Q: Can ELISA test diagnose tuberculosis and neurocysticercosis?

A:ELISA is a good diagnostic test for neurocysticercosis, with a high sensitivity and specificity. However, the same cannot be said about ELISA test for tuberculosis (TB), which is a poor test to diagnose TB since it has a low sensitivity and specificity, with consequently poor negative and positive predictive values. However, ELISA for extrapulmonary TB (involving organs / systems other than lungs) may be of some help in diagnosis, but only when all three antibodies, IgG, IgM and IgA, are done simultaneously, and then too the report has to be interpreted in the light of the patient's clinical condition and other supportive investigations.