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PubMed1994

ELISAs based on recombinant antigens for seroepidemiological studies on Toxoplasma gondii infections in cats.

Two recombinant Toxoplasma gondii polypeptides, H4 and H11, were tested as diagnostic antigens in enzyme-linked immunosorbent assays (ELISAs). The results obtained by ELISAs based on single H4 (H4-ELISA), on single H11 (H11-ELISA) and on a mixture of H4 and H11 (H4/H11-ELISA) were compared with results obtained by an ELISA based on traditional ELISA antigen (TEA-ELISA), an indirect fluorescent antibody test (IFAT), the Sabin-Feldman dye test (SFDT) and a direct agglutination test (DAT). A total of 306 cats from a suburban cat population were tested of which about 45% showed serological evidence of T. gondii infection. Infection rates varied from about 32% for cats kept indoors to about 55% for stray cats. Specificities > 99% were observed for all ELISAs based on the recombinant antigens (H4-ELISA, H11-ELISA and H4/H11-ELISA). The H4/H11-ELISA also reached a sensitivity of 95% which compared very favourably with those observed for the TEA-ELISA (98%) and for the IFAT (94%). Negative and positive predictive values for the H4/H11-ELISA were 96 and > 99%, respectively. Antibody titres measured by the H4/H11-ELISA also correlated well with those measured by the SFDT and the DAT. Hence, the H4/H11-ELISA appears to be a very suitable test for sero-epidemiological studies on T. gondii infections in cats.

Age Factors↗
PubMed2004

Evaluation of an indirect serum ELISA and a bacteriological faecal culture test for diagnosis of Salmonella serotype Dublin in cattle using latent class models.

AIMS: To evaluate a conventional bacteriological test based on faecal culture and an indirect serum ELISA for detection of S. Dublin infected cattle. To compare the predictive values of the two tests in relation to the prevalence. METHODS AND RESULTS: A total of 4531 paired samples from cattle in 29 dairy herds were analysed for presence of S. Dublin bacteria in faeces and immunoglobulins directed against S. Dublin lipopolysaccharide in an indirect serum ELISA. Sensitivity and specificity were estimated at two ELISA cut-off values using a validation method based on latent class models, which presumably provides less biased results than traditional validation methods. Stratification of data into three age groups gave significantly better estimates of test performance of the ELISA. Receiver operating characteristic (ROC) curves were constructed for comparison of overall performance of the ELISA between the three age groups. The sensitivity of the faecal culture test was low (6-14%). ELISA appeared to have a higher validity for animals aged 100-299 days of age than older or younger animals. Overall, the negative predictive value of the ELISA was 2-10 times higher than for the faecal culture test at realistic prevalence of infection in the test population. CONCLUSIONS: The diagnostic sensitivity of the faecal culture test for detection of S. Dublin is poor, the specificity is 1. The superior sensitivity and negative predictive value of the serum ELISA makes this test preferable to faecal culture as an initial screening test and for certification of herds not infected with S. Dublin. SIGNIFICANCE AND IMPACT OF THE STUDY: A quantitative estimate of the sensitivity of a faecal culture test for S. Dublin in a general population was provided. ELISA was shown to be an appropriate alternative diagnostic test. Preferably, samples from animals aged 100-299 days of age should be used as these give the best overall performance of the ELISA. Plots of ROC curves and predictive values in relation to prevalence facilitates optimisation of the ELISA cut-off value.

Animals↗
PubMedDate not supplied

Standardisation and comparison of serial dilution and single dilution enzyme linked immunosorbent assay (ELISA) using different antigenic preparations of the Babesia (Theileria) equi parasite.

