Medicare Part A vs Part B: a clean-submission checklist

Medicare splits into two billing worlds, and that split shapes how every claim is built. Part A pays for institutional services: the facility side of a hospital stay, skilled nursing, home health, and hospice. Part B pays for professional services: physician work, outpatient care, labs, and durable medical equipment. They use different forms, different electronic transactions, and different edits. A claim that is clean for one can be rejected outright as the other. If your billing process treats "Medicare" as one payer with one ruleset, rejections can surface quickly.

Two forms, two transactions

The cleanest way to keep Part A and Part B straight is to anchor each claim to the form and electronic transaction behind it.

• Part A — institutional. Part A claims are billed on the UB-04 (CMS-1450) and transmitted as the 837I institutional claim. This is the facility claim, where revenue codes, type-of-bill, occurrence and value codes, condition codes, and statement-covered dates carry much of the weight. Diagnoses are reported with ICD-10-CM. Inpatient procedures are reported with ICD-10-PCS.
• Part B — professional. Part B claims are billed on the CMS-1500 and transmitted as the 837P professional claim. This is the clinician claim, where CPT/HCPCS procedure codes, modifiers, place of service, rendering and referring provider NPIs, and units are reviewed line by line.

Both are x12 transactions moving through a clearinghouse to the Medicare Administrative Contractor (MAC), the regional contractor responsible for processing Medicare fee-for-service claims. Collectively, MACs process more than a billion Medicare fee-for-service claims each year. Both claim types also return as an 835 electronic remittance advice (ERA) that has to post cleanly. But the information that makes each claim acceptable is different, which is why the clean-submission checklist has to be split.

Part A clean-submission checklist

For an institutional claim, the edits that matter most are usually structural. The facility coding framework has to be in place before the claim goes out. Before an 837I is submitted, confirm:

• Type-of-bill is correct for the facility and frequency, including admit-through-discharge, interim, replacement, or void.
• Revenue codes are present and paired correctly with HCPCS where the MAC requires it, with accurate units and charges on each line.
• Occurrence, value, and condition codes are included when the bill type or claim circumstances require them.
• Statement-covered period dates align with admission, discharge, and any spell-of-illness logic.
• Billing and attending NPIs are present and valid, and the patient status or discharge status code is accurate.
• ICD-10-CM diagnoses and, when applicable, ICD-10-PCS procedures support medical necessity and align with relevant NCD/LCD policy.

Part B clean-submission checklist

For a professional claim, the edits tend to cluster around procedure lines, modifiers, provider data, and medical necessity. Before an 837P is submitted, confirm:

• CPT/HCPCS codes are valid for the date of service, with correct units and place of service.
• Modifiers are accurate and supported, including laterality, bundling, NCCI procedure-to-procedure edits, MUE unit limits, and any modifier required by an LCD or NCD.
• Diagnosis pointers connect each service line to a supporting ICD-10-CM code, and medical necessity supports the billed service under the applicable LCD/NCD coverage policy, which can be searched through the Medicare Coverage Database.
• Rendering, billing, and referring or ordering provider NPIs are present and valid where required.
• CLIA numbers are included for lab services when applicable, and required documentation or authorization data elements are populated.
• Coordination of benefits is correct when Medicare is secondary under MSP rules.

A useful rule of thumb: Part A rejections usually start with the facility coding structure. Part B rejections usually start with procedure, modifier, provider, or medical-necessity logic. Knowing which claim type you are working with tells you where to look first.

How AcuraClaim handles both

AcuraClaim supports Medicare Part A & Part B submission as one of its five front-of-cycle solutions, while treating them as the distinct claim types they are. The system builds the institutional claim as an 837I and the professional claim as an 837P. It applies the correct framework to each and runs its pre-flight checks against current CMS rules before the claim leaves, so corrections happen up front instead of coming back as avoidable rejections.

From there, AcuraClaim submits the claim through the clearinghouse. When the remittance arrives, the system posts the 835 electronic remittance advice (ERA). Because CMS rules change, the edit logic is maintained against current policy rather than frozen at setup. And because AcuraClaim is built for the front of the revenue cycle, the scope is clear: it helps get Part A and Part B claims out clean and accepted. It does not work denials, file appeals, call the MAC, or chase A/R. That work stays with your team. Any acceptance or first-pass figures AcuraClaim cites are drawn from its own operating model, never from patient data.

If your Medicare mix spans institutional and professional claims, and you want to see the right edits run before submission, book a demo.