NEW YORK (MainStreet) – If you're even considering traveling abroad without at least looking into whether your health insurance will cover you in another country, just tack a few thousand dollars onto the cost of your excursion.

You'll need it.

"It's actually very important to consider, because most people will spend months planning for a trip, but they never plan for the unforeseen, and it's very difficult to do so. You may get sick overseas, you may get involved a car accident overseas — which is very common — or some sort of severe weather or natural disaster causes a flight cancellation, you lose your luggage, you miss a flight, your gear gets stolen. Any of these things can have a real impact on your travel, and if you're not insured you can have real financial hardship," says Ed Perkins, consumer advocate and insurance expert for online travel pricing and advice site SmarterTravel.

Many U.S. citizens have health programs that include charges outside the country, Perkins says, and typically, these folks do not need special travel coverage for ordinary medical expenses.

"Nevertheless, they might want to buy some insurance,” he says.

Both the Centers for Disease Control and the State Department's Bureau of Consular Affairs strongly agree. The CDC's Theresa E. Sommers suggests, at some length, preparing for a trip abroad by looking into travel insurance, travel health insurance and medical evacuation insurance.

The State Department takes it a step further by supplementing the CDC's suggestions for coverage from International SOS, Medex and the International Association for Medical Assistance to Travelers with a full list of U.S. and foreign insurance providers, calling medical and travel evacuation insurance “absolutely necessary.” The U.S. embassy or consulate can help find medical services, tell family and friends and assist in transfer of funds from home, but they can't pay for expenses.

While travel insurance is typically used to cover lost baggage and trip cancellations, the CDC notes that travelers may be more likely to avoid travel when sick if they know their financial investment in the trip is protected. While it won't cover medical care or medical transportation, even that base level of insurance is intrinsically tied to a person's health.

“With travel insurance, it is vital that anyone buying it take advantage of the insurance company’s system for waiving the exclusion for pre-existing medical conditions,” Perkins says. “Usually, that means buying the insurance within a week or two of the initial trip deposit and payment and covering the entire nonrefundable portions of the trip cost.”

When considering medical insurance, however, travelers should consult the State Department's online information sheet for the country they're traveling to and see what it says about the medical system there. As the State Department representative noted, in many countries — even many of those with socialized medicine — you're required to pay upfront, cash for treatment. That may not be covered by medical insurance, and you may have to call back to the U.S. to check with an insurance provider to see if a treatment or procedure is covered — which isn't always ideal when you're in the middle of a medical emergency.

Those are issues you'll want to have sorted out well before your departing flight takes off. The CDC suggests checking in with your insurance company before your trip and investigating their exclusions on preexisting medical conditions, policy for out-of-network services and (if necessary) coverage for complications of pregnancy or birth. You're definitely going to want to have a conversation with your provider to see if high-risk activities such as skydiving, scuba diving and mountain climbing are covered — if that kind of activity is a possibility — or if it'll cover psychiatric emergencies or injuries related to terrorist attacks or acts of war. At the very least, see if you'll need to check in with the provider for hospital admission, seek a second opinion before emergency treatment or if you'll be able to reach a doctor through its 24-hour support center. Students traveling abroad should go through the extra step of seeing if their parents' insurance company addresses any of the above.

Finally, in the event your injury or condition is so terrible that you need to be evacuated out of the area and back to the U.S., the CDC and State Department recommend medical evacuation coverage. Domestic insurance companies typically don't cover this, and the cost can vary wildly depending on where you're traveling. The State Department sets a baseline of $50,000 worth of evacuation coverage, but notes it can be less in places such as Western Europe or far more in remote areas. The CDC says that, at its worst, a medical evacuation could cost a traveler upward of $100,000.

“Emergency evacuation covers extraordinary expenses of getting someone home after a medical problem,” Perkins says. “The folks who sell this stuff constantly issue press releases about someone who broke his or her butt and had to charter a business jet to get them home. Most 'bundled' travel insurance includes enough evacuation to suit most needs, but a few folks won’t take the risk and buy extra.”

Even providers that do cover such services don't do so evenly. Before buying evacuation insurance, the CDC implores travelers to consider services that guarantee hospitals are paid directly directly, have a 24-hour doctor-backed call center, have at least the equipment that a medical transport company in the U.S. would and have specific services that cover higher-risk activities.

So what does all this cost, you ask? A quick scan of the Medex offerings found plans ranging from $3.50 a day to more than $500 a month depending on your age and where you're traveling. They vary widely and can be based on the length of your trip or over a specific period of months or years. That said, they're not particularly hospitable to everyone.

Medicare, for example, does not cover anything outside the U.S., but Medicare supplement policies offer some overseas coverage. The caveat is that you'll have to pay upfront for care and be reimbursed when you return.

“Most pricing is age-related, so coverage can become virtually unaffordable for travelers in their 80s and 90s,” Perkins says.

Also, they don't cover every contingency. The State Department notes that many of the worst incidents abroad don't involve natural disasters, terrorism or even medical emergencies, but car accidents.

“Very often, trips end in grief due to car accidents,” the State Department spokesman said. “If you're considering driving overseas or renting a vehicle, make sure people are cognizant of the dangers they may face with unfamiliar traffic patterns or roads and definitely make sure you're properly insured for liability and other issues.”

— Written by Jason Notte in Portland, Ore., for MainStreet.

To follow the writer on Twitter, go to http://twitter.com/notteham.

This article is commentary by an independent contributor. At the time of publication, the author held TK positions in the stocks mentioned.