What information is required in box 27 on CMS 1500?

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Box 27 on the CMS-1500 claim form requires the provider to indicate whether they accept assignment of benefits from the insurance payer.

Key Details for Box 27

  • Purpose: It shows whether the healthcare provider agrees to accept the payer's allowed amount as full payment for the rendered services.
  • Options: You must check or mark either YES or NO (only one option can be selected).
  • Meaning of "YES": The provider agrees to accept the insurance-approved payment amount directly, and the patient is only responsible for applicable coinsurance, copayments, and unmet deductibles.
  • Meaning of "NO": The provider does not accept assignment, meaning the insurance payment may go directly to the patient, and the patient might face higher out-of-pocket or balance-billing charges (depending on state and payer rules).
  • Requirements: Medicare and many commercial plans strictly require this field to be completed on every claim.

How to fill out a CMS-1500 form for Medicare?

You can submit professional medical claims using the CMS 1500 Claim Form Instructions Tool provided by Medicare administrative contractors.

📌 Patient and Insurance Information (Items 1–13)

  • Item 1 (Type of Payer): Select "Medicare".
  • Item 1a (Insured's ID): Enter the patient's Medicare Beneficiary Identifier (MBI).
  • Item 2 (Patient's Name): Enter last name, first name, and middle initial as shown on the Medicare card.
  • Item 3 (Birth Date & Sex): Enter the 8-digit birth date (MM/DD/YYYY) and mark the correct sex.
  • Item 12 & 13 (Signatures): Enter "Signature on File" or sign to authorize benefit release.

📊 Provider and Treatment Details (Items 14–33)

  • Item 21 (Diagnosis): Enter ICD-10 diagnosis codes (use indicator "0").
  • Item 24a–g (Service Lines): List the service dates, place of service code (e.g., 11 for office), CPT/HCPCS codes, charges, and units.
  • Item 24j (Rendering NPI): Enter the rendering provider's National Provider Identifier.
  • Item 33 (Billing Info): Enter the provider's name, address, phone number, and billing NPI.

What are the most common errors or mistakes made when filling out the CMS-1500 claim form and how can these be avoided?

The most common errors on the CMS-1500 claim form involve incorrect patient demographics, mismatched diagnostic and procedure codes, and missing provider identifiers, which can be avoided by using electronic claim scrubbers and verifying patient data at intake.

Common Errors and Mistakes

  • Mismatched Patient or Insured Information (Boxes 1–13): Entering the subscriber's date of birth instead of the dependent patient's, or submitting incorrect policy numbers and misspelled names.
  • Inaccurate or Unspecific ICD-10 Codes (Box 21): Failing to code to the highest level of specificity or using vague/unspecified diagnosis codes that fail to support medical necessity.
  • CPT/HCPCS and Diagnosis Pointer Errors (Boxes 24D & 24E): Using incorrect procedure codes, misusing modifiers, or failing to link the correct diagnosis pointer to the corresponding service line.
  • Incorrect Provider Identifiers (Boxes 24J & 33a): Mixing up the billing provider, rendering provider NPI (National Provider Identifier), or entering an incorrect Tax ID.
  • Omitted Prior Authorizations or Resubmission Data (Boxes 23 & 22): Leaving out prior authorization numbers when required, or failing to include the original reference number and correct resubmission code on corrected claims.
  • Using Outdated or Improperly Formatted Paper Forms: Utilizing an obsolete version of the form or hand-writing entries instead of typing clean data meant for optical character recognition (OCR) scanners.

How to Avoid Them

  • Automate Validation: Run claims through electronic practice management software or a Medical Billing Clearinghouse to catch formatting or coding errors before final submission.
  • Update Demographics Regularly: Re-verify patient insurance and personal information at every visit or at least twice a year to prevent front-end rejections.
  • Check Code Specificity: Review full CPT and ICD-10 code descriptions rather than relying on short labels or memory.
  • Establish Pre-Submission Checklists: Audit a sample of claims monthly to track recurring error trends and retrain billing staff accordingly.

What information should be included in the CMS-1500 boxes in medical billing?

The CMS-1500 Claim Form has 33 numbered boxes divided into two main sections: patient/insured information (Boxes 1–13) and physician/supplier information (Boxes 14–33).

Patient and Insured Information (Boxes 1–13)

  • Boxes 1–7: Captures the type of insurance plan, insured ID, patient demographics (name, birth date, sex, address), insured's name/address, and the patient's relationship to the insured.
  • Boxes 8–13: Includes reserved fields, secondary insurance details (9–9d), accident indicators (10a–10c), primary policy numbers (11), and authorized signatures/signatures on file (12 & 13).

