Thin Layer Immunoassay Research Articles

Thin Layer Immunoassay: An Economical Approach to Diagnose Helicobacter pylori Infection in Gastroduodenal Ulcer Disease Patients of Pakistan, a Comparative Analysis.

Helicobacter pylori is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. The majority of H. pylori-associated patients live in underdeveloped areas, facing the problem of lack of proper diagnostic facility. Hence, a simple and economical assay is required to handle the majority of gastric patients. Serum samples from gastroduodenal ulcers and gastritis patients were screened for H. pylori infection by thin layer immunoassay. A polystyrene plate coated with H. pylori sonicate whole cell antigen (10 µg/mL). Two-fold diluted patient's serum was allowed to react at 37 °C, incubated at 60 °C for 1 min over a water bath and the water condensation pattern for the H. pylori antibody was recorded. ELISAs were used as reference assays to evaluate the efficacy of the developed thin layer immunoassay (TLI). Gastric patients' blood samples (62% male and 6% female) tested positive for H. pylori, while age-wise, 15-25-year-old males (36%) and 65-75-year-old females (50%) showed the highest number of H. pylori infections. TLI showed sensitivity (72-67%), specificity (100%), accuracy (94-69%) and κ value (0.493-0.357) in comparison with wELISA (Surface whole cell ELISA), sELISA (sonicate whole cell ELISA) and kELISA (commercial KIT ELISA). We conclude that thin layer immunoassay is a low cost, fast, simple and clinically reliable method for H. pylori diagnosis at initial stages in patients in under-developed countries.

Serological Evaluation of Thin-Layer Immunoassay–Enzyme-Linked Immunosorbent Assay for Antibody Detection in Human Trichinellosis

A new immunoenzymatic test, named the thin-layer immunoassay-enzyme-linked immunosorbent assay (TIA-ELISA), was evaluated for antibody detection in human trichinellosis using excretion and secretion products prepared from Trichinella spiralis muscle larvae. Serum samples from people with positive muscle biopsies or symptoms compatible with the disease (n = 8 or 26, respectively), all reactive in enzyme-linked immunoelectrotransfer blot assay (EITB), as well as 67 serum samples from healthy, EITB-negative people, were tested in an ELISA and TIA-ELISA. TIA-ELISA was performed in polystyrene plastic petri dishes by adding dots of 10 microl each of antigen (7 microg/ml) followed by adding diluted serum and the conjugate. Finally, the substrate mixed with agar was added to develop the reaction. Enzymatic by-products were easily detected by the naked eye as defined dots. Sensitivity and specificity were 76 and 94% for ELISA, and both parameters were 91% for TIA-ELISA. The kappa correlation indices for both tests in relation to EITB were 0.73 and 0.80, respectively. The TIA-ELISA can be carried out with common laboratory equipment in 3 h and uses lower quantities of antigen than EITB and ELISA. Since TIA-ELISA is easy to perform, cheap, sensitive, and specific, the test could be an acceptable alternative to use in clinical laboratories lacking specialized equipment needed for ELISA and EITB and in field studies for antibody detection in human trichinellosis.

Use of a High Molecular Weight <i>Entamoeba histolytica</i> Antigen Fraction in Enzyme-Linked Immunosorbent Assay and Thin Layer Immunoassay Tests

A high molecular weight Entamoeba histolytica antigen fraction I was employed for the determination of anti-amoebic antibodies in ELISA and thin layer immunoassay (TIA) tests. A large number of human serum and immunized guinea pig serum samples were tested against this antigen. In comparison, ELISA was found more sensitive than the TIA technique. The potent antigen fraction I used in these tests was lyophilized at an optimum concentration of 1 mg/ml for obtaining uniform results.