Serial dilution and single dilution enzyme linked immunosorbent assays (ELISA) were standardised and their sensitivity and specificity were compared for serodiagnosis of Babesia equi infection. The antibody titres of 24 donkey sera of known identity were determined separately by serial dilution ELISA using three different B. equi antigens namely whole merozoite (WM), cell membrane (CM) and high speed supernatant (HSS). The ratios of the optical density (OD) of known positive and known negative sera at different serum dilutions were calculated and termed as the positive/negative (P/N) ratio. The coefficients of correlation (r) were calculated between the P/N ratios at different dilutions of sera and the log10 antibody titres of the same sera were ascertained by serial dilution ELISA. The highest value of 'r' was obtained at a serum dilution of 1:200. From log10 antibody titre of sera (y) and their P/N ratio at a dilution of 1:200 (x), regression equations (y = a + bx) were calculated separately for the three antigens. Test sera were diluted to 1:200, their OD were read in duplicate wells and were converted to the P/N ratio. Antibody titres were predicted from the P/N ratio using a regression equation separately for the three antigens. Titres obtained by both ELISAs were not significantly different from each other, thus confirming that single dilution ELISA could be successfully used to replace conventional serial dilution ELISA. The sensitivity, specificity and predictive value of single dilution ELISA was validated statistically using 42 B. equi disease-positive sera and 106 B. equi disease-negative sera. The WM antigen was found to be the most sensitive with a higher predictive value for negative test sera as compared to the CM or HSS antigens. Sera positive for other equine infections including Babesia caballi showed no cross-reaction with the three B. equi antigens in ELISA, thus the test was immunologically specific. Antibody titres of 109 unknown field donkey/horse sera obtained by serial and single dilution ELISA using the WM antigen did not show any significant difference. Since the single dilution ELISA was found to be more economical, convenient, sensitive, specific than the serial dilution ELISA and has a high predictive value, it is suitable for use in sero-epidemiological studies on B. equi infections in the field.

Animals↗
PubMed2001

A sensitive in situ ELISA for quantitative measurements of cytokines and antibodies secreted by culture lymphocytes.

Cytokines are usually measured using ELISA and ELISPOT. We have developed an in situ ELISA by combining the advantages of the highly sensitive ELISPOT and the quantitative conventional ELISA techniques to measure cytokines and antibodies secreted by culture lymphocytes. In this assay, lymphocytes were cultured on ELISA plates pre-coated with either a special antigen or mAbs against IL-4, IFN-gamma. The caprtured lymphokines or immunoglobulins were subsequently measured by conventional ELISA procedures. As a comparison, a conventional ELISA was carried out in parallel. The in situ ELISA measured a 5-fold increase in antigen-stimulated IL-4 and IFN-gamma, compared to the conventional ELISA. It also rquired 10,000 times fewer lymphocytes to produce a detectable level of antigen-specific antibodies than the conventional ELISA. We conclude that the in situ ELISA is much more sensitive than a conventional ELISA and less costly and easier to perform than ELISPOT, providing a useful tool to quantitatively measure cell-secreted molecules.

Animals↗
PubMed2003

Evaluation of capture ELISA for detection of antineutrophil cytoplasmic antibodies directed against proteinase 3 in Wegener's granulomatosis: first results from a multicentre study.

OBJECTIVE: To evaluate the performance characteristics of direct and capture ELISA for the detection of PR3-ANCA in Wegener's granulomatosis (WG) in international ANCA reference laboratories. METHODS: Serum samples were derived from patients with histological and clinical diagnosis of WG (n = 60), rheumatoid arthritis (RA) (n = 30) and healthy controls (n = 30). Each of them was tested for the presence of ANCA by indirect immunofluorescence technique (IFT), direct and capture ELISA in six international reference laboratories (Massachusetts General Hospital, Boston; Wieslab AB, Lund; University of Maastricht; University Hospital Groningen; Mayo Clinic, Rochester; Rheumaklinik Bad Bramstedt/University of Schleswig-Holstein Campus Lübeck). Each centre tested the sera according to their house protocols of IFT and ELISA. The diagnostic performance of each test was estimated by receiver operating characteristic curve analysis and sensitivity and specificity in detection of ANCA/PR3-ANCA were calculated for the respective methods. RESULTS: In patients histologically and clinically known as WG, the detection of ANCA by IFT varied between 52 and 83% among the participating centres. PR3-ANCA positivity with the different ELISAs ranged from 53 to 80% in direct ELISA and from 72 to 76% in capture ELISA. While most capture ELISAs successfully detected PR3-ANCA, there were significant differences between IFT and direct ELISA results between laboratories. ROC curve analysis demonstrated that in five of six laboratories the overall diagnostic performance of capture ELISA was superior to IFT and direct ELISA, respectively. CONCLUSION: Capture ELISA is a highly sensitive assay for detection of PR3-ANCA in WG and should be used in conjunction with compatible clinical picture and histological evidence.