Physician or Supplier Information (Boxes 14–33)

  • Boxes 14–23: Details dates of illness, work restrictions, referring provider info, outside lab charges, ICD-10 diagnosis codes, and prior authorization numbers.
  • Boxes 24–33: Outlines the core service lines (CPT/HCPCS codes, modifiers, charges, dates), financial totals and tax ID info, service facility location, and billing provider details including NPI and taxonomy.

Which information is entered in the CMS-1500 block?

The CMS-1500 Claim Form requires specific patient, insurance, and provider data across its 33 numbered blocks.

Key CMS-1500 Blocks and Their Information

  • Block 1 & 1a: Type of health insurance coverage (Medicare, Medicaid, Private) and the insured's ID number.
  • Block 2: Patient's full name (last, first, middle initial).
  • Block 3: Patient's birth date (MM/DD/YYYY) and sex.
  • Block 4: Insured's name (if different from the patient).
  • Block 5: Patient's address and telephone number.
  • Block 9–9d: Other insured's name, policy/group number, and supplemental plan information (if secondary insurance exists).
  • Block 14: Date of current illness, injury, or pregnancy (LMP).
  • Block 17: Name of the referring provider or other source.
  • Block 21: Diagnosis codes (up to 12 ICD-10 codes) explaining medical necessity.
  • Block 24A–24J: Details of specific services, including dates of service, CPT/HCPCS procedure codes, charges, days/units, and rendering provider NPI.
  • Block 25: Federal Tax ID number (EIN) or Social Security Number (SSN) of the provider/supplier.
  • Block 31: Provider signature and date.
  • Block 33: Billing provider's name, address, phone number, and NPI.

CMS 1500 claim form Box 27, Accept Assignment, Description/Details/Explanation

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What could cause a CMS 1500 claim form to be rejected?

A CMS-1500 claim form is typically rejected during initial validation checks due to data entry errors, missing information, or mismatched demographic records.

Common Causes of Rejection

  • Patient and Insured Mismatches (Boxes 1–13): Misspelled names, wrong dates of birth, incorrect member IDs, or transposed digits cause automatic rejections when electronic systems check eligibility files.
  • Incorrect Provider Identifiers (Boxes 24J, 33a): Missing or invalid National Provider Identifier (NPI) numbers or incorrect federal Tax ID numbers (Box 25) trigger entity code rejections.
  • Coding and Diagnosis Errors (Boxes 21, 24D, 24E): Using outdated CPT, HCPCS, or ICD-10 codes, or failing to include a valid diagnosis pointer in Box 24E, will stop a claim from processing.
  • Missing Authorizations or Referrals (Boxes 17, 23): Forgetting to add prior authorization numbers (Box 23) or omitting the referring provider's name and NPI (Box 17) results in immediate rejection by managed care plans.
  • Outdated Form Version (Box): Submitting data on an old, non-approved version of the CMS-1500 form instead of the current NUCC-approved standard will fail intake checks.
  • Signature and Format Issues (Boxes 27, 31, 33): Leaving signature fields blank, using a digital stamp instead of an accepted signature, or using improper print alignment on paper submissions causes rejection before adjudication.

Can you fill out CMS 1500 by hand?

You should not fill out the CMS 1500 form by hand.

Why Handwriting Is Not Allowed

  • Scanner Rejections: Insurance companies use Optical Character Recognition (OCR) machines to read claims. These scanners cannot read messy or handwritten text well.
  • Processing Delays: Handwritten forms often cause errors. This leads to claim denials or slow payments.
  • Payer Rules: Most insurance payers and Medicare require typed, computer-printed, or electronic submissions (837P formats).

Best Practices for Paper Submissions

  • Use a Printer: Print forms using a laser or inkjet printer with true black ink.
  • Use Correct Fonts: Type in all uppercase letters using standard fonts like Courier New or Times New Roman.
  • Use Original Paper: Always print on the official red-and-white CMS 1500 (02/12) scannable form. Photocopies or black-and-white copies are rejected.

What are two most common claim submission errors?

The two most common claim submission errors in medical billing are incorrect patient/insurance information and medical coding errors.

1. Incorrect Patient or Insurance Information

  • Typographical errors: Misspelled names or wrong digits in a date of birth.
  • Wrong identification: Invalid member ID or incorrect insurance policy number.
  • Outdated details: Expired or inactive insurance coverage details.

2. Medical Coding Errors

  • Wrong codes: Incorrect CPT (Current Procedural Terminology) or ICD-10 diagnosis codes.
  • Missing details: Omitted or incorrect billing modifiers.
  • Mismatches: Diagnosis and procedure codes that do not match or fail to support medical necessity.

You can learn more about preventing these issues through professional guidance from The Medicator's.

