-negative cutoff values (2,6,9). Conventional statistical methods for cutoff determination are not applicable given the relatively small number of positive samples available for assay analysis.…”

Section: Discussionmentioning

confidence: 99%

Indirect Enzyme-Linked Immunosorbent Assay for Detection ofBrucella melitensis-Specific Antibodies in Goat Milk

Funk¹,

Tabatabai

Elzer

et al. 2005

J Clin Microbiol

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Brucella melitensis is the cause of brucellosis in sheep and goats, which often results in abortion. Few cases of B. melitensis infection in goats have occurred in the United States over the last 25 years. However, vigilance must be maintained, as it is for the bovine milk industry, to ensure that brucellosis is not introduced into the U.S. goat population. The objective of this study was to develop a sensitive and specific indirect enzyme-linked immunosorbent assay (iELISA) for the detection of B. melitensis-specific antibodies in goat milk. Brucella salt-extractable protein extract was employed as an antigen, and a horseradish peroxidase-labeled polyclonal anti-goat antibody was used as an anti-species conjugate. Thirteen of 13 (100%) individual infected goat milk samples tested positive and 134 of 134 (100%) uninfected bulk milk samples tested negative by the developed iELISA. Three positive milk samples with high, medium, and low absorbance values were used to simulate one positive animal in an otherwise negative herd. By this estimation, one high-titer animal could be detected in a herd of >1,600 animals. Detection estimates for medium-and low-titer animals were one positive animal per herd of <200 and 50 animals, respectively. Based on this estimation, it is recommended that herds be sampled in groups of 50 animals or less for bulk milk testing. The iELISA developed for this study was found to be sensitive and specific and shows potential for use as a bulk milk test for the detection of B. melitensis-specific antibodies in goat milk.Brucella species have impacted human and animal health for thousands of years (4, 18). Brucellae cause disease in goats, cattle, sheep, pigs, dogs, marine mammals, and several wild animals. The focus of this work was to develop a sensitive and specific diagnostic test for the detection of anti-brucella antibodies in goat milk. Goats are the natural hosts for Brucella melitensis. Although the United States has reported the eradication of B. melitensis in animals since 1972 (5), sporadic outbreaks have occurred in relation to infected imported goats (10,23). For the health of American goat milk consumers, vigilance in brucella detection must continue for the goat milk industry just as it has for the bovine milk industry.Brucella detection assays for goats are nearly the same as those for cattle because of the considerable genetic similarity between B. melitensis and B. abortus, and they have been extensively reviewed elsewhere (14). All of these methods have primarily focused on the use of serum as a diagnostic specimen. To date, little has been done to develop and validate diagnostic tests to detect B. melitensis infections by using goat milk. The detection of B. abortus in cow milk has been successful for years by use of the milk ring test (19). Because of a difference between the physiologic properties of goat and cow milk, the milk ring test does not perform well with goat samples (13).The objective of this study was to develop an indirect enzyme-linked immunosorbent assay (i...

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Notes about determining the cut-off value in enzyme linked immunosorbent assay (ELISA)

Cited by 31 publications

References 3 publications

Leishmania Infection: Laboratory Diagnosing in the Absence of a “Gold Standard”

Leishmania Infection: Laboratory Diagnosing in the Absence of a “Gold Standard”

Development and Application of an Enzyme-Linked Immunosorbent Assay to Detect Antibodies against Prevalent Salmonella Serovars in Swine in Southern Brazil

Indirect Enzyme-Linked Immunosorbent Assay for Detection ofBrucella melitensis-Specific Antibodies in Goat Milk

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