Adolescent↗
PubMed1993

Intrathecal antibody synthesis in Lyme neuroborreliosis: use of recombinant p41 and a 14-kDa flagellin fragment in ELISA.

The intrathecal synthesis of IgM and IgG antibodies to Borrelia burgdorferi sonicate, to recombinant flagellin (41 kDa) and to a tryptic peptide of the flagellin (14-kDa fragment) was determined by ELISA in paired cerebrospinal fluid (CSF) and serum samples from 35 patients with Lyme neuroborreliosis (LNB) and in 10 patients with neurosyphilis. The antibody index (AI = QBb/QIg) was calculated from the ratio between CSF/serum quotients for specific antibodies (QBb) and total immunoglobulins (QIg). For the examination of IgG antibodies, the sonicate ELISA was performed with and without pre-absorption with Treponema phagedenis. Of 35 patients with LNB, 31 had intrathecal IgG response to B. burgdorferi demonstrated by sonicate ELISA (24 after absorption of cross-reactive antibodies), 29 had a response demonstrated by flagellin ELISA and 21 of 35 by 14-kDa ELISA. In patients with neurosyphilis the AI (IgG) was elevated in the sonicate ELISA in 7 of 10 samples (none of 10 after absorption of cross-reactive antibodies), in the flagellin ELISA in 5 of 10 samples and in the 14-kDa ELISA in none of 10 samples. Intrathecal synthesis of IgM antibodies to B. burgdorferi was demonstrated in patients with neuroborreliosis by sonicate ELISA in 20 of 35 samples, by flagellin ELISA in 16 of 35 samples and by 14-kDa ELISA in 9 of 35 samples. No intrathecal synthesis of B. burgdorferi-specific IgM could be detected by any assay in patients with neurosyphilis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

ELISA for early diagnosis of histoplasmosis.

An ELISA was developed and evaluated as a method for detecting antibodies against glycosylated and deglycosylated histoplasmin (HMIN). Sera from patients with histoplasmosis, paracoccidioidomycosis, sporotrichosis, coccidioidomycosis, aspergillosis, cryptococcosis and healthy donors were tested by ELISA against purified, deglycosylated histoplasmin (ptHMIN) and compared with purified, native (i.e. glycosylated) histoplasmin (pHMIN). Although cross-reactivity was not abolished when ptHMIN was used in the test, it was reduced (pHMIN ELISA 93 % versus ptHMIN ELISA 96 %). However, there were statistically significant differences between the sensitivities of these two methods for the detection of antibodies (pHMIN ELISA 57 % versus ptHMIN ELISA 92 %; P < 0.001) and between the efficiency of the methods (pHMIN ELISA 83 % versus ptHMIN ELISA 95 %; P < 0.001). These parameters compare better than previously published data relating to the use of treated HMIN in diagnostic ELISAs. Some of the reactivities of serum samples were compared by immunoblotting using deglycosylated HMIN and by immunodiffusion using the crude antigen. The results demonstrated that cross-reactions with heterologous sera in both ELISAs could also be observed in immunoblotting and arose from shared protein epitopes. These data suggest that ELISA using deglycosylated HMIN is a very sensitive diagnostic method and, by using commercially available antigen, it can be easily standardized and performed faster than previous Western blot-based tests using the same antigen. It provides a useful adjunct to existing methods of diagnosis that could be applied even in situations where laboratory facilities were relatively limited.

