How Many Hairs Do You Need to Pull For a Hair Pull Test

Dr William, in a hair pull test , If i gently pull around 60 hairs, so on how many hairs extracted out will the hair pull test be positive? I mean to ask if one pulls gently around 60 hairs so how many hairs will come out for the hair pull test to be positive?

Generally one does a pull test for the diagnosis of telogen effluvium. Usually pulling gentle on 10 hairs will yield a positive test if more than three of them come out.