"that's big"
Sure is, total number of health care workers worldwide is 59 million in 2006 according to WHO figures.
http://www.u21health.org/meetings/nottingham2006/docs/conference/15_Modern_Health_Work_Liz_Fradd.pdf
And CST only needs to sell a bare 5 million tests a year at US$20 a test to be a cash cow earning about 40cps???