Communication is key when going through airport security. (MANDEL NGAN/AFP/GETTY IMAGES)

With all the long lines, the unpredictable flight schedules and the resulting flaring tempers, going through airport security can be stressful for even the most unencumbered traveler. If you have a disability or a medical condition, your anxiety level may be even higher, especially if you have to travel with special medical equipment or supplies.

To help passengers with special needs understand what they can expect during screening, the Transportation Security Administration offers tips for more than two dozen conditions or scenarios, from traveling with a service dog to carrying diabetes medications.

The agency also runs a toll-free hotline called TSA Cares (1-855-787-2227). “They have information on what to expect at the checkpoint, and they can clarify what the screening procedures will be,” said Kimberly Walton, assistant administrator for the civil rights and liberties at the TSA.

The specially trained call-center employees can help arrange assistance at the airport, which is one reason the TSA recommends that passengers or their family members contact the hotline at least 72 hours before a trip.

Still, even with all the training TSA officers get, Walton said, it’s important that travelers realize that “no one is more of an expert on their needs than they are.”

Here are some tips to help you become more of an expert on security procedures:

Communicate. Tell TSA representatives if you have equipment or a condition that will affect what you or they need to do during screening. If you’d prefer to be more discreet, you can present them with a notification card (downloadable from the TSA Web site) to inform them of your needs. (The card won’t exempt you from screening, though.)

Know what’s in your bag. When you’re used to carrying something around, it’s easy to forget that you have it. Before you get in line, think like a stranger and go over everything that might be worth mentioning. Walton said that one of the biggest challenges for security staff arises when passengers neglect to tell TSA officers about medically necessary liquids or devices.

Understand the liquid rules. Medically necessary liquids are exempt from the 3.4-ounce container limit. Keep them separate from other items during screening, and inform the officers if liquids would be compromised by being opened for examination.

Don’t be a hero. If you have problems walking or standing, or if you use a mobility device such as a wheelchair or a scooter, there’s no need for you to struggle to do more than you feel physically capable of. If you have a choice, going through a metal detector requires less time on your feet than the imaging machines. If you can’t stand or walk through either of those, you’ll be screened during a pat-down.

Avoid the metal muddle. If you have a metal implant, you probably know whether it will set off the metal detector. If it will, choose the imaging machine or a pat-down instead.

Talk to your doctor before you leave. Travelers with certain internal medical devices or other items, such as radioactive implants, may need to avoid specific types of screening. People on oxygen should know whether they can disconnect from their equipment. It’s best to go over these types of concerns with your doctor well in advance.

Keep your cool. Items for keeping medically necessary liquids, gels or aerosols cold are allowed through security. They’ll be subject to the same screening as liquids or gels unless they’re frozen solid.

Stick together. If you’re traveling with someone who needs your help, whether it be a child or an adult with physical or intellectual disabilities, ask to be allowed to stay with the person. The special-needs traveler has to go through the metal detector or imaging technology on his or her own, but a travel companion may accompany the person during a pat-down.

Fido will need to be screened, too. Service dogs can be screened by metal detector or pat-down. The dogs can go ahead of, behind or with their owners, who won’t be separated from the animals.

Be aware of your options. If you have a cast or prosthesis, you may be able to be screened with a new imaging system that has been deployed at a number of airports, including Reagan National. The technology is slightly different from the standard imaging machines and, for example, allows officers to see through a cast.

Find the right line. Some airports have lines dedicated to travelers with disabilities and medical conditions. If one isn’t available, and you anticipate difficulties waiting in the queue, you can request to go to the front of the line, either through TSA Cares or by asking on-site staff.