Rising health-care costs threaten your finances. Unfortunately, when it comes to trying to cut those costs, you're often on your own.

While having health insurance is essential to safeguarding your net worth, having that insurance doesn't mean you can stop paying attention to the costs of health care. For example, your insurer won't always get everything right, especially for hospital visits and other extensive treatment. Insurance companies sometimes initially deny coverage for claims that their policies actually cover.

You also can't count on your doctor to fight for you. Often, they're too busy fighting insurance companies themselves. For instance, doctors in New Jersey have settled class-action lawsuits after alleging unfair business practices against several insurers, including WellPoint (NYSE: WLP), Cigna (NYSE: CI), and Aetna (NYSE: AET). But according to the Medical Society of New Jersey, doctors still face resistance from UnitedHealth Group (NYSE: UNH), which has continued to litigate claims.

Similarly, hospitals and other health-care centers don't always look out for your best interest. Outpatient surgical centers, which portray themselves as low-cost alternatives to hospitals, sometimes end up charging more for some procedures. Meanwhile, drug companies such as GlaxoSmithKline (NYSE: GSK) and Bristol Myers Squibb (NYSE: BMY) have had to pay millions to settle allegations that include price-fixing and other questionable practices.

How to defend yourself
When you're up against big insurance companies and medical institutions, you may feel powerless. But there are many things you can do to fight against high health-care costs. Here are just a few:

  • Negotiate up front. Part of why having health insurance is valuable is that your insurer usually negotiates with doctors and hospitals to charge less for covered patients. But even if you're not covered, you can negotiate the same deals. According to a Consumer Reports survey reported in U.S. News & World Report, fewer than a third of patients have tried negotiating, yet almost everyone who has tried was successful in cutting costs by at least a small amount.
  • Check the bills. Have you ever seen a bill for a hospital stay? There are usually pages and pages of details, combining various treatments and medicines in a format that's often nearly impossible to read. Yet by learning what you're being charged for, you can challenge the common mistakes that inflate your bill. Some insurance companies even offer rewards if you find a mistaken charge.
  • Know what's covered. For non-emergency care, it's smart to call your insurer beforehand to find out whether there will be any problems down the road. Although insurers won't usually make coverage decisions over the phone, get the name of the person you talk to, and follow up your conversation with a letter that explains your understanding that your insurance will pay for your treatment.
  • Consider other sources. Many doctors and hospitals offer free or low-cost screenings and other services from time to time. Taking advantage of them can save you a lot of money. In addition, you can sometimes find traveling medical professionals who visit a city for a weekend and offer discounted medical tests at a fraction of their usual cost.

With medical costs always on the rise, you need to save every dollar you can. By taking charge of your health expenses, you can fight to cut costs and keep more money in your pocket.

You can learn more about saving on health-care costs by reading about

Our Budgeting & Saving Center can give you plenty of other tips on how to save on everyday expenses.

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Fool contributor Dan Caplinger got a 10% discount from his dentist last month. He doesn't own shares of the companies mentioned in this article. UnitedHealth Group is a Stock Advisor recommendation, and GlaxoSmithKline is an Income Investor selection. The Fool's disclosure policy always tells you how it is.