Antibodies, Fungal↗
PubMed1992

Specificity and sensitivity of first and second generation anti-HCV ELISA in a low prevalence population.

Specificity and sensitivity of the second generation enzyme immunosorbent assay for hepatitis C antibodies were calculated from data on 208,554 blood donors screened with either the first or the second generation tests (ELISA I, ELISA II) or both (4,639 donors). The second generation ELISA was no more specific than the first generation test in this low-prevalence blood donor population (specificity 99.7% vs 99.6%). Most of the donors (93.5%) who were found to be reactive using ELISA II were negative or indeterminate according to a supplemental test, the second generation recombinant immunoblot assay (RIBA II). The second generation ELISA was found to be more sensitive than the first. It identified all 16 donors who were positive according to RIBA II during screening with ELISA I. The latter found only 13 out of 30 donors (43%) who were positive according to RIBA II during screening with ELISA II. If the number of RIBA II positive donors found during the first year of screening with ELISA I (74, 0.024%), and the number of RIBA II positive but ELISA I negative donors found during screening with ELISA II, are taken into consideration it can be estimated that the added sensitivity due to using ELISA II is about 40%.

Blood Donors↗
PubMed2003

[Inter-laboratory evaluation studies of notified ELISA methods for allergic substances (egg)].

Inter-laboratory evaluation studies were conducted for the notified ELISA methods for allergic substances (Egg). Standard extracts of egg spiked in extracts of sausage, sauce, cookie, bread and cereal at a level of 5-20 ng/mL as the sample solution were analyzed in replicate in 10 laboratories. Coefficients of variation (CVs) of all three ELISA methods using an Egg Protein ovalbumin ELISA Kit (ovalbumin kit), an Egg Protein ovomucoid ELISA Kit (ovomucoid kit) and a FASTKIT Egg ELISA kit (Egg ELISA kit) were mostly less than 10%. Mean recoveries of the standard extract of egg were over 40% in the three ELISA methods. Repeatability relative standard deviations of egg standard solution in five food extracts were in the ranges of 18.7-25.5%, 18.6-41.8%, 21.3-43.3% for the ovalbumin kit, the ovomucoid kit and the Egg ELISA kit, respectively. Reproducibility relative standard deviations of egg standard solution in five food extracts were 16.8-35.1%, 19.6-35.8%, 24.7-51.1% for the ovalbumin kit, the ovomucoid kit and the Egg ELISA kit, respectively. The detection limits of all the ELISA methods were 4-5 ng/mL in sample solutions. These results suggested that the notified ELISA methods are reliable and reproducible for the inspection of egg protein levels in extracts of sausage, sauce, cookie, bread and cereal.

Allergens↗
PubMed2004

[Inter-laboratory evaluation studies for development of notified ELISA methods for allergic substances (wheat)].

Extracts of sausage, sauce, pasta sauce, fish paste and cereal spiked with wheat standard protein at a level of 5-20 ng/mL as sample solutions were analyzed in replicate in 10 laboratories. Coefficients of variation (CVs) of both ELISA methods using a Wheat Protein ELISA Kit (Gliadin kit) and a FASTKIT Wheat ELISA Kit (Wheat ELISA kit) were mostly below 10%. Mean recoveries of the wheat standard protein from the food extracts were over 40% in the two ELISA methods except those from cereal extract determined using the Wheat ELISA kit. Repeatability relative standard deviations of wheat standard protein in the five food extracts were in the ranges of 16-26.9% and 3.7-36.2% for the Gliadin kit and the Wheat ELISA kit, respectively. Reproducibility relative standard deviations of wheat standard protein in the five food extracts were 21.6-38.5%, 29.7-53.8% for the Gliadin kit and the Wheat ELISA kit, respectively. The recoveries of wheat standard protein from the cereal extract were improved by the increasing the amount of antibody coated on the plate in the Wheat ELISA kit. The detection limits of both ELISA methods were 1 ng/mL in sample solutions. These results suggested that the notified ELISA methods are reliable and reproducible for the inspection of wheat protein levels in extracts of sausage, sauce, pasta sauce, fish paste and cereal.

