If a suspected card account number passes the Mod 10 test, what does it indicate?

Passing the Mod 10 test, also known as the Luhn algorithm, indicates that the suspected card account number may be a valid Primary Account Number (PAN). This means that the number has a structure that could correspond to a legitimate card number, as it adheres to the mathematical formula used to verify the integrity of card account numbers.

However, passing the Mod 10 test does not guarantee that the PAN is indeed valid or active. Card numbers that pass this test could still be fictitious or inactive, as the check primarily serves to detect common errors in the number (such as miskeyed digits). Hence, validating a PAN is a more complex process that involves checking against issuer databases and other security measures. Therefore, the answer correctly reflects that while the number shows potential validity, further verification is necessary to confirm whether it is a legitimate card account.