What does it mean to have an S in front of the medical insurance card?

Hello, honey, don't worry about it. XS is normal. Because the last digit of the medical manual number is usually the English letter "S", the last digit of the social security card number is usually Arabic numerals or the letter "X", but the first nine digits are the same as the medical manual number, which will not affect the insured's medical treatment. X means the same as yours. Not yet. This won't affect your medical treatment. Just use it directly.