This is really an office policy/procedure question that needs to be sorted out asap!
The office needs to find an efficient way to verify benefits and if the deductible has been met. Most carriers have websites that are easy to check. That way the patient has no surprises when they show up for their appointment.
If you can't verify if the deductible has been met, you should at LEAST collect the co-pay. That will be the minimum the patient will have to pay. The office should also have a policy in place regarding payment of accounts so that can be gone over when the patient comes in, again, no surprises if they know what's required of them up front.
If the office takes several insurances, often, when the eob's come in, jot down the allowed amount as a sort of fee schedule. Then when the patient asks "how much is this going to cost?" you will be able to tell them "your insurance allows $xxx.xx for this procedure, you have a $xx.xx deductible, and if the deductible has been met you have a $xx.xx co-pay".
It's smart to at least collect something at the time of service, if something will be owing. "Endo" is not a specialty that people like going for, so they may really be unhappy with the cost of having something unpleasant done and may not want to pay the bill. So, again, POLICY and PROCEDURE are vital for the doctor and staff to have down! That way, no surprises and no offense taken when the bill comes!