Allergens↗
PubMed2000

New ELISA for quantitation of human urokinase receptor (CD87) in cancer.

The serine protease urokinase-type plasminogen activator (uPA), its inhibitor (PAI-1), and its receptor (uPAR; CD87) facilitate cancer cell invasion and metastasis. Whereas uPA and PAI-1 antigen levels determined in tumor tissue extracts of breast cancer patients correlate with disease recurrence and overall survival, the prognostic relevance of uPAR is still a matter of debate. We established two new sandwich-type enzyme-linked immunosorbent assay (ELISA) formats (HU/IIIF10-ELISA and HU/HD13-ELISA) using the epitope-defined monoclonal antibody (mAb) IIIF10 or the conformation-dependent mAb HD13.1, a polyclonal chicken antibody (HU277), and recombinant soluble uPAR (CHO-suPAR) as the standard. The lower detection limit of the assays was at 0.16 ng/ml, with a linear dose-response up to 5 ng/ml of uPAR antigen. Both ELISA formats showed good reproducibility and recovery. The intra-assay and the inter-assay variation coefficients were respectively 4.3% and 11.7% (HU/IIIF10-ELISA) and 4.0% and 10.7% (HU/HD13-ELISA). The recovery rate of uPAR in cell lysates spiked with CHO-suPAR was above 82% and 88%, respectively. With these new ELISA formats, uPAR antigen content in breast cancer tissue extracts and tumor cell lysates was determined and compared to a commercially available ELISA (ADI-ELISA). By all of the three uPAR ELISA formats CHO-suPAR and uPAR present in lysates of non-malignant epithelial cells and stimulated monocytes were quantified with similar sensitivity. Interestingly, in breast cancer cell lines of epitheloid origin a higher uPAR antigen content was determined by the HU/IIIF10-ELISA than the HU/HD13- or ADI-ELISA formats. In lysates of fibroblastic breast cancer cell lines similar uPAR values were obtained with the HU/IIIF10- and ADI-ELISA formats, whereas with the HU/HD13-ELISA significantly lower uPAR concentrations were determined. The prognostic relevance of tumor uPAR antigen was evaluated in 199 primary breast cancer patients with a median follow-up of 24 months. uPAR antigen values above the cut-off of 3.33 ng/mg protein as determined by the HU/IIIF10-ELISA were significantly correlated with short disease-free survival (p=0.025). Results obtained by the other two ELISA formats (HU/HD13-ELISA and ADI-ELISA) were not associated with prognosis. Our findings stress the need of well-characterized antibodies, which detect both uPAR of non-malignant and tumor cells, in setting up a uPAR-ELISA useful for assessing breast cancer patient prognosis.

Animals↗
PubMed2006

Anti-dsDNA antibody testing by Farr and ELISA techniques is not equivalent.

