1) “Oops, wrong kidney.”

In recent years errors in treatment have become a serious problem for hospitals, ranging from operating on the wrong body part to medication mix-ups. According to a report from the Institute of Medicine, at least 1.5 million patients are harmed every year from being given the wrong drugs — that’s an average of one person per U.S. hospital per day. One reason these mistakes persist: Only 10% of hospitals are fully computerized, with a central database to track allergies and diagnoses, says Robert Wachter, chief of the medical service at UC San Francisco Medical Center.But signs of change are emerging. More than 3,000 U.S. hospitals, or 75% of the country’s beds, have signed on for a campaign by the Institute for Healthcare Improvement implementing new prevention measures such as multiple checks on drugs. As of June these hospitals had prevented an estimated 122,300 avoidable deaths over 18 months.

While the system is improving, it still has a long way to go. Patients should always have a friend, relative or patient advocate from the hospital staff at their side to take notes and make sure the right meds are being dispensed.

2) “You may leave sicker than when you came in.”

A week after Leandra Wiese had surgery to remove a benign tumor, the high school senior felt well enough to host a sleepover. But later that weekend she was throwing up and running a fever. Thinking it was the flu, her parents took her to the hospital. Wiese never came home. It wasn’t the flu, but a deadly surgical infection.About 2 million people a year contract hospital-related infections, and about 90,000 die, according to the Centers for Disease Control and Prevention. The recent increase in antibiotic-resistant bugs and the mounting cost of health care — to which infections add about $4.5 billion annually — have mobilized the medical community to implement processes designed to decrease infections. These include using clippers rather than a razor to shave surgical sites and administering antibiotics before surgery but stopping them soon after to prevent drug resistance.For all of modern medicine’s advances, the best way to minimize infection risk is low-tech: Make sure anyone who touches you washes his hands. Tubes and catheters are also a source of bugs, and patients should ask daily if they are necessary.

3) “Good luck finding the person in charge.”

Helen Haskell repeatedly told nurses something didn’t seem right with her son Lewis, who was recovering from surgery to repair a defect in his chest wall. For nearly two days she kept asking for a veteran — or “attending” — doctor when the first-year resident’s assessment seemed off. But Haskell couldn’t convince the right people that her son was deteriorating. “It was like an alternate reality,” she says. “I had no idea where to go.” Thirty hours after her son first complained of intense pain, the South Carolina teen died of a perforated ulcer.In a sea of blue scrubs, getting the attention of the right person can be difficult. Who’s in charge? Nurses don’t report to doctors, but rather to a nurse supervisor. And your personal doctor has little say over radiology or the labs running your tests, which are managed by the hospital. Some facilities employ “hospitalists” — doctors who act as a point person to conduct the flow of information. Haskell urges patients to know the hospital hierarchy, read name tags, get the attending physician’s phone number and, if all else fails, demand a nurse supervisor — likely the highest-ranking person who is accessible quickly.

4) “Everything is negotiable, even your hospital bill.”

When it comes to getting paid, hospitals have their work cut out for them. Medical bills are a major cause of bankruptcy in the U.S., and when collectors are put on the case, they take up to 25% of what is reclaimed, according to Mark Friedman, founder of billing consultant Premium Healthcare Services. That leaves room for some bargaining.Take Logan Roberts. The 26-year-old had started work as a business analyst near Atlanta but had no insurance when he was rushed to the ER for an appendectomy. The uninsured can pay three times more for procedures, says Nora Johnson, senior director of Medical Billing Advocates of America; Roberts was billed $21,000. “I was like, holy cow!” he says. “That’s four times my net worth.”After advice from advocacy group The Access Project, Roberts spoke with hospital administrators, telling them he couldn’t pay in full. Hospitals frequently work with patients, offering payment plans or discounts. But to get it, you have to knock on the right door: Look for the office of patient accounts or the financial assistance office. It paid off for Roberts, whose bill was sliced to $4,100 — 20% of the original.

5) “Yes, we take your insurance — but we’re not sure about the anesthesiologist.”

The last thing on your mind before surgery is making sure every doctor involved is in your network. But since the answer is often no for anesthesiologists, pathologists and radiologists, what’s a patient to do? Los Angeles-based entertainment lawyer and patient advocate Michael A. Weiss repeatedly turned away out-of-network pain-management doctors on a recent visit to the hospital.We’re not suggesting you go as far as Weiss did to save money, but do ask for someone in your network if you’re alert enough. If it’s an emergency and you’re stuck with an out-of-network doctor, call your insurance company to help resolve the issue. If it’s elective surgery, ask a scheduling nurse in the surgeon’s office to find specialists in your plan, says South Bend, Ind.-based billing sleuth Mary Jane Stull. And if you know your procedure will be out-of-network, call the hospital billing department to negotiate. It will likely point you to a patient representative or the director of billing. Once you’ve dealt with the hospital, then try the surgeon or other specialists involved — some hospitals will back you in those discussions, Friedman says.

