ABSTRACT
SETTING: The diagnosis of bone and joint tuberculosis (BTB) is difficult, and diagnostic delays often occur. A reliable serological test detecting anti-mycobacterial antibodies would thus be of some use in this form of the disease. OBJECTIVE: To evaluate the diagnostic accuracy of an assay detecting IgG against 38-kDa and 16-kDa recombinant mycobacterial antigens in BTB. MATERIALS AND METHODS: In a prospective study, serum samples from 124 subjects were examined: 30 BTB cases, 40 non-specific bone and joint infection patients (NSBI), 30 lung cancer patients (LC), and 24 healthy volunteers (HC). An ELISA-based test (Pathozyme TB complex plus) was used. RESULTS: The cut-off level was established at 150 U/ml according to receiver operating characteristic (ROC) curves. The quantified level of sensitivity of the test detecting BTB was 56%, at a specificity of 99%. The positive and negative predictive values were respectively 94% and 88%. Mean IgG level in the BTB group was 470 +/- 761 U/ml (mean +/- SD), and was significantly higher than the antibody level in the control groups (NSBI 58 +/- 42 U/ml, LC 43 +/- 38 U/ml, HC 40 +/- 29 U/ml). CONCLUSION: The test presents an acceptable level of sensitivity and very good specificity in the diagnosis of BTB, and can be used in combination with other methods to increase diagnostic accuracy in this disease.
Subject(s)
Antigens, Bacterial/immunology , Immunoglobulin G/blood , Lipoproteins/immunology , Tuberculosis, Osteoarticular/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Bacterial/analysis , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Sensitivity and SpecificityABSTRACT
Despite of a fast development in the techniques of rapid identification of mycobacteria by molecular genetic techniques, serodiagnosis may be of special values as non-expensive, easy to perform method. Several serodiagnostic tests, principally those using immunoenzymatic (ELISA) methodology are available. The goal of our study was to evaluate one step coloured immunochromatographic assay detecting IgG antibodies against antigen 38 kDa (Rapid Test TB). Our material consisted of 278 serum samples--tuberculosis (n = 155), healthy (n = 36), sarcoidosis (n = 50), lung cancer (n = 25) mycobacterial infections other than tuberculosis (n = 12). Tuberculosis group consisted of new culture positive cases (n = 66), new culture negative cases (n = 23), chronic cases (n = 43) and extrapulmonary TB (n = 23). Specificity of 96% and sensitivity of 54% was obtained. In pulmonary TB sensitivity of 50% and in extrapulmonary TB of 74% was obtained. In chronic cases sensitivity of 70% and in new cases of 40% was received. Sensitivity of 44% in new culture positive cases and 30% in new culture negative cases was obtained. We conclude that immunochromatographic test may be a very useful tool improving tuberculosis diagnosis, especially in extrapulmonary tuberculosis. Strip test may be an interesting alternative as it is an extremely simple, rapid, and cheap technique.
Subject(s)
Chromatography/methods , Immunoglobulin G/analysis , Serologic Tests/methods , Tuberculosis/diagnosis , Chromatography, High Pressure Liquid , Enzyme-Linked Immunosorbent Assay , Humans , Sensitivity and SpecificityABSTRACT
Measurement of antimycobacterial antibody may be used as potential diagnostic tool in tuberculosis. The aim of the study was to evaluate the diagnostic value of serum IgG level against A60 mycobacterial antigen measured by ELISA method. Material consisted of 144 persons divided into 5 groups (76 tuberculosis patients, 20 sarcoidosis patients, 17 lung cancer patients, 8 patients with mycobacterial infections other than tuberculosis and 23 healthy controls). In the tuberculosis group there were 50 culture positive cases and 26 culture negative ones, 43 new cases and 32 chronic cases. Positive results were obtained in 51% of tuberculosis patients. Sensitivity increased to 62% in culture positive group and 63% in chronic cases. Specificity of the test was 96%. The results indicate that Immunozyme Mycobacterium test is a valuable tool in tuberculosis diagnosis.
Subject(s)
Antigens, Bacterial/analysis , Immunoglobulin G/blood , Membrane Glycoproteins/analysis , Tuberculosis/diagnosis , Adult , Aged , Biomarkers/blood , Diagnosis, Differential , Female , Humans , Lung Neoplasms/diagnosis , Male , Middle Aged , Mycobacterium Infections/diagnosis , Sarcoidosis/diagnosis , Sensitivity and Specificity , Serologic Tests , Tuberculosis/immunologyABSTRACT
Tuberculosis diagnosis bases on clinical and radiological symptoms and identification of mycobacteria. Accuracy of both methods is limited. Therefore reliable serological test would have considerable advantage. The present study was aimed at evaluating IgG-mediated immune response against specific mycobacterial antigens 38 kDa in group of 200 patients and control subjects. Our material consisted of 104 tuberculosis patients, 25 with sarcoidosis, 24 with lung cancer, 13 with bacterial or fungal pulmonary infection, 8 with mycobacterial infections other than tuberculosis and 26 healthy persons. We used commercially available ELISA based kits (Pathozyme TB-complex). Specificity of 100% and sensitivity of 49% was achieved. Sensitivity increased to 59% in chronic cases and to 52% in culture positive cases. Sensitivity decreased to only 14% in group of new culture negative cases. Measurement of IgG serum level against 38 kDa can be helpful in tuberculosis diagnosis. As the test lacks falsely positive results it indicates its high positive predictive value.
