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 medication errors. One reason these mistakes persist: Only 15% of hospitals are fully computerized with a central database to track allergies and diagnoses, says Robert Wachter, chief of the medical service at University of California San Francisco Medical Center.

But signs of change are emerging. More than 3,000 U.S. hospitals, or 75% of the country's beds, signed on for a 2006 campaign by the Institute for Healthcare Improvement implementing new prevention measures such as multiple checks on drugs. In the first 18 months of the campaign, these hospitals had prevented an estimated 122,300 avoidable deaths.

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. "Getting out of the hospital doesn't mean you're out of the woods."

A study released last week by Resources for the Future, a nonprofit group that conducts independent research on public health issues, says that infections of sepsis and pneumonia acquired in the hospital may kill 48,000 people each year. What s more, the study shows, these infections cost $8.1 billion to treat and lead to 2.3 million total days of hospitalization.

Such revelations, along with the recent increase in antibiotic-resistant bugs and the mounting cost of health care, 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 or her 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 a 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. Most hospitals now have rapid response teams teams of specialized personnel that can rush to the bedside to assess a declining patient. Haskell urges patients to know the hospital hierarchy, read name tags, get the attending physician's phone number, and know how to reach the rapid response team. 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 Dr. Mark Friedman, founder of billing consultant Premium Healthcare Services. That leaves room for some bargaining.

If you re among the uninsured who can pay up to three times more for procedures it doesn t hurt to ask for a deduction. Some hospitals provide a 35% to 40% discount for uninsured patients, says Candice Butcher, CEO of Medical Billing Advocates of America. 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.

If you don t have insurance and are scheduled for a colonoscopy in a week, Butcher suggests doing some research to find out how much that procedure typically runs in your area. The site healthcarebluebook.com lets consumers check health-care prices by zip code. You can use that as a negotiation tool. But remember, if the hospital agrees to your price, you need to get it in writing and get it signed, says Butcher.

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.

If you're alert enough, ask for someone in your network. If you re seeing a physician or going to any medical facility, call your insurance company for a current list of network physicians, hospitals and labs. Also, if the referral appointment is being made by your primary-care physician, request the scheduling staff to find specialists, hospitals and labs in your network. Then verify that with your insurance company, says Mary Jane Stull, president and CEO of The Patient s Advocate, a South Bend, Ind., firm that helps people with medical insurance claims. Medical providers can drop out of a network between the preoperative appointment and the actual surgery date. And if you know your procedure will be out-of-network, call the medical providers: physicians, surgeon, anesthesiologist, and hospital. It might be worthwhile to try to negotiate a price and payment plan with the billing department, Stull 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, which shouldn't 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 vs. a vein which can come to a difference of thousands of dollars.

So how do you figure out if your bill has incorrect codes or duplicate charges? Start by asking for an itemized bill with a breakdown of all charges clearly defined, says Dr. Geni Bennetts, principal of Resolve Healthcare Billing Advocacy in Napa, Calif. 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 billadvocates.com).

Their expertise typically will cost anywhere between $65 and $85 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, there will be a deficit of about one million nurses. 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.

For information on specific hospitals, visit its web site at www.healthgrades.com

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.

A good tool to help consumers evaluate hospitals is a web site operated by the Department of Health & Human Services, which compares hospitals against national averages in certain areas. The site includes information about how well hospitals care for patients with certain medical conditions as well as the results of surveys given to patients asking them about their stay, says Anne F. Weiss, a senior program director at the Robert Wood Johnson Foundation, a health-care nonprofit.

8. "Most ERs are in need of some urgent care themselves."

A 2007 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.

Nearly three-quarters of ER directors reported inadequate coverage by on-call specialists vs. 67% in 2004, according to a 2006 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're having severe symptoms, such as the worst headache of your life or chest pains, a triage nurse is trained to recognize if your symptoms constitute a medical emergency. Just know that emergency department staff are strained during busy hours, but giving honest descriptions of your symptoms, and truly working with the staff is the best way to advocate for yourself and your family as a patient, says Darria E. Long, a doctor at Yale s department of emergency medicine.

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, some 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 8 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.

10. "Sometimes we don't know how to 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 they will readily share those details with insurance companies for payment purposes. That means roughly millions of 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 an old episode of 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. For your own "Patient Privacy Toolkit," visit the Patient Privacy Rights Foundation's web site at www.patientprivacyrights.org.