ZertisMD

I recieved the following when I tried to add a new patient
with the following information.

Title: Mr.
First Name: John
Middle Name:
Last Name: Doe
Gender: Male
SSN:123456
Patient Number:

Fatal error: Call to undefined function: strip_ssn()
in /home/jlee/public_html/ZertisMD/modules/patients/pati
ent_add_action.php on line 9