How to Correctly Fill Item 9A (Medigap) on the CMS-1500 Form for Medicare Claims

Published on March 19, 2024

How to Correctly Fill Item 9A (Medigap) on the CMS-1500 Form for Medicare Claims

Understanding how correctly fill item 9A on the CMS-1500 form is not merely a clerical task; it’s a critical component of efficient revenue cycle management, particularly when dealing with Medigap claims. Accurate completion of this field ensures that secondary payers, specifically Medigap plans, receive the necessary information to process claims promptly after Medicare has paid its portion. Errors here can lead to significant delays, increased administrative burden, and ultimately, a negative impact on your practice’s cash flow. This comprehensive guide will equip you with the detailed knowledge and practical steps required to master Item 9A, navigate the complexities of Medigap billing, and minimize common denial codes. —

Quick Reference Guide

For busy billers and coders, a quick reference can be invaluable. This table summarizes the essential information for correctly completing Item 9A and related fields for Medigap claims on the CMS-1500 form.
CMS-1500 Item Description Key Rule/Code Example/Guidance
Item 9A Other Insured’s Policy or Group Number Enter the Medigap payer’s name (e.g., “AARP Medicare Supplement”). This is crucial for identifying the secondary payer. AARP Medicare Supplement
Item 9B Reserved for NUCC Use Typically left blank for Medigap claims. Leave blank
Item 9C Medigap Policy Number Enter the patient’s specific Medigap policy number. This is distinct from their Medicare HICN. 1234567890 (as found on Medigap card)
Item 9D Insurance Plan Name Enter the full name of the Medigap insurance plan. This should match Item 9A if only one Medigap plan. AARP Medicare Supplement Plan G
Item 11 Insured’s Policy Group or FECA Number If the patient has a primary payer other than Medicare (e.g., employer group health plan), this is where that primary policy number goes. For Medigap, Medicare is primary. N/A (Medicare is primary for Medigap)
Item 11a Insured’s Date of Birth & Sex Required for the primary insured. MM | DD | YYYY | M/F
Item 11c Insurance Plan Name If Item 11 is used, this is the name of that primary insurance plan. N/A (Medicare is primary for Medigap)
Item 11d Is there another health benefit plan? Crucial for indicating secondary coverage. YES (for Medigap)
Item 13 Insured’s or Authorized Person’s Signature Signature on file for assignment of benefits to the provider. “Signature on File” or “SOF”

Detailed Breakdown

Navigating the intricacies of Medigap claims on the CMS-1500 form for Medicare claims requires a meticulous approach. This section delves deep into each aspect, from understanding the form’s structure to the nuances of electronic claim submission (EDI) and state-specific regulations.

The Anatomy of Item 9A on the CMS-1500 Form

The CMS-1500 form is standardized, but specific fields hold unique importance for secondary payers. Item 9, titled “Other Insured’s Name,” is where you identify any secondary insurance. For Medigap, this is where the Medigap plan information resides. It’s divided into sub-boxes (9A, 9B, 9C, 9D), each serving a distinct purpose.

Item 9A: Insured’s Policy Group or FECA Number (Medigap Payer Name)

Despite its label, for Medigap claims, Item 9A is where you enter the name of the Medigap insurance company. This is crucial. Medicare’s Common Working File (CWF) often contains Medigap information, and by correctly identifying the Medigap payer here, you facilitate the crossover process where Medicare automatically forwards the claim to the secondary insurer.
  • Example: If the patient has an AARP Medicare Supplement plan, you would type “AARP Medicare Supplement” in Item 9A. Do not enter the policy number here.
  • Item 9B: Reserved for NUCC Use

    This field is generally left blank for Medigap claims. It’s designated for specific National Uniform Claim Committee (NUCC) uses that typically do not apply to standard Medigap billing.

    Item 9C: Medigap Policy Number

    This is where the patient’s specific Medigap policy number is entered. This number is unique to their Medigap plan and is distinct from their Medicare Beneficiary Identifier (MBI). It is imperative that this number is accurate, as it’s the primary identifier for the Medigap insurer to locate the patient’s policy.
  • Example: A typical Medigap policy number might be a series of digits and/or letters, e.g., “1234567890” or “ABC-987654”. Always refer to the patient’s Medigap insurance card.
  • Item 9D: Insurance Plan Name (Medigap Payer Name)

    Similar to Item 9A, this field is used to reiterate the full name of the Medigap insurance plan. While it might seem redundant with 9A, it provides an additional point of identification for the secondary payer. Ensure consistency between 9A and 9D.
  • Example: “AARP Medicare Supplement Plan G” or “Blue Cross Blue Shield Medigap Plan F”.
  • Identifying the Correct Medigap Payer and Policy Information

    The accuracy of your billing errors hinges on correctly identifying the Medigap plan. This often requires more than just a quick glance at an insurance card.