OBJECTIVE: To determine the degree of correlation between Farr and ELISA methods of detecting anti-dsDNA antibodies in patients with systemic lupus erythematosus (SLE), and their association with measures of disease activity. METHODS: Anti-dsDNA antibodies were assayed using the Farr and ELISA methods in patients followed between January 1, 2000, and December 31, 2002. Statistical correlations between Farr and ELISA were determined. Relationships between the 2 assays and measures of disease activity [SLE Disease Activity Index 2000 (SLEDAI-2K-DNA), renal, central nervous system (CNS), and vasculitis] were determined for the same clinic visit. RESULTS: 550 patients with 2940 clinic visits met the inclusion criteria. Correlation between Farr and ELISA levels was 0.46 using the first visit for each patient. When the Farr was abnormal, the ELISA was equally likely to be normal or abnormal. Abnormal Farr results were associated with higher SLEDAI-2K scores than normal Farr results (6.2 vs 4.3, respectively; p < 0.0001). There was less of a distinction with ELISA results (5.9 vs 4.8; p = 0.04). Farr levels were significantly associated with the presence of renal disease and vasculitis, while ELISA levels were not. Neither Farr nor ELISA results correlated with the presence of active CNS involvement. CONCLUSION: Farr and ELISA techniques for the detection of anti-dsDNA antibodies in patients with SLE are poorly correlated. The Farr is superior to the ELISA in correlating with measures of global disease activity, as well as renal and vasculitis involvement. The Farr technique should continue to be used in clinical practice. The ELISA adds no additional information.

Adolescent↗
PubMed2006

[Detection of anti-SSA/Ro antibody by ELISA, double immunodiffusion, and immunoblotting: a comparative study].

OBJECTIVES: To compare the specificity and sensitivity of ELISA, double immunodiffusion (ID), and immunoblotting (IB) in detection of anti-SSA/Ro antibodies in the sera of patients with connective tissue disease (CTD). METHODS: ELISA, double ID, and IB were used to detect the serum levels of anti-SSA/Ro antibodies in 7736 patients undergoing screening of CTD, 122 healthy blood donors, and 166 CTD patients positive in antinuclear antibody (ANA) and/or anti-extractable nuclear antigen (ENA). RESULTS: (1) The sera of the 122 healthy blood donors were all negative in anti-SSA/Ro antibodies by these three methods. (2) 1085 of the 7736 sera undergoing screening of CTD were positive in the anti-SSA/R0 antibody of the relative molecular quantity of 52,000. Ninety-two of the 1085 patient, ANA and/or anti-ENA negative, were all confirmed by ELISA and ID to be negative in anti-SSA/R0 antibodies. And 993 of these 1085 patients were positive in ANA and/or anti-ENA antibody, 917 of which were shown to be anti-SSA/R0 antibodies positive by ELISA (92.3%, 917/993), and 860 of which were shown to be anti-SSA/R0 antibodies positive by ID (86.6%, 860/993). (3) The prevalence rates of anti-SSA/Ro antibodies in the 166 CTD patients detected by ELISA, ID, and IB respectively were 76.5% (127/166), 65.1% (108/166), and 49.4% (82/166) respectively. (4) 127 of the 166 sera of the CTD group were anti-SSA/Ro antibody positive By ELISA, and 108 of the 166 sera were anti-SSA/R0 antibody positive by ID, with a coincidence rate of ELISA and ID of 88.6% (147/166), and there was a significant difference in positive rate of anti-SSA/Ro antibody between these two methods (P < 0.001). 81 of the 166 CTD sera were anti-SSA/Ro antibody positive with a positive rate of 63.8%. The coincidence rate of ID and IB was 75.9% (126/166) and there was a significant difference in positive rate of anti-SSA/Ro antibody between ID and IB methods too (P < 0.001). (5) Spearman's rank correlation study showed that the correlation coefficient between ELISA and ID was 0.828 (P < 0.001). CONCLUSIONS: (1) ELISA and ID are more specific than IB in detection of anti-SSA/Ro antibody. (2) The specificity of IB was lower, however, when ANA and/or other anti-ENA are positive, its specificity would be improved markedly. (3) ELISA is more sensitive than ID, and ID is more sensitive than IB in detection of anti-SSA/Ro antibody. (4) There is a significant positive correlation between ELISA and ID quantitatively.

Antibodies, Antinuclear↗
PubMedDate not supplied

Comparative evaluation of brain CT and ELISA in the diagnosis of neurocysticercosis.

