cellestis with a lot of help from forrest, page-17

There are two arms to the adaptive immune reponse, humoral and cell-mediated, effected by different components of the body.
Currently, there are thousands of diagnostic tests on the market which measure the humoral response for an array of diseases and medical conditions, worth countless billions of dollars a year. Measuring this type of immunity is relatively easy because you just need to measure antibodies in serum. As far as Im aware, Quantiferon is the first type of diagnostic test to measure the cell-mediated response in a user-friendly way. This is why the motto of CST is measuring the other side on immunity. Previously this type of immunity has been difficult to measure, relying on complicated procedures suitable for research laboratories only.
Investing in biotechnology is inherently risky and it takes ages to get products on the market but there is no question that the technology of CST has enormous commercial potential and certainly its existing products are doing well (they are relatively low risk). Considering the science behind the companys technology, it is not unreasonable that the stock should appeal strongly to some.
Just thought Id add a little science to the debate.