ProPublica has been documenting the myriad ways the health system wastes money on unnecessary services, often shifting the costs to consumers. But there are ways patients can protect themselves.

We consulted the bill-wrangling professionals at Medliminal, one of a number of companies that negotiate to reduce their clients’ charges for a share of the savings.

After years of jousting with hospitals, medical providers and insurers, their key advice for patients and their families is to be assertive and proactive.

Here Are Seven Steps Patients Can Take To Protect Themselves:

1. Make sure the proposed test or treatment is necessary. Ask what might happen if you didn’t get the service right now.
2. Ask the price before the test or treatment. (Prices may not be negotiable if they’re set by an insurance company contract.)
3. Write on your financial agreement that you agree to pay for all treatment provided by providers who are in-network, which means they have set rates with your insurance company. (The medical providers may not accept the altered form.)
4. If possible, get the billing codes the medical provider will use to charge you and contact your insurance provider to make sure that each code is covered.
5. If you are having a procedure see if you can get the National Provider Identifier and/or Tax ID number of the surgeons, anesthesiologists, and their assistants. Contact your insurance company to see if the providers are in-network, which results in the negotiated rates.
6. Demand an itemized bill, and then look at each specific charge. Medical bills are often riddled with errors.
7. Ask if the provider has a financial assistance policy, which could result in a sliding scale discount. Many people qualify, and discounts can range from 20 to 70 percent.