Toxoplasmose aguda: avaliação da técnica de imunoensaio em camada delgada para a detecção de anticorpos IgM, anti-Toxoplasma gondii

A solid phase method, thin-layer immunoassay (IgM-TIA) was standardized and evaluated for the immunodiagnosis of acute toxoplasmosis, through the detection of IgM antibodies to Toxoplasma gondii. A total of 300 serum samples from serologically defined acute toxoplasmosis and, from non-related infections, was investigated by IgM-TIA. Statistical analysis were carried out in comparison with conventional tests, the immunofluorescence test for the detection of IgM antibodies (IgM-IFI) and hemagglutination test which uses 2-mercaptoethanol serum treatment (2ME-HA). Also the correlation coefficients were calculated for various Toxoplasma gondii antigen concentrations, as well as, the influence of the antigenic concentration on the relative indices of sensitivity and specificity were verified. The intra and inter test reproducibilities were demonstrated statistically, as well as, the reutilization of T. gondii antigen was proven to be possible for at least 10 times. The data indicated that antigenic concentrations, from 70 to 100 Cmg/ml, were able to provide maximum sensitivity and specificity. IgM-TIA displayed similar diagnostic efficiency to those two conventional tests here utilized, and may be employed to make diagnosis of acute toxoplasmosis, mainly if laboratory animals are available.

Comparison of dot enzyme-linked immunosorbent assay (dot-ELISA), passive haemagglutination test (PHT) and thin layer immunoassay (TIA) in the diagnosis of natural or experimental fasciola hepatica infections in sheep

The dot enzyme-linked immunosorbent assay (Dot-ELISA) was compared with the passive haemagglutination test (PHT) and thin layer immunoassay (TIA) for the detection of antibodies against Fasciola hepatica in naturally and experimentally infected sheep. The infected animals gave titres from 1:25 000 to 1:204 000, while control animals gave titres of from 1:100 to 1:800. The titres of the infected sheep obtained by Dot-ELISA were 1000–2000 times higher than the ones obtained using TIA or PHT. Due to its high sensitivity, this technique could be very useful for the diagnosis of ovine fascioliasis.

Application du test à la vapeur à la détection et au dosage immunologique de l'entérotoxine thermolabile de Escherichia coli

Summary The principle of this thin-layer immunoassay (vapour condensation technique or TVAP) is based on the ability of antibodies to absorb firmly to polystyrene surfaces and to retain their reactivity. A condensation pattern consisting of large confluent water drops is noticable when an antibody-antigen reaction takes place. We used this technique to detect and assay the Escherichia coli heat-labile enterotoxin (ETEC LT+) and compared the results of 53 strains (40 positives and 13 negatives) with single radial immune haemolysis, Gm1-ELISA and Vero cell culture tests. With the reagents used, this reaction was specific for a toxin dilution up to 1/14. As little as 0.025 μg/ml of cholera toxin could be detected. The TVAP-test is simple, rapid and cost-effective. It is thus quite suitable for use in diarrhoeal endemic areas.

Detection of Opiates in Postmortem Tissues by Thin-Layer Immunoassay

The use of thin-layer immunoassay (TIA) for the detection of opiates in postmortem brain, kidney, liver, and lung tissue has been developed. The method is simple to perform, requires no specialized equipment or radioactive reagents, and is sufficiently sensitive for the detection of opiates in postmortem tissues. Sample preparation consists of homogenization followed by ultradialysis to remove protein. The procedure was evaluated in a blind study of 83 postmortem tissue specimens and found to be reliable at tissue concentrations greater than or equal to 200 ng/g as determined by radioimmunoassay (RIA).

Paper discs impregnated with capillary blood. A sampling technique for immunoassays by means of DIG-ELISA and DIG-TIA

A modification of the diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) and the diffusion-in-gel thin layer immunoassay (DIG-TIA) using paper discs impregnated with blood or serum as source of diffusion is described. Using a BSA-anti-BSA model system the suitability of this sampling and assaying technique for simple and accurate quantitation of antibodies has been demonstrated. Paper discs impregnated with blood or serum and subsequently dried could be stored at temperatures between +4 °C and +37 °C for at least six weeks without significant loss of antibody activity. Application of paper disc DIG-ELISA was exemplified by assaying anti-BSA antibodies in rabbits immunized with BSA as well as antibodies against both soluble egg antigen and adult worm extract in mice experimentally infected with Schistosoma mansoni cercariae. The simplicity and good reproducibility of this technique should make it an attractive alternative in serological screening of large population groups. Definite advantages of this technique are the possibilities to analyse quantitatively antibodies in capillary blood, rather than serum from venous blood samples, and to store sampled material for a considerable time even under such climatic conditions as often prevail in tropical countries.

