Which block is recommended to be left blank on the CMS-1500 form?

Block 22 on the CMS-1500 form is specifically designated for "Resubmission code." This block is typically left blank unless the claim is a resubmission or there is specific guidance from a payer instructing the use of a resubmission code. For standard claims that are not being resubmitted, leaving this block blank is recommended to avoid confusion or processing delays.

The other blocks serve essential purposes; for example, Block 20 is used for the "Outside Lab" designation, Block 21 captures the diagnosis codes which are crucial for determining the necessity of services rendered, and Block 23 is utilized for the prior authorization number if required by the insurance carrier. Therefore, leaving Block 22 blank aligns with general guidelines and practices for submitting clean claims.