Some autoimmune diagnostics companies offer screening kits which purport to offer "meaningful" quantative assay results. While this quantitation may seem to be an advantage for the laboratory, quantitative screening kits provide no actual clinical utility.

There are several reasons that INOVA does not offer quantitative screening kits.

1. Screening kits, by their very nature must be qualitative. The definition of a "screen" is to differentiate one state of being from another. This requires that the result be a binary answer... yes/no, +/-, 1/0, positive/negative, etc.

2. Quantitation requires a meaningful standard to reference against. In the case of an ANA screening test, no recognized or meaningful standard exists since ANA is a conglomeration of many autoantibodies. While a few autoantibody analytes (dsDNA for example) have recognized standards, most do not and many still remain uncharacterized. To offer quantitation of uncharacterized analytes makes no sense, and may even imply a higher level of specific results where none actually exist.

3. The correct purpose of a screening kit is to efficiently remove negative samples from the population of patients to be tested. Patient sera for which screening tests are requested are, for the most part, clinically uncharacterized. Once the sample status is known (positive/negative), the laboratory can then focus on the positive patients for follow-up with further specific autoantibody testing. Follow-up testing will be required anyhow since, with the exception of multi-plex assays, the specific autoantibody(s) yielding the positive result(s) still remains to be identified [multiple unique, positive analytes can often be present in autoimmune diseases]. Of what use is quantitation when one does not know what they have even been quantified?

4. Good laboratory practice does not include quantitative screening assays. One of the most basic premises taught in Medical Technology programs is the difference between sensitivity and specificity. The recognized protocol is this... first perform a sensitive, qualitative screening test followed by a specific quantitative test. To do the reverse makes the chance of reporting false positive results a real possibility.

For questions, concerns or comments regarding this website, please contact Donna at: dlg@inovadx.com