The Q:

Mel Hildebrand of Baltimore scolded us last week after we advised readers about which government agencies can require you to give your Social Security numbers, and how others request it but don't necessarily have a right to it. (The answer if you missed it: Some government agencies, including tax authorities, welfare offices and state Departments of Motor Vehicles, can require your number as directed by federal law.)

Hildebrand didn't have a problem with the answer. He just had a bone to pick with the way one government agency abuses his precious nine digits.

"Everyone seems to be missing the largest area of vulnerability ... Medicare card numbers in the hands of old (over 65) and disabled, vulnerable citizens," Hildebrand said in his e-mail. "The [Social Security] Administration has protected us by making states issue driver's licenses with unique numbers, not SSNs as in the past. Then Medicare sends everyone over 65 or disabled a card that has their SSN on it and it has to be presented to every doctor and hospital that they see.

"Doctors' offices and hospitals with high turnover and paper files are now the resting place for our precious SSN!" he added. "Sometimes, only a low counter in a waiting room separates anyone in the room from our SSN. How many times is there a waiting room, check-in counter, our files and no one behind the desk? A perfect setting for SSN theft!"

Hildebrand concluded by asking why those "folks in Congress" aren't closing this "GIANT loophole?"

The A:

Here's hoping Hildebrand won't chew us out for delivering some bad news.

Privacy rights advocacy groups have long urged Congress to remove your personal digits from Medicare cards. Unfortunately, that effort has not gone anywhere yet.

"To qualify for Medicare, you must also qualify for Social Security so the two go together," said Peter Ashkenaz, a spokesman for the Centers for Medicare and Medicaid Services. "It's your primary U.S. identification number, so that's why we use it."

CMMS is aware that carrying the card can be risky, but Ashkenaz says, "The tip we give people is to treat your Medicare card like you would treat a credit card. You have to carry it in case of an emergency. If you have to go to an emergency room, you'll need your Medicare card to get full benefits and proper care."

While that is good advice, it's also important to understand that losing your wallet to a thief or by accident isn't quite the same when the contents include your Medicare card and credit cards. With credit cards, you can call the 800 numbers to close those account numbers. With a Medicare card, losing your Social Security number could expose you to criminals who could open new accounts in your name or draw on your existing bank accounts.

Although there was a push a few years ago by Congress to limit the use of SSN by government agencies for identification purposes, the move stalled when it was discovered that the cost and effort of issuing new Medicare cards without those numbers would be prohibitive.

"With 44 million Medicare beneficiaries, you're dealing with a very large undertaking," Ashkenaz said. "The cost of doing an overall change is extremely high. It is a topic that we in Social Security have been looking at, but no conclusions have been reached. It's a hard issue."

The Privacy Rights Clearinghouse suggests that you photocopy your Medicare card and then cut out or use a black marker to cross out the last four digits of your number. If your wallet is stolen, this will help minimize your risk.

But the clearinghouse also warned that you probably need to bring your original Medicare card with you the first time you visit a health care provider. Ashkenaz also warned that if you're in an emergency and are unable to share the last four digits of your Medicare card, you might not receive all benefits.

Should you lose your Medicare card, be sure to call 800-MEDI- CARE or 800-633-4227 in order to put a watch on your billing information and then request a fraud alert through the credit agencies. Be sure to monitor your credit reports for unusual activity and consider requesting a freeze on your credit reports.

Reach Consuming Interests by e-mail at consuminginterests@baltsun .com or by phone at 410-332-6151. Find an archive of Consuming Interest columns at baltimoresun.com/consuming