Not 幽默

來源: Vaccine 於 2006-09-12 11:54:47 [] [舊帖] [給我悄悄話] 閱讀數 : (292 bytes)

it is not 幽默, it is true.
the so called TB test is a PPD test which does not test the TB directly, it tests the immunity agaist the TB.In China if you get the vaccine and you still keep the PPD negative you have to get the vaccine again till your PPD becomes positive. Is it simple?

請您先登陸，再發跟帖！