To find out, if your PDF is meeting the PDF/A standard you can use different validating tools. Adobe Acrobat contains the tool Preflight.

An Open-Source Software to validate PDF/A is veraPDF, a project by Open Preservation Foundation (OPF), PDF Association and Digital Preservation Coaliton.

The PDF Association also lists the following tools:

 Acrobat 8 Preflight (developed by callas software)

    PDF Tools AG: 3-Heights PDF Validator

    LuraTech: LuraDocument PDF Validator

    Seal Systems: PDF Checker

    Intarsys: PDF/A Live!

    callas: pdfaPilot

    callas: pdfInspektor

    Apago: PDF Appraiser (Actino)