(Paul Taylor/iStock)

Traditional medical alert systems can get help when you have an accident at home. But now there are mobile devices sold with the promise that they can also connect you with a rescue team for medical emergencies that happen when you’re out and about.

They do that in two ways. First, those gadgets — which are essentially like basic cellphones — link you to an emergency call center with the push of a button. Second, if you’re unable to talk or you’re lost, the devices use Global Positioning System technology (GPS) to find you.

That sounds reassuring, but the newer products have drawbacks. They may not work as well indoors as a traditional system — and most falls and medical emergencies occur in the home, according to the National Safety Council. Their performance depends on a strong cellular connection, which may be weaker indoors. So if you don’t have good wireless coverage in your home or residential community, a mobile system may not be for you. And the GPS feature may not function well indoors.

In addition, the devices need to be recharged often, and they usually cost more than traditional home-based systems. Finally, a regular cellphone with an emergency call feature provides one of the same benefits that a mobile alert system does.

Still, the one-button simplicity and the GPS feature can be appealing, especially if you’re at higher risk for falls or have a chronic health condition and if you spend time away from home alone. Mobile alerts “can give a sense of security,” says Alfred Sacchetti, a spokesman for the American College of Emergency Physicians.

If you opt for a mobile alert system, look for:

●A cellular phone network that works well in your area. (For Consumer Reports’ Ratings, see here.)

●A 3G or 4G network.

●Easy-to-use buttons.

●A neck pendant or belt clip to hold it.

●A system that has its own U.S. monitoring center, with trained emergency operators (rather than an outside contractor).

●A monitoring center certified by Underwriters Laboratories.

A look at 5 leading systems

The mobile medical alert systems listed below (which Consumer Reports didn’t test) are handheld, weigh about two ounces each and offer neck pendants or belt holders, which may cost extra. They’re GPS-enabled and have 3G service and two-way speakerphone communication around the clock. In all cases, an operator will call someone in your contact group and get emergency help if needed.

Tip: Try to negotiate. Prices can change and salespeople can be aggressive, so print a copy of prices and terms from Web sites before you call. Information was current as of August 2015.

Bay Alarm Medical Mobile GPS (877-522-9633).

Monthly service: $40

Device and activation fee: $80 plus shipping

GreatCall Splash (800-650-5921).

Monthly service: $20, $35 with fall detection

Device and activation fee: $85 plus shipping

LifeStation Mobile GPS (855-701-0968).

Monthly service: $30

Device and activation fee: $50

Medical Guardian Premium (800-724-5845).

Monthly service: $50

Device and activation fee: None

Mobile Help Solo (800-992-0616).

Monthly service: $38

Device and activation fee: None

Copyright 2015. Consumers Union of United States Inc.

For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.