O Button (blood Type) on LinkedIn

What it signals here

professional use

Not appropriate for professional communication; its use on LinkedIn would appear immature or confusing to most professional audiences.

post context

Might appear in posts by healthcare professionals discussing blood types, blood donation campaigns, or medical awareness content.

appropriateness

Generally inappropriate for professional contexts unless specifically discussing blood type-related health or medical topics.

comment use

Rarely used in comments; occasionally appears in health industry posts about blood donation or type-O universal donor awareness.

See it elsewhere