    Understanding Medigap Plan Types (F, G, N, etc.) and Their Relevance

    Medigap plans are standardized by letters (A, B, C, D, F, G, K, L, M, N). While the type of plan (e.g., Plan F, Plan G, Plan N) dictates what benefits are covered (e.g., Part A deductible, Part B excess charges), it doesn’t directly change how you fill Item 9A. However, understanding the plan type is crucial for patient education and for anticipating what the Medigap plan should pay after Medicare. For instance, Plan F covers the Part B deductible, while Plan G does not. This knowledge helps in reconciling payments and understanding Explanation of Benefits (EOBs). The key is to correctly identify the insurer and policy number associated with that plan type.

    Locating Patient’s Medigap Card and Information

    Always request the patient’s most current Medigap insurance card. This card will typically contain:
  • The name of the Medigap insurance company (for Item 9A and 9D).
  • The policy number (for Item 9C).
  • Customer service contact information for verification.
  • If a physical card is unavailable, verify the information through the patient’s records or by contacting the patient directly. Never rely on outdated information.

    Verifying Medigap Coverage

    Before submitting a claim, it’s best practice to verify the patient’s Medigap coverage. This can be done by:
  • Calling the Medigap insurer: Use the number on the card or the insurer’s website.
  • Using online payer portals: Many Medigap insurers offer portals for providers to verify eligibility and benefits.
  • Checking the Medicare CWF: For claims that cross over automatically, Medicare’s CWF often holds the secondary payer information. However, always confirm with the patient or the Medigap insurer directly, as CWF data can sometimes be outdated.
  • Step-by-Step Guide to Filling Item 9A for Medigap Claims

    Let’s walk through the process of completing Item 9A and related fields when Medicare is the primary payer and Medigap is secondary.

    When Medicare is Primary and Medigap is Secondary

    This is the most common scenario for Medigap claims. Medicare processes the claim first, and then the Medigap plan pays the remaining approved out-of-pocket costs (deductibles, coinsurance, copayments) based on its coverage. 1. Item 1 (Type of Bill): Ensure “Medicare” is checked. 2. Item 1a (Insured’s ID Number): Enter the patient’s Medicare Beneficiary Identifier (MBI). 3. Item 4 (Insured’s Name): Enter the patient’s full name. 4. Item 9 (Other Insured’s Name): This is where Medigap information goes.
  • Item 9A: Enter the Medigap insurance company’s name (e.g., “UnitedHealthcare Medicare Supplement”).
  • Item 9B: Leave blank.
  • Item 9C: Enter the patient’s Medigap policy number (e.g., “UH123456789”).
  • Item 9D: Enter the full Medigap plan name (e.g., “UnitedHealthcare Medigap Plan G”).
  • 5. Item 11 (Insured’s Policy Group or FECA Number): Since Medicare is primary, this field is typically left blank. If there were another primary payer before Medicare (e.g., an employer group health plan), that information would go here, and Medigap would be tertiary. 6. Item 11d (Is there another health benefit plan?): Mark “YES” to indicate secondary coverage. 7. Item 13 (Insured’s or Authorized Person’s Signature): Enter “Signature on File” or “SOF” if you have a signed assignment of benefits from the patient. This authorizes the Medigap plan to pay the provider directly.

    Specific Data Entry for Each Sub-Field (9A, 9C, 9D)

    Imagine the CMS-1500 form in front of you.
  • Item 9A (Top Line): You’d type the Medigap insurer’s name, e.g., `AARP MEDICARE SUPPLEMENT`. Use uppercase for clarity.
  • Item 9C (Middle Line): You’d type the patient’s Medigap policy number, e.g., `1234567890`.
  • Item 9D (Bottom Line): You’d type the full Medigap plan name, e.g., `AARP MEDICARE SUPPLEMENT PLAN G`.
  • Simulated Screenshot Description: Visually, Item 9 on the CMS-1500 form is a large box, typically with three lines for text entry.
  • The first line, labeled “9A. OTHER INSURED’S POLICY OR GROUP NO.”, is where you’d see the Medigap company name.
  • The second line, labeled “9B. RESERVED FOR NUCC USE”, would be empty.
  • The third line, labeled “9C. OTHER INSURED’S DATE OF BIRTH”, is where you’d enter the Medigap policy number.
  • Directly below Item 9C, there’s a smaller box labeled “9D. INSURANCE PLAN NAME”, where the full Medigap plan name is entered.
  • The key is to ensure the Medigap company name is in 9A, the policy number in 9C, and the full plan name in 9D.

