When working with regular expressions, it is considered a best practice to test the expression with the OnBase Regex Validator, available from Hyland Community or your solution provider. This helpful tool allows you to validate regular expressions and to view examples of the types of data typically captured by the Intelligent Capture for AP module.
If you know the full range of PO # values for your solution, it is considered a best practice to configure a custom regular expression to allow the Intelligent Capture for AP engine to more easily identify and extract these values, thus reducing processing time.