Hi SOC you could be right about this but then again its not necessarily regular NK function or numbers that appear to be the predominant marker, but the ratio of bright to dim cells. Bright cells are NK cells that have been fully activated - on duty as it were. Most NK cell function tests may be looking at combined function rather than bright cell function. When this test is improved, expect to see our views changing, because this could be a major step forward. However this will not be a simple or cheap test using the tech I am familiar with: the NK cells have to be stained and then examined. This means people or expensive machines.