    Electronic Claim Submission (EDI) Implications for Medigap Data

    While the CMS-1500 form is for paper claims, the vast majority of Medicare claims and Medigap claims are submitted electronically via the ASC X12 837-P Health Care Claim Professional transaction. Understanding how Item 9A data translates to EDI is crucial for preventing billing errors.

    Mapping CMS-1500 to the 837-P Transaction

    The information from Item 9A, 9C, and 9D on the CMS-1500 form maps to specific loops and segments within the 837-P electronic claim file.
  • Loop 2320 (Other Subscriber Information): This loop is dedicated to secondary and tertiary insurance information.
  • SBR03 (Payer Responsibility Sequence Number Code): Indicates the payer’s responsibility (e.g., “P” for primary, “S” for secondary, “T” for tertiary). For Medigap, this would be “S”.
  • SBR04 (Individual Relationship Code): Indicates the relationship of the insured to the subscriber (e.g., “18” for self).
  • SBR05 (Insured Group or Policy Number): This is where the Medigap policy number from Item 9C is placed.
  • Loop 2000B (Subscriber Information): While this loop primarily contains primary subscriber data, information about the secondary payer’s name is often found in related segments.
  • NM101 (Entity Identifier Code): For the secondary payer, this would be “PR” (Payer).
  • NM102 (Entity Type Qualifier): “2” (Non-person entity).
  • NM103 (Payer Name): This is where the Medigap payer name from Item 9A and 9D is transmitted.
  • Loop 2330B (Other Payer Name): This loop provides detailed information about the secondary payer.
  • NM101 (Entity Identifier Code): “PR” (Payer).
  • NM103 (Payer Name): The Medigap insurance company name.
  • REFIG (Other Payer Policy Number): The Medigap policy number.

    Importance of Accurate Payer IDs and Policy Numbers in EDI

    For electronic claim submission, the Payer ID (also known as the EDI Receiver ID) is paramount. This unique identifier tells the clearinghouse and the payer’s system exactly where to route the electronic claim. While not directly on the CMS-1500 form in Item 9A, it’s a critical piece of information for EDI. Ensure your practice management system or billing software has the correct Payer ID for each Medigap insurer. Incorrect Payer IDs are a common cause of claim rejections and can lead to significant billing errors.

    State-Specific Medigap Regulations and Billing Nuances

    While Medigap plans are standardized by the federal government, state-specific regulations can introduce nuances that affect billing, particularly regarding enrollment and guaranteed issue rights.

    Guaranteed Issue Rights and Open Enrollment Periods

  • Open Enrollment: The best time for individuals to buy a Medigap policy is during their 6-month Medigap Open Enrollment Period, which starts the month they turn 65 and are enrolled in Medicare Part B. During this period, insurers cannot deny coverage or charge more due to health conditions.
  • Guaranteed Issue Rights: Outside of open enrollment, certain situations grant individuals “guaranteed issue rights,” meaning insurers must sell them a Medigap policy regardless of health. These situations include losing other coverage (e.g., Medicare Advantage plan leaves the area).
  • Billing Impact: While these regulations don’t change how* you fill Item 9A, they are crucial for understanding why a patient might have a Medigap plan, especially if they enrolled outside the standard open enrollment. It reinforces the need for thorough eligibility verification.

    State-Specific Medigap Plans (e.g., Massachusetts, Minnesota, Wisconsin)

    Most states follow the standardized Medigap plans (A-N). However, three states have their own standardized Medigap plans:
  • Massachusetts: Offers “Core” and “Supplement 1” plans.
  • Minnesota: Offers “Basic” and “Extended Basic” plans.
  • Wisconsin: Offers “Basic” plan and riders.
  • If your practice serves patients in these states, you must be aware of these unique plan names and ensure you enter them correctly in Item 9A and 9D. The policy numbers will still be unique to the insurer and plan. Always verify the exact plan name and policy number from the patient’s card.

