LA Times Front Page - JWs Treated Without Blood

I am just a little confused . Randy's article states that 

Then in 1978 they openly allowed factor VIII (platelets) after allowing them in secret for some years to callers.

Whole platelets would indeed be prohibited under current WTS ruling. Checking a couple of sites though they say that factor viii is taken from plasma, which is different.

Perhaps this could be explained to a layman like me?