The Detection of Protein p30 in Seminal Stains by Means of Thin-Layer Immunoassay

The detection of p30 by means of an indirect thin-layer immunoassay (TIA) is described. Extracts from 20 samples can be analyzed in approximately 2 h with a detection limit of approximately 50 ng. The p30 protein was detected in seminal stains which had been stored at room temperature for six months and at 130 degrees C for 4 h. Blood, saliva, urine, perspiration, and tears did not interfere with the method. The reliability of the method was demonstrated in a blind study.

New trends in the rapid serodiagnosis of leptospirosis

TR/Patoc slide test, ELISA and TIA (Thin-Layer Immunoassay) were evaluated for their use in a rapid serodiagnosis of human leptospirosis. The results obtained indicated that the TR/Patoc slide test is very sensitive and able to detect within a few minutes early antibodies against whichever serovar of leptospires, like the antigens of the Galton test. The value of the ELISA test in detecting antibodies at a low level is confirmed. The TIA assay, employed here for the first time for the diagnosis of leptospirosis, though sensitive seemed too long to perform and consequently it is not a test of choice for a rapid screening of sera.

The Detection of Fetal Hemoglobin in Bloodstains by Means of Thin-Layer Immunoassay

A method for the detection of fetal hemoglobin in bloodstains by means of thin-layer immunoassay is described. The equivalent of 0.01 microL of blood containing 0.18 to 0.24 microgram of fetal hemoglobin may be detected by this method. Studies with stains up to two years old and blind studies have shown these methods to be sufficiently sensitive and specific to be of value in forensic serology.

Detection of opiates in blood by thin-layer immunoassay.

The use of thin-layer immunoassay (TIA) for the detection of opiates in postmortem blood samples has been developed. Samples required no preparation other than protein removal, which was accomplished easily by the use of a commercially available ultrafiltration device. The procedure was evaluated in a blind study of 82 postmortem blood samples and found to be reliable. Opiate was detected in these samples at a RIA-determined concentration as low as 10 ng/mL.

Studies of antibodies to lipid A and Tamm-Horsfall in patients with inflammatory bowel disease.

Sera from patients with inflammatory bowel disease, ulcerative colitis (UC), or Crohn's disease (MC) were analysed for antibodies to lipid A and Tamm-Horsfall protein (TH), Escherichia coli O antigens, and food antigens, using enzyme-linked immunosorbent assay, indirect haemagglutination, and thin-layer immunoassay, respectively. C-reactive protein (CRP), an indicator of acute inflammation, was also studied. The MC and UC groups were not separated by any of the factors tested. The extent of the disease, however, seemed to influence the IgG antibody response to lipid A and TH. Patients with extended inflammatory areas in the intestine had decreased anti-lipid-A levels during the active phase of the disease compared with patients with less inflammation. In contrast, the IgG anti-TH levels were increased in these patients during both the active and inactive phases compared with less affected patients. Compared with healthy individuals, MC or UC patients showed decreased IgG anti-lipid-A levels. Both IgG and IgA anti-TH and total anti-O levels were increased compared with controls. Antibodies to cow's milk were lower in patients with inflammatory bowel disease than in the control group. CRP was increased in patients with active inflammatory bowel disease compared with inactive.

