Dutch insured patients are free to choose a doctor or hospital themselves. After all, the health insurer has to pay a part. Those who go to a non-contracted provider (eg the StatenClinic) must first advance the amount themselves. You can then declare the bill to the health insurer.

The amount of the reimbursements depends on the policy you have taken out. With a reimbursement policy ('restitutiepolis'), you will be reimbursed the rate that the health insurer has set for the treatment.

For a 'naturapolis' you usually pay less premium and the reimbursements are lower. The Health Insurance Act (see Article 13 Healthcare Insurance Act) states that health insurers do not always have to reimburse the entire amount. In practice, this means that the insured, who goes to a non-contracted provider (eg the Staten Clinic), has to pay part of the treatment himself. The health insurer therefore only partially reimburses. The legal text states that a small fee is mandatory.

Background information:
1) Article 13 Healthcare Insurance Act