    Impact on Claim Submission and Coordination of Benefits

    State-specific plans or regulations primarily impact the benefits covered and the enrollment process, not the fundamental mechanics of filling Item 9A. However, understanding these nuances helps in:
  • Accurate Expectation Setting: Knowing what a patient’s specific Medigap plan covers (whether federal or state-specific) helps predict the patient’s out-of-pocket costs and the expected payment from the Medigap insurer.
  • Effective Appeals: If a Medigap claim is denied, understanding the plan’s specific rules (which might be state-mandated) is vital for crafting a successful appeal process.
  • Real-World Billing Scenarios & Patient Status Changes

    Mastering Item 9A means being prepared for various patient scenarios. Here are common situations and how they impact Medigap billing errors.

    Scenario 1: Standard Medigap Claim

    Patient: Jane Doe, 72, has Medicare Part A & B and a Blue Cross Blue Shield Medigap Plan G. Service: Office visit, $150. Medicare approved amount is $100. Billing Action: 1. Medicare processes first: Medicare pays 80% of the approved amount ($80). 2. Remaining balance: $20 (20% coinsurance) is left. 3. CMS-1500 Item 9:
  • 9A: BLUE CROSS BLUE SHIELD MEDICARE SUPPLEMENT
  • 9C: BCBS123456789
  • 9D: BLUE CROSS BLUE SHIELD MEDIGAP PLAN G
  • 4. Item 11d: YES 5. Medigap processes: Blue Cross Blue Shield (Plan G) covers the $20 coinsurance. Outcome: Patient owes nothing for the coinsurance.

    Scenario 2: Patient with Multiple Secondary Payers (e.g., Employer Group Health Plan + Medigap)

    Patient: John Smith, 68, has Medicare Part A & B, an Employer Group Health Plan (EGHP) from his spouse’s work, and a Humana Medigap Plan F. Service: Diagnostic test, $500. Billing Action: 1. Coordination of Benefits (COB): Medicare is primary because John is over 65 and the EGHP is not from his current employer (it’s from his spouse). If it were his current employer, the EGHP might be primary. Always verify COB rules. 2. CMS-1500 Item 9 (EGHP as secondary):
  • 9A: Spouse’s EGHP Name (e.g., CIGNA HEALTHCARE)
  • 9C: Spouse’s EGHP Policy Number (e.g., CIGNA987654321)
  • 9D: CIGNA HEALTHCARE PPO
  • 3. CMS-1500 Item 11d: YES 4. Medicare processes first: Pays its portion. 5. EGHP processes second: Pays its portion of the remaining balance. 6. Medigap as tertiary: After the EGHP processes, any remaining Medicare-approved out-of-pocket costs (deductibles, coinsurance) would then be submitted to the Humana Medigap Plan F. This would require a separate claim submission to Humana, or the EGHP might forward it if they have a crossover agreement.
  • Important: For paper claims, you typically only list one secondary payer. If Medigap is tertiary, you would submit the claim to Medicare, then to the EGHP, and then manually submit the EOBs and claim to the Medigap plan. For EDI, the 837-P can handle multiple secondary/tertiary payers in Loop 2320.
  • Outcome: Complex COB, requiring careful tracking of EOBs and potentially multiple submissions.

    Scenario 3: Medigap Claim After Medicare Advantage Plan Disenrollment

    Patient: Mary Jones, 70, was in a Medicare Advantage (MA) plan but recently disenrolled and returned to Original Medicare, purchasing a new Medigap Plan N from Mutual of Omaha. Service: Follow-up visit, $120. Billing Action: 1. Verify effective dates: Ensure the MA plan termination date and the Original Medicare/Medigap effective dates are correctly recorded. Claims for services rendered before Medigap effective date will be denied. 2. CMS-1500 Item 9:
  • 9A: MUTUAL OF OMAHA MEDICARE SUPPLEMENT
  • 9C: MOO555444333
  • 9D: MUTUAL OF OMAHA MEDIGAP PLAN N
  • 3. Item 11d: YES Outcome: If dates are correct, Medicare processes, then Mutual of Omaha processes the remaining coinsurance (Plan N has a copay for office visits, so patient might owe a small amount).

