You can open a PDF file like you would a text file. You can use the standard file functions (FileReadLine() etc.) to read in the data and search it for the values that you want (using MatchStr, StrPos etc.).
We actually needed to check the heading within the document, but it was not possible so we just check the tag.
We did not actually need to verify the contents line by line.
Do you need to read from this file?
Otherwise the tags for Adobe files are enough to verify the existence of the document.