The detection of antibodies to Mycobacterium tuberculosis by microplate enzyme-linked immunosorbent assay (ELISA).
ABSTRACT The detection of antibodies to Mycobacterium tuberculosis by enzyme-linked immunosorbent assay has proved to be a potentially useful technique for the serodiagnosis of tuberculosis. The technique is capable of full automation. The use of a purified antigen should further improve the sensitivity of the method.
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ABSTRACT: Increased incidence of extrapulmonary tuberculosis (EPTB) as co-infection is observed due to rise in human immunodeficiency virus (HIV) infection. However, the precise diagnosis of EPTB is faced with difficulty due to the lack of tissue biopsy or fine-needle aspiration cytol- ogy (FNAC) facilities in rural hospitals. Enzyme linked immunosorbent assay (ELISA) will be simple, convenient and doesn't require sophisticated laboratory. Mycobacterial antigens ES-31, ES-43 and EST-6 antigens were isolated from Mycobacterium tuberculosis (M. tuber- culosis) H37Ra bacilli by affinity chromatography. Cocktail of these antigens and their affin- ity purified antibodies were explored for detection of antibody and antigen by Indirect and Sandwich ELISA respectively. In a preliminary study with bacteriologically confirmed EPTB cases (n=32), assay of antibody/free antigen/immunecomplexed (IC) antigen showed a sensitivity of 100% and specificity of 90%. Based on this study, sera from suspected EPTB patients (n=164) diagnosed by clinical and other laboratory investigations, non-tubercular disease patients (n=75) and healthy controls (n=75) were screened. A sensitivity and specific- ity of 72% & 91% for antibody detection, 70% & 94% for circulating free antigen and 63% & 98% for circulating IC antigen detection were observed. On combining the positivity of antibody, circulating free and IC-antigen, overall sensitivity of 96% and specificity of 91% were observed in EPTB. Tuberculous antibody detection to cocktail antigen was found to be useful in detection of EPTB. However, circulating free and IC-antigen detection may be a better marker for detection of different groups of EPTB.
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ABSTRACT: Sera from 123 patients with confirmed tuberculosis and 576 patients with other non-mycobacterial diseases were tested for antibodies to an adsorbed mycobacterial sonicate antigen employing an enzyme-linked immunosorbent assay. The results show significant differences in IgG levels between sera from tuberculosis patients and controls. The results of delayed hypersensitivity skin-test reactions to purified protein derivative in both the patient and control groups were unrelated to antibody levels. The assay was able to detect antibodies for at least 4 months after diagnosis and treatment. Patients diagnosed as having tuberculosis 7 months or more before being tested did not demonstrate increased antibody levels. The assay could be useful not only as a screening technique for diagnosing tuberculosis in an immunised population but also as a means of monitoring antituberculosis treatment.South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde 03/1987; 71(3):154-6. · 1.70 Impact Factor
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ABSTRACT: There have been numerous unsuccessful attempts to develop clinically useful serodiagnostic tests for tuberculosis. Although the large number of published reports clearly show that antibody levels are significantly higher in patients, as a group, than in a control population, little consideration is given to the value of the tests in various operational situations. In this paper we review the criteria generally used to assess the usefulness of a diagnostic test and introduce two new concepts--namely, operational predictive accuracy and operational acceptability.Bulletin of the World Health Organisation 02/1990; 68(5):571-6. · 5.25 Impact Factor