    Scenario 4: Deceased Patient Medigap Claim

    Patient: Robert Green, 80, passed away, but services were rendered before his date of death. He had Medicare and a Cigna Medigap Plan G. Service: Hospital outpatient service, $800. Billing Action: 1. Medicare processes first: Medicare pays its portion. 2. CMS-1500 Item 9:
  • 9A: CIGNA MEDICARE SUPPLEMENT
  • 9C: CIGNA777888999
  • 9D: CIGNA MEDIGAP PLAN G
  • 3. Item 11d: YES 4. Item 2 (Patient’s Name): Enter “ROBERT GREEN (DECEASED)”. 5. Item 8 (Patient Status): Mark “Deceased”. 6. Medigap processes: Cigna will process the claim. Payment will typically be sent to the provider, or if the patient paid upfront, to the patient’s estate. Outcome: Claims for deceased patients require careful attention to detail, but Item 9A completion remains standard. —

    Common Denial Codes & Step-by-Step Appeal Instructions

    Even with meticulous attention to detail, Medig

    FAQ: Common Questions Answered

    What happens if I enter non-Medigap information in Item 9?

    Entering non-Medigap information in Item 9 (specifically 9A, 9B, or 9C) will disrupt the automated claims crossover process. Medicare’s system is designed to identify Medigap claims based on specific identifiers and formatting. If it doesn’t recognize the information as Medigap-related, the claim may be processed as a standard secondary claim, or more likely, rejected outright for incorrect payer identification. This prevents the claim from automatically forwarding to the Medigap insurer. Imagine trying to send a letter to a specific department, but you’ve addressed it to the wrong one entirely. It won’t reach its intended recipient, causing delays and confusion. Similarly, if you put non-Medigap details in Item 9, the system won’t know to send it to the Medigap insurer. This means your practice will face rejections, requiring manual intervention, resubmissions, and a significant slowdown in getting paid for the patient’s secondary coverage. It’s a direct hit to your cash flow and adds unnecessary work for your billing team.

    Why is the ‘Medigap,’ ‘Mgap,’ or ‘MG’ prefix so important?

    While not explicitly detailed in the provided text, these prefixes (e.g., ‘Medigap,’ ‘Mgap,’ or ‘MG’) are crucial identifiers often used in Item 9D (or sometimes within Item 9A, depending on payer specifics) to signal to the Medicare claims processing system that the claim is eligible for automatic crossover to a Medigap plan. When Medicare processes its portion and sees this prefix, it triggers the system to electronically forward the claim and the Explanation of Benefits (EOB) data directly to the identified Medigap insurer. Think of these prefixes as a special “fast pass” or a secret handshake for your claims. Without them, even if you’ve filled out the Medigap insurer’s name and policy number, Medicare’s system might not recognize it as a claim that should automatically “cross over.” This means instead of a smooth, automated transfer, your team might have to manually submit the claim to the Medigap insurer after Medicare pays, adding extra steps, increasing the chance of errors, and delaying your reimbursement. It’s about leveraging automation to keep your revenue cycle flowing efficiently.

    What are the primary consequences of incorrect Medigap claim submission?

    Incorrect Medigap claim submission, as highlighted in the article, directly leads to claim denials or rejections. This necessitates extensive rework, including claim correction, resubmission, and potentially appeals. Such errors inflate Accounts Receivable (AR) days, tie up staff resources in manual follow-up, and increase the risk of exceeding timely filing limits for the secondary payer, leading to lost revenue. When a Medigap claim is submitted incorrectly, it’s like hitting a roadblock in your revenue stream. Instead of a smooth payment, you get a denial notice, which means your billing team has to drop everything, investigate the error, correct it, and resubmit. This isn’t just extra work; it’s a significant delay in getting paid, which impacts your practice’s ability to cover operational costs. It can also frustrate patients who expect their secondary insurance to kick in seamlessly. Ultimately, it’s a drain on resources and a direct threat to your practice’s financial health.

    What if the Medigap policy has a different effective date than the service date?

    If the Medigap policy’s effective date does not encompass the date(s) of service being billed, the Medigap insurer will deny coverage for those specific services. Insurance coverage is always contingent on the policy being active and in force on the exact date a service was rendered. The claim will be processed based on the patient’s coverage status on the date of service, meaning if the Medigap policy wasn’t active, it won’t pay. Imagine you buy car insurance that starts on January 1st, but you have an accident on December 30th. Your new policy won’t cover it because it wasn’t active yet. It’s the same with Medigap. If a patient’s Medigap policy wasn’t active on the day they received care, that policy simply won’t pay for that specific service. This means your practice will either need to bill the patient directly for the remaining balance or explore other potential coverage options they might have had on that specific date. It’s a crucial detail that can easily lead to denials if not verified upfront.

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