Health insurance companies like to keep secrets. And they like to save money. Example: You have surgery, and weeks later you get a bill for using an out-of-network anesthesiologist. Ridiculous, right? You didnt choose who put you under, so you shouldnt have to pay extra. But your insurer sent the bill anyway, hoping you wouldnt notice.

Fighting back against this kind of trickery—and winning—is a lot easier than you think, says Kevin Flynn, the president of Healthcare Advocates, a Philadelphia-based firm that helps patients wrangle with their health plans. We checked with Flynn and other insurance-industry insiders, lawyers, doctors, and regulators to uncover nine little-known ways to get the health coverage you deserve—for less.

Dont pay if you dont have a say

When you purposely see an out-of-network doctor, your plan usually makes it clear that itll cost you. But when you have surgery, the hospital chooses the anesthesiologist. If you get that annoying “out-of-network” bill, Flynn says, draft a strongly worded letter stating you had no say about the anesthesiologist—in-network or otherwise—and, therefore, wont pay any additional fees.

“If you dont have direct control, you are not liable,” Flynn says, adding that this tactic is likely to work every time, but few consumers know about it.

You may be eligible for more coverage

Depending on your state, you could be eligible for more benefits than your plan is telling you about. Take Maryland, for instance. Health plans operating there must pay for expensive infertility coverage. But one state over, in Virginia, they dont. Its unlikely that your plan is trumpeting info about state-mandated coverage, though. Its up to you to get the scoop.

One good place to check is Families USA, a consumer group that keeps tabs on state rules, suggests Kevin Lembo, Connecticuts official health-care advocate for consumers. Another option: Contact your states insurance commissioner.

Next Page: When to advocate, when to hesitate [ pagebreak ]To get tested, talk up your symptoms

Your insurer doesnt want to pay for a colonoscopy if it thinks its not necessary. But if you believe you need one, heres how to get it covered: Talk to your doctor in detail about your symptoms and why you think you need the test. Your plan has to pay for it if you have gastro complaints, health experts say. (Only 21 states require insurers to cover colonoscopies for general screening.)

Stall first, answer questions later

When Wendy Decenzo became pregnant with twins, she wasnt worried about health insurance. Her husband, Chris, had made sure to get a health plan that covered pregnancy well before they started trying. But when Wendy began going for prenatal visits, coverage was denied. Their plan, Blue Cross of California, wouldnt say why. Instead, the insurer asked the Decenzos to sign release forms allowing the plan to view their medical histories, which the law says are private.

Chris believes the company was looking for any info that the Decenzos may have accidentally omitted when they applied for coverage. If an omission were to be found, the couple might have been denied coverage. “It seemed like a fishing expedition in order to deny us,” Chris says. So they refused to sign, and three months later the plan started paying for the prenatal appointments, even going back and paying for earlier visits that hadnt been covered. Flynn says lots of insurers try this trick, but since their review process usually lasts only 60 to 90 days, they often drop the inquiry after that. Sometimes, procrastination pays.

Next Page: Getting the most from your health plan [ pagebreak ]Letters are your best bet

It may seem a bit inconvenient, but the old-fashioned letter is by far the best way to communicate with your health plan. “Dont do anything over the phone. It takes forever and when youre done theres no record of it, so it didnt happen,” says Rhonda Orin, a Washington, D.C.–based attorney and the author of Making Them Pay: How to Get the Most From Health Insurance and Managed Care.

Letters almost always get a response, adds Lembo, the Connecticut health-care advocate. Some plans will answer email, but many wont. And to whom, exactly, should you address your mail? Experts recommend following your plans appeal process for letters and sending copies to your state insurance commissioner. Also, keep copies of every letter youve sent your plan and everything theyve sent back. That way, when your insurer says, “We never said wed cover that,” you can say, “I have it right here in writing.”

Doctors can be good weapons

You just got four massage sessions, under doctors orders, for lower-back pain—but your insurer refuses to pay for them? Ask your doctor for help. He can tell the insurer hes going to complain to the state board that regulates health plans.

“Health plans may not fear you, but they do respect the board,” says James Moss, MD, a retired Kentucky surgeon. He intervened on a patients behalf and, by pressuring the board, helped the patient win coverage. Another option: Say youll call your congressman and/or state Medicare office to lodge a formal complaint, Dr. Moss says.

Caveat: Dont actually contact your state board yourself if a claim is denied. Janice Weiss, a Jupiter, Fla.–based attorney who fights health plans for consumers, says some of her clients who went this route ended up hurting their cases when the state agency ruled their claims invalid; that left them little recourse with their insurance companies. Instead, while working your plans appeals process, just suggest you may take the matter to your state.

Next Page: Being proactive [ pagebreak ]A little research can go a long way

If you want a special CT scan or MRI, your doc probably wont authorize it unless its an absolute must. Persuade her with expert info from the American College of Radiologys Appropriateness Criteria, says Anne Roberts, the executive vice chair of the department of radiology at the University of California, San Diego.

Used primarily by doctors but open to the public, its an up-to-date list of the types of imaging that are right for various conditions. Arming yourself with the info doesnt guarantee coverage, but its a proactive step in the right direction.

There are ways to get drugs cheaper

Doctors are often wowed by the latest and greatest drugs, which tend to be the most expensive. Make sure these newer, high-end meds are what you need before you leave the doctors office. Sometimes your insurance plan wont pay for them at all; other times itll charge higher co-pays.

In many cases, drugs have generic versions that are just as effective but cheaper than the newer ones. Always ask your doc (or pharmacist) for generics. And if you really need a medicine that doesnt have a generic version, order it by mail. Many plans have a less-expensive mail-order pharmacy option. Another prescription trick for people who have chronic conditions like allergies: Ask your doc to write you a prescription for two or three months worth of medication instead of one. Good-bye, extra co-pays.

Next Page: Using an advocate [ pagebreak ]An advocate can help you win

Imagine being turned down for coverage after running up $125,000 in medical bills. Thats what happened to the parents of a daughter with anorexia just before they sought help from Kevin Flynn, of Healthcare Advocates. For $400, he took over the fight with their insurer and—after a years worth of combat—won.

Flynn is a patient advocate, part of a growing industry that makes its money from helping you. Some advocates help you interact with your doctor, while others specialize in insurance disputes. Most of all, firms like Flynns keep the letters going out on your behalf, saving you time, energy, and headaches. “The insurers know that advocates know the laws, the regulations—things a regular consumer might not know. That makes them nervous,” Flynn says.

Advocates can even get policies changed. One of Flynns clients, who had rectal cancer, was having trouble getting his insurance plan to pay for a new radiation therapy. The insurer claimed the treatment wasnt ready for prime time, but Flynn found six studies showing its usefulness for the disease, got the coverage—and got the insurer to rewrite its policy.