Which of the following is true about Block 33a?

• A. It records the billing facility's address
• B. It records the payer’s policy number
• C. It records the NPI of the billing provider or group
• D. It records the patient's date of birth

Answer: (C)

Block 33a is where you enter the billing provider’s NPI—the 10‑digit National Provider Identifier that uniquely identifies the entity submitting the claim. This identifier links the claim to the correct billing provider or group and is the standard identifier used by payers in HIPAA transactions. It’s not used for the billing facility’s address, the payer’s policy number, or the patient’s date of birth, which appear in other sections of the form. So, recording the NPI of the billing provider or group is exactly what this field is for.