Can antibody tests be used to make a diagnosis?
Not effectively for two reasons. First, we are all constantly exposed to fungi of various sorts. As we discuss elsewhere, there are fungi in the air around us at all times. You might very well have antibody response to those fungi. This has an important implication: just because you (a) find fungus X under your refrigerator and (b) have an antibody response to fungus X doesn’t mean that the antibody response is due to the fungus under your refrigerator! A second problem has to do with the relative lack of specificity of many of the antibodies against fungi. Many of the fungi are closely related and antibodies that appear to be against fungus X might actually have been induced by exposure to fungus Y. Stated more scientifically, antibodies against fungi may both lack specificity and be cross-reactive. The extent of these problems for any given test for any given antibody will vary, but the general principle is that antibody tests are of very limited utility in making a diagnosis.
