Even though roughly a large majority of Americans have some form of health insurance, understanding what exactly is covered by your policy is another story. Representatives are readily available via insurance companies’ 800 numbers, online sites, and even social media pages to discuss specific policy details. But while many health insurance companies are subjective in deciding which services they will pay for, there are a few major categories of services typically considered universally “covered” or “not covered” by health care insurance.

What’s Covered

Most policies cover all forms of emergency care, including emergency room visits, emergency surgery, and emergency hospitalization, where the situation is literally life or death. This classification is easy to determine, since by nature, emergencies are unplanned and assumed to be through no fault of the insured. Obviously, having confirmation in advance that emergency services are completely covered by your policy comes in handy, as you should assume you will not be able to navigate your policy coverage in the middle of an emergency situation. In fact, most health insurance providers will also pay at least some of the costs for a non-emergency hospitalization, such as basic room and board costs.

Many health insurance companies cover doctor out-patient visits, as those are necessary for basic maintenance and wellness. Even if you stipulated a co-pay for office visits in your health insurance plan, many insurance providers now offer free annual “wellness” or “well-woman” gynecological exams for women, as well as limited screenings and scans for early disease detection.

As awareness of the benefits of early detection increases, more health insurance providers are learning that including preventative coverage is good for their own interests as well. By providing coverage for screenings of most kinds of cancer and other chronic diseases, health insurance companies will likely save money in the long run, protecting themselves from having to pay out more money later if the patient develops the disease and requires extended or ongoing treatment. Most health insurance providers pay for basic disease prevention screenings, and in many cases, your insurance provider may even pay for some of your treatment for a chronic condition. For example, cancer treatment may be covered, although it is likely the insurer would implement a “cap” to limit their liability once your expenses exceeded maximum costs for treatment. However, “cap” laws may be changing, as per recent changes in health care reform, according to CNN.

Gray Areas of Coverage

Coverage for non-life-threatening surgical procedures varies from one insurance provider to the next, but typically, “elective” surgeries ? otherwise known as optional surgeries performed for non-medical reasons, which the patient elects to undergo ? are not covered. Common exceptions sometimes include semi-elective procedures or weight-loss surgeries. However, in general, insurance companies that cover gastric bypass surgery, lap band procedures, or IVF treatments are less common.

Many other services are left entirely to the discretion of individual health insurance providers. Some treatment services previously offered by most insurance companies, like mental health care, substance abuse treatment, physical therapy, and maternity care, are increasingly rare. Often, insurance providers will include a specific clause about a seemingly marginalized medical cost. However, a company that provides comprehensive enough coverage to include prosthetics, for example, is something that should be investigated on an as-needed basis.

What’s Not Covered

As a rule, reconstructive and/or cosmetic surgeries are not covered by most health insurance providers. This is because whereas you may unexpectedly require surgery to save your life in an emergency, or to save your life down the road or improve the quality of it, such as the case with a mastectomy or gastric bypass, insurance companies do not view cosmetic procedures as absolutely necessary to your health and well-being. The list of cosmetic procedures not covered by most health insurance companies includes, but is not limited to, skin grafts, laser hair removal, breast augmentations, rhinoplasty, and liposuction.

If you are in immediate medical need of an organ transplant, check your health insurance policy. Chances are, there is no guarantee this procedure will be covered. Since this is usually considered an elective surgery, and the availability of organ donors is a complicated process, insurance providers cannot come up with a uniform set of costs or liabilities from patient to patient. This means that transplant coverage varies per health insurance company. Only 45% of providers currently cover organ and tissue transplantation, according to the New York Times.

Ongoing treatment for chronic diseases may also not be covered. Patients in need of services to treat diabetes, cancer, heart disease, arthritis, and obesity currently account for over 75% of all health care costs in the U.S., and future “cap” law reformations may open up more insurance options for them. However, treatments for infertility and sterilization are not receiving much health insurance support these days. Fewer than 30% of health insurance companies provide coverage for such services.