The Payment Card Industry's (PCI - https://www.pcisecuritystandards.org/) Data Security Standard imposes uniform conditions on any organization that processes or handles credit cards. The PCI was formed by Visa, MasterCard, American Express, Discover, and JCB International to help combat security breeches and disclosure of personal credit card information throughout the credit processing chain.
The standard imposes various levels of auditing based on the number of transactions per year with a card issuer and prior history. The Merchant Level Table shows the various level requirements and auditing requirements.
Level two through four merchants can perform self validations. PCI defines five types that determine which validation form needs to be filled out. The form walks you through your options and which type is correct for you.
Daly Realism can help you fill out your self-validation form and design and implement your remediation efforts. A free basic self assessment questionnaire is provided. This highlights areas that frequently cause problems and provide some advice for remediation.