This study compares the results of cysticercus-specific IgG antibody levels, as measured by enzyme-linked immunosorbent assay (ELISA), with brain CT findings in suspected neurocysticercosis and to assess the clinical significance of ELISA. One hundred twenty-three neurologic patients were examined by both brain CT and ELISA. Sensitivity and specificity of ELISA in confirmed cases were 94% and 91%, respectively. Patients with multiple cysts without enhancement on CT, which were thought to represent viable cysticerci, were positive by ELISA. Those with cysts with enhancement or poorly defined low densities or enhancing nodules, which represented cysticerci on degeneration, were also positive by ELISA. Those with multiple spotty calcifications, which represent cysticerci in the inactive stage, were negative by ELISA. Those with mixed CT findings of the above, which represent the various stages of infection in a patient, were positive by ELISA. Those with only enhancing nodules with surrounding edema, which were thought to be other inflammatory granulomas, were negative by ELISA. If patients with only hydrocephalus on CT are positive by ELISA, they can be confidently diagnosed as having ventricular cysticercosis. The results indicate that ELISA is useful as a complementary diagnostic tool, especially in patients with equivocal CT findings of neurocysticercosis. Provision of etiologic information on a biologic basis was the advantage of this serologic test.

Adolescent↗
PubMed1993

Development of indigenous ELISA for rotavirus diagnosis & its comparison with commercial kit.

Preparation of reagents for the diagnosis of rotavirus by enzyme linked immunosorbent assay (ELISA) was carried out at the National Institute of Virology (NIV), Pune. This is a double antibody sandwich ELISA test. The coating antibody was raised in guinea pig against SA-11 (Simian rotavirus), and is used at 1:20,000 dilution. The indicator antibody was also raised against SA-11 in rabbits. The rabbit preimmune serum is used as negative control serum. Both, pre- and post-immune rabbit antisera are used at 1:10,000 dilution in the test. Goat IgG-HRP conjugate against rabbit IgG was procured commercially (Sigma, USA). Results of ELISA test can be read visually. A total of 63 pretested faecal specimens and 38 specimens of rotavirus in different concentrations were compared simultaneously by the NIV ELISA and Dakopatts ELISA. Of the 63 specimens, 36 were positive in NIV ELISA and 33 positive by Dakopatts ELISA. Human and animal rotavirus strains also showed higher titers in NIV ELISA than Dakopatts ELISA. From our data we conclude that NIV ELISA is 100 per cent specific and more sensitive than Dakopatts ELISA test. It is much more economical than any other commercial kit available for the diagnosis of rotavirus. Since the reagents are in lyophilized form, they are suitable for use in developing countries.

Animals↗
PubMed1996

Comparison of the sensitivity & specificity of a polyclonal versus monoclonal capture antibody based Bead ELISA for direct detection of cholera toxin from stool specimens.

This study was conducted to examine whether substitution of polyclonal anti-CT IgG (PAb) coated beads with monoclonal anti-CT IgG, (MAb) coated beads would enhance the sensitivity and specificity of the Bead ELISA for direct detection of CT in stool samples of cholera patients. Sensitivity of MAb Bead ELISA was found to be more efficient (92.7%) than the PAb Bead ELISA (88.2%) in comparison to the 'gold standard' method of conventional culture method (CM). However, the MAb based Bead ELISA had lower specificity (45%) than that of PAb Bead ELISA (51.8%). Further, the positive predictive value was also lower in MAb Bead ELISA (69.9%) as compared to PAb Bead ELISA (82.1%). Generally, all the statistical evaluation demonstrated better agreement between PAb (77.9%) and MAb (72.6%) Bead ELISAs in direct detection of free CT and culture method in confirming the causative organism i.e., Vibrio cholerae in stool specimens. When the two assay systems, viz., PAb and MAb Bead ELISAs were compared, the superiority of the PAb Bead ELISA over MAb Bead ELISA was clearly evident as it had 82.4 per cent of agreement value.

Antibodies, Monoclonal↗
PubMed1999

Desmoglein 3-ELISA: a pemphigus vulgaris-specific diagnostic tool.

