parse oid string result

Dear Sirs,

how can i insert and handle an OID that returns a string through the web interface?

The result string using the snmpget command is SNMPv2-SMI::enterprises.2.3.51.3.1.5.20.1.11.1 = STRING: "Normal"

How can i parse this result and make an alert checker to send me an email if the result is not "Normal"?

Best Regards