Key Components
There are four pieces of information that generally need to be engraved on a medical id alert bracelet: diagnosis or condition, allergies (if any), patient's name, and emergency contact. There are also things that aren't needed, such as the patient's address (unless they have dementia) and social security number.
Personal Information
Most people prefer to have personal information out of sight, so it's most common to have the patient's diagnosis and allergies engraved on the front of their ID bracelet, and their name and emergency contact on the back. (note: although not all medical id providers offer two-sided engraving, most medical id bracelets can be engraved front and back, and that provides more room for engraving).
Emergency Contact
When deciding whose emergency contact phone number to engrave on a medical id, try to select the individual who is most likely to be available to take the call. It's unwise to use someone who travels frequently, or who frequently has to allow their calls to go to voice mail. Many people screen their calls and only answer those from numbers they recognize. The person whose phone number is used on the back of a medical id bracelet will need to be someone that's willing to answer incoming calls even when the caller id is unrecognized. Note: if there's not enough room for diagnosis, allergies, patient name, and phone number, the patient's name can be eliminated, but it would be better to find a different bracelet that offers more room for engraving.
See Other Side
If any diagnosis or allergy information is being engraved on the back of a medical bracelet and the medical id would have to be removed from the wrist in order to see the back side, it's best to add the words 'See Other Side' on the front. It may use up a line of engraving, but it helps to insure that the paramedic will know that there's more medical information on the back. If the reverse side of the bracelet can be viewed easily without having to remove the bracelet from the patient's wrist, then it's probably not necessary to add 'see other side'.