What does Block 31 require on the CMS-1500 form?

• A. The signature of the physician or supplier to verify that the claim is correct.
• B. The date of service.
• C. The patient's ending diagnosis.
• D. The facility's address.

Answer: (A)

Block 31 is the provider’s attestation line. It requires the physician or supplier to sign to certify that the claim information is correct and that the services were actually provided as billed. This signature acts as authorization to submit the claim and holds the signer accountable for the accuracy of the data on the form. The date and other details are captured in different blocks, so the signature in this block specifically serves as certification, not the service date, diagnosis, or facility address. In paper claims, it’s typically an ink signature; electronic claims use the provider’s signed-on-file or electronic signature instead.