Why do specialties refer without basic investigations

Question to the hive mind. why do senior doctors particularly a&e but not exclusively,refer patients to specialties without basic investigations eg. chest X-ray or arterial blood gas in the context of hypoxia. This is the level id expect of a newly qualified f1 yet for some reason these investigations often have to be suggested to the referring clinicians. Be interested to gain perspective on this, clearly everyone is busy but this stuff is just so basic