BACKGROUND: Pemphigus vulgaris (PV) is an autoimmune-blistering disease of the skin and mucous membranes caused by autoantibodies against desmoglein 3 (Dsg3), an epidermal desmosomal adhesion protein of the cadherin family. Cloning of the Dsg3 gene and expression of the protein in a native conformation enabled the recent development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for the detection of PV autoantibodies. OBJECTIVES: To evaluate serum samples from patients with PV and other dermatologic diseases for anti-Dsg3 antibodies. To compare ELISA values with autoantibody titers obtained by classic indirect immunofluorescence (IIF). DESIGN: Serum samples from patients with PV and various other bullous and nonbullous skin diseases were tested for anti-Dsg3 reactivity by ELISA. SETTING: Ambulatory and hospitalized patients from a university hospital. PATIENTS: Fifty-two serum samples from 11 patients with PV, and serum samples from 11 patients with bullous pemphigoid, 12 patients with other bullous diseases, 22 patients with various nonbullous skin disorders, and 10 healthy individuals were tested. RESULTS: Forty-seven (98%) of 48 serum samples from patients with PV that were positive by IIF on monkey esophagus were also reactive by Dsg3-ELISA, whereas 4 of 4 IIF-negative PV serum samples showed no reactivity by ELISA. In addition, negative ELISA results were obtained from 11 of 11 serum samples from patients with bullous pemphigoid, 10 of 12 serum samples from patients with other bullous skin disorders, 7 of 9 serum samples from patients with autoimmune-connective tissue diseases, and 13 of 13 serum samples from patients with other nonbullous skin diseases. Interestingly, 1 patient with paraneoplastic pemphigus had positive ELISA results. There was a positive correlation (r = 0.654) between ELISA values and IIF titers within the whole population with PV. In addition, when multiple serum samples from 1 patient with PV sampled over a 2-year period were tested, ELISA reactivity paralleled both the IIF titers and the clinical course. CONCLUSION: The Dsg3-ELISA is a sensitive, objective, and PV-specific test that should be considered as an adjunct test for the management of patients with PV.

Adult↗
PubMed2002

ELISA test to detect Chlamydophila pneumoniae IgG.

A new ELISA test (Chlamydophila pneumoniae IgG, Vircell, Spain) to detect Chlamydophila pneumoniae IgG was evaluated. The micro-immunofluorescence (MIF) test was used as reference method. Chlamydia trachomatis and Chlamydophila psittaci elementary bodies were also assayed. Two hundred and sixteen sera were included in the study: 66 from patients with peripheral arterial occlusive disease (Panel 1), 68 from adults with pneumonia (Panel 2), 44 from healthy adults (Panel 3) and 38 from patients with a sexuality transmitted disease by C. trachomatis (Panel 4). In Panel 1, 51 sera (77%) had antibody titres between 32 and 128; 4 out of 15 sera with IgG titres < 32 were positive by ELISA test and 2 sera with 32 IgG titres were uncertain by ELISA; the remaining 60 sera were correctly classified, giving a 91% concordance between the techniques. In Panel 2, 55 sera (81%) had IgG titres between 32 and 512; 2 out of 13 sera with IgG titres < 32 were positive by ELISA and 2 sera with 32 titres were uncertain by ELISA; the remaining 64 sera were correctly classified, giving a 97% concordance. In Panel 3, 22 sera (50%) had IgG titres between 32 and 64; only 1 out of 22 sera with IgG titres < 32 was positive by ELISA, giving a 97% concordance between the techniques. In Panel 4, there were 24 (63%) negative, 10 (26%) uncertain and 4 (10%) positive results by ELISA, giving an 86% concordance. The C. pneumoniae ELISA test demonstrated 100% sensitivity and 85% specificity. The IgG ELISA test demonstrated a good concordance with the MIF test without the drawbacks associated with the latter assay. We conclude that the ELISA test could be an alternative to the MIF test.

Antibodies, Bacterial↗