If using a secondary insurance, whose information needs to be recorded in Block 4?

In the context of using a secondary insurance when submitting the CMS-1500 claim form, it is essential to document the correct individual responsible for the primary coverage. Block 4 is designated for the "Insured's Name," which refers specifically to the primary insured individual under the insurance policy that is being billed first.

When dealing with secondary insurance claims, the primary insurance is billed initially, and the details of that coverage must be accurately recorded. Therefore, including the name of the primary insured in Block 4 helps in confirming their association with the primary policy, ensuring that the claim is processed smoothly and that the secondary insurer can coordinate benefits appropriately.

This is crucial because if the wrong information is provided, it may lead to delays or denials in claim processing, as the insurers rely on accurate identification of the insured to understand coverage specifics, benefit levels, and obligations for payment. The other options do not pertain specifically to the primary insured's information, which is why they do not fit this context.