6) “Sometimes we bill you twice.”

Crack the code of medical bills and you may find a few surprises: charges for services you never received, or for routine items such as gowns and gloves that should not be billed separately. Clerical errors are often the reason for mistakes; one transposed number in a billing code can result in a charge for placing a catheter in an artery versus a vein — a difference of more than $3,900, Stull says.So how do you figure out if your bill has incorrect codes or duplicate charges? Start by asking for an itemized bill with “miscellaneous” items clearly defined. Some telltale mistakes: charging for three days when you stayed in the hospital overnight, a circumcision for your newborn girl or drugs you never received. Ask the hospital’s billing office for a key to decipher the charges, or hire an expert to spot problems and deal with the insurance company and doctors (you can find one at www.billadvocates.com). Their expertise typically will cost up to $65 an hour, a percentage of the savings or some combination of the two. If you want to be your own billing sleuth, talk to the highest-ranking administrator you can find in the hospital finance or accounts office to begin untangling any mistaken codes.

7) “All hospitals are not created equal.”

How do you tell a good hospital from a bad one? For one thing, nurses. When it comes to their own families, medical workers favor institutions that attract nurses. But they’re harder to find as the country’s nursing shortage intensifies — by 2020, 44 states could be facing a serious deficit. Low nurse staffing directly affected patient outcomes, resulting in more problems such as urinary tract infections, shock and gastrointestinal bleeding, according to a 2001 study by Harvard and Vanderbilt University professors.Another thing to consider: Your local hospital may have been great for welcoming your child into the world, but that doesn’t mean it’s the best place to undergo open-heart surgery. Find the facility with the longest track record, best survival rate and highest volume in the procedure; you don’t want to be the team’s third hip replacement, says Samantha Collier, vice president of medical affairs at HealthGrades, which rates hospitals.The American Nurses Association’s Web site lists “magnet” hospitals — those most attractive to nurses — and a call to a hospital’s nurse supervisor should yield the nurse-to-patient ratio, says Gail Van Kanegan, an R.N. and author of How to Survive Your Hospital Stay. She also suggests calling the hospital’s quality-control or risk-management office to get infection statistics and asking your doctor how frequently the hospital has done a certain procedure. While reporting these statistics is still voluntary, more hospitals are doing so on sites like www.hospitalcompare.hhs.gov, which compares hospitals against national averages in certain areas, including how well they follow recommended steps to treat common conditions, says Carmela Coyle, senior vice president for policy at the American Hospital Association.

8) “Most ERs are in need of some urgent care themselves.”

A new study from the Institute of Medicine found that hospital emergency departments are overburdened, underfunded and ill prepared to handle disasters as the number of people turning to ERs for primary care keeps rising. An ambulance is turned away from an ER once every minute due to overcrowding, according to the study; the situation is exacerbated by shortages in many of the “on call” backup services for cardiologists, orthopedists and neurosurgeons. And it’s getting worse. Currently, 73% of ER directors report inadequate coverage by on-call specialists, versus 67% in 2004, according to a survey conducted by the American College of Emergency Physicians.If you can, avoid the ER between 3 p.m. and 1 a.m. — the busiest shift. For the shortest wait, early morning — anywhere from 4 a.m. to 9 a.m. — is your best bet. If you are having severe symptoms, such as the worst headache of your life or chest pains, alert the triage nurse manager, not just the person checking you in, so that you get seen sooner, says David Sherer, an anesthesiologist and author of Dr. David Sherer’s Hospital Survival Guide. Triage nurses are the traffic cops of the ER and your ticket to getting seen as quickly as possible.

9) “Avoid hospitals in July like the plague.”

If you can, stay out of the hospital during the summer — especially July. That’s the month when medical students become interns, interns become residents, and residents become fellows and full-fledged doctors. In other words, a good portion of the staff at any given teaching hospital are new on the job.Summer hospital horror stories aren’t just medical lore: The adjusted mortality rate rises 4% in July and August for the average major teaching hospital, according to the National Bureau of Economic Research. That means eight to 14 more deaths occur at major teaching hospitals than would normally without the turnover.Another scheduling tip: Try to book surgeries first thing in the morning, and preferably early in the week, when doctors are at their best and before schedules get backed up, Sherer says.

10) “Sometimes we don’t keep our mouths zipped.”

Contrary to what you might think, sharing patient information with a third party is often perfectly legal. In certain cases, the law allows your medical records to be disclosed without asking or even notifying you. For example, hospitals will hand over information regarding your treatment to other doctors, and it will readily share those details with insurance companies for payment purposes. That means roughly 600,000 entities that are loosely involved in the health care system have access to that information. These parties may even pass on the data to their business partners, says Deborah Peel, the founder of Austin, Tex.-based Patient Privacy Rights Foundation.If you want to access your medical records, you don’t have to steal them like Elaine did on ‘Seinfeld’ after she learned a doctor had marked her as a difficult patient. You are legally entitled to see, copy and ask for corrections to your medical records.