Nine of the 15 medical networks surveyed featured informal categories of doctors, such as "leading specialists" and "specialists," Vadomusti writes. In six networks, the difference in the cost of the initial appointment between the categories exceeds 150%, while some doctors under VHI can be reached only at your own expense or after additional authorization. Insurers call this practice hidden price increases: Clinics increase the average bill without changing rates, leading to higher policy prices.