Comparison of TIA with ELISA for circulating antibody detection in clonorchiasis

A comparison was made of a new serological method, thin layer immunoassay (TIA), and an established method, enzyme-linked immunosorbent assay (ELISA), in the detection and quantification of antibodies in clonorchiasis. Saline extract of lyophilized Clonorchis sinensis adult worm was used as antigen, and TIA by the method of Elwing et al. (1976) and ELISA by Voller et al. (1974) were performed. Using sera from known clonorchiasis cases, 100 % of the sera tested were positive by TIA and 88.3 % by ELISA. TIA produced false positive results in 14 out of 36 cases, which were 10 amoebiasis cases, 16 paragonimiasis cases and 10 healthy controls. ELISA, however, produced a small number of false positives, 7 out of 55 cases. There was correlation between immunoglobulin G level in sera and ELISA value (correlation coefficient, 0.69), whereas no correlation between immunoglobulin G level and TIA result. The performance of TIA and ELISA was not correlated in the results using homologous antigen.

Thin Layer Immunoassay (Tia) For Circulating Antibody Detection In Clonorchiasis

Thin layer immunoassay was carried out to demonstrate antibodies against Clonorchis sinensis in sera from clonorchiasis patients. Saline extract of adult worm was used as antigen. TIA technique was performed as described earlier by Elwing et al. (1976), but agarose was used instead of agar. The antibody titres of sera in 60 clonorchiasis cases were higher than that of 10 healthy and 10 amoebiasis cases, but not different comparing with that of 10 paragonimiasis cases. Antibody titres in clonorchiasis gave no differences according to the age, sex, EPG in feces, eosinophilia degree of blood, level of alkaline phosphatase and transaminase (SGOT, SGPT) in sera. It is suggested that, after evaluation, the TIA might supplement or be used as an alternative to other immunodiagnostic tests already in use for the diagnosis of clonorchiasis.

Detection of opiates in urine by means of thin-layer immunoassay.

The use of thin-layer immunoassay (TIA) for the direct detection of opiates in unextracted urine is described. This novel immunoassay is capable of detecting less than 1 ng of opiates, rapidly and inexpensively, without the use of radioactive materials or sophisticated analytical instrumentation. The method was evaluated in a study of 68 post mortem urines and found to be reliable for the detection of opiates in this type of sample.

A comparison of thin layer immunoassay (TIA) and enzyme-Hnked immunosorbent assay (ELISA) for the detection of antibodies to Trypanosoma cruzi

The enzyme-linked immunosorbent assay (ELISA) was compared with a new solid phase method, thin layer immunoassay (TIA) for the serodiagnosis of Chagas's disease. 156 sera from Brazilian adult patients who were subject to investigation for chronic Chagas's disease, and 100 sera from healthy Swedish blood donors were analysed. There was a very good agreement between the methods with regard to positive and negative results and it is concluded that either method could be used for sero-diagnosis of Chagas's disease depending upon the choice and facilities of the particular laboratory.

Thin-layer immunoassay: A novel method for the detection of drugs in urine

Thin-layer immunoassay: A novel method for the detection of drugs in urine

The Identification of Human Bloodstains by Means of Thin-Layer Immunoassay: A Preliminary Report

The application of thin-layer immunoassay to the problem of human bloodstain identification is described. The differentiation of human, dog and rabbit bloodstains has been achieved by this method with the use of anti-human haemoglobin serum.

Diffusion-in-gel thin layer immunoassay (DIG-TIA): Optimal conditions for quantitation of antibodies

A new technique for the quantitation of antigen-antibody reactions, diffusion-in-gel thin layer immunoassay (DIG-TIA), has been developed. The principle of DIG-TIA is that antibodies are allowed to form a concentration gradient by radial diffusion in an agar gel poured on top of an antigen-coated plastic surface. After removal of the gel and visualisation by means of condensation of water vapour on the plastic surface, the antigen-antibody reactions appear as zones of increased wettability. The concentration of antigen used for coating, pH of the agar, incorporation of Tween 20 in the agar, size of diffusion basins, time of diffusion, and reinforcement by anti-immunoglobulin have been studied with regard to their influence on sensitivity and precision in the detection of antibodies with DIG-TIA. A photographic technique for permanent recording of wettability patterns is also described.