(in the US) If I have a doctor that is not in my health insurance's network (and so listed as Not-Covered), or if my doctor prescribes a drug that is not covered, I understand the insurer will normally not pay the cost. However, if I have already paid as much as the annual out-of-pocket maximum for the plan isn't the plan responsible for all further costs (regardless of source)? Or am I always responsible for all out-of-network costs regardless of how much I've already paid this year?
The portion of the billing that falls under the "allowed amount" will be captured by your out-of-pocket max, which may be different from your in-network out of pocket max.
This is the way it generally works assuming your plan has an out of network benefit. Considering an out of network 60% co-insurance; say you receive a bill for $5,000 from an out of network provider, for a service that is covered by your policy.
$5,000 Total Bill
$3,000 Allowed Amount
$1,800 Carrier portion of coinsurance (60% of $3,000)
$1,200 Your portion of coinsurance (40% of $3,000)
$2,000 Balance bill in excess of the allowed amount.
Your total exposure here are the bold amounts, $1,800 and $2,000. The $1,800 will be applied to your out-of-pocket max. The $2,000 balance bill is ignored by the carrier as it exceeds the allowed amount.