Short answer: Usually not. Most EPOs let you self-refer to in-network specialists. The catch is that EPOs cover in-network care only, with no out-of-network benefits except emergencies.
An Exclusive Provider Organization (EPO) blends HMO and PPO features: like a PPO it generally doesn’t require a PCP or referrals; like an HMO it covers in-network care only (emergencies excepted). That structure keeps premiums below a comparable PPO while still giving direct specialist access; as long as you stay in network. Going out of network usually means paying the full cost yourself.