What are the questions and answers for the CMS 1500 claim form?

Test your knowledge of medical billing and coding with this interactive quiz covering the CMS-1500 claim form, its fields, rules, and core guidelines.

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CMS-1500 Claim Form Practice Quiz

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1.

What is the primary purpose of the CMS-1500 claim form in medical billing and coding?

A.
To submit inpatient hospital services and facility claims to insurance payers.

Incorrect. Inpatient and institutional hospital claims are submitted using the UB-04 (CMS-1450) form, not the CMS-1500.

B.
To submit outpatient and professional services claims by physicians and suppliers.

Correct! The CMS-1500 is the standard paper/electronic claim form used by non-institutional providers and suppliers for outpatient services.

C.
To request prior authorization from an insurance company before performing a medical procedure.

Incorrect. Prior authorization is handled through pre-approval requests, not by submitting a finalized claim form.

D.
To bill patients directly for out-of-pocket expenses and copays after an encounter.

Incorrect. This form is sent to third-party insurance payers or clearinghouses, not as a direct patient billing statement.

Think about the type of setting (outpatient office vs. inpatient hospital) where a doctor provides professional services.

2.

Which version of the CMS-1500 paper claim form is currently accepted by major insurance carriers and accommodates ICD-10 codes?

A.
08/05

Incorrect. The 08/05 version is an older iteration that predates the mandatory transition to ICD-10.

B.
12/08

Incorrect. This is an incorrect sequence for the version date.

C.
02/12

Correct! The 02/12 version was designed to handle the transition to ICD-10-CM diagnosis codes and updated provider indicators.

D.
01/20

Incorrect. There is no widely recognized 01/20 version of the CMS-1500 claim form.

Recall the month and two-digit year stamp found in the bottom-right corner of the current standard form, implemented right around the time ICD-10 adoption was being finalized.

3.

In Block 1 of the CMS-1500 claim form, what does checking the box labeled "OTHER" typically designate?

A.
Black-lung, state-sponsored, or specific health benefit plans not explicitly listed in the main options.

Correct! Block 1 lists major categories like Medicare, Medicaid, and TRICARE, while "OTHER" covers programs like Black Lung or specific state assistance programs.

B.
Commercial health insurance or private employer-sponsored plans.

Incorrect. Commercial and private insurances are covered under the "FECA Blk Lung" or specific commercial selections rather than the general "OTHER" checkbox.

C.
Secondary Medicare coverage.

Incorrect. Secondary coverage details are handled via coordination of benefits blocks (such as Block 9), not Block 1.

D.
Medicaid spend-down programs.

Incorrect. Medicaid has its own dedicated checkbox in Block 1.

Consider specialized or niche government-regulated health benefit programs that do not fall under standard Medicare, Medicaid, or commercial insurance.

4.

What specific piece of information must be entered into Block 1a of the CMS-1500 form?

A.
The patient's social security number.

Incorrect. The patient's SSN is not the required identifier for Block 1a.

B.
The physician's National Provider Identifier (NPI).

Incorrect. Provider NPIs belong in dedicated provider blocks, such as Block 24J or 33b.

C.
The patient's date of birth in MMDDYYYY format.

Incorrect. Date of birth belongs in Block 3.

D.
The insured's identification number.

Correct! Block 1a captures the unique ID number assigned to the primary insured policyholder by the insurance plan.

Block 1a is closely linked to the insurance policyholder's identification card number, right above the patient's personal details.

5.

On the 02/12 version of the CMS-1500 form, how many maximum diagnosis codes can be reported in Block 21?

A.
4

Incorrect. Four diagnosis codes were the limit on older versions of the form prior to the 02/12 update.

B.
12

Correct! Block 21 accommodates up to 12 diagnosis codes, designated alphabetically from A through L.

C.
8

Incorrect. The form allows more than eight diagnosis codes.

D.
24

Incorrect. 24 exceeds the maximum capacity of Block 21.

Think of the number of letters in the alphabet used to label the diagnosis pointers in Block 21 (A through L).

6.

What is the function of the "Diagnosis Pointer" located in Block 24E of the CMS-1500 form?

A.
It indicates the primary billing provider's specialty code.

Incorrect. Provider specialty codes are designated elsewhere, not via diagnosis pointers.

B.
It acts as a sequence number for the order in which services were performed.

Incorrect. Chronological sequence of service is denoted by dates of service in Block 24A.

C.
It links the specific procedure code in Block 24D to the corresponding diagnosis letter from Block 21.

Correct! Block 24E maps the procedure code to the letter (A-L) in Block 21 that justifies the medical necessity for that specific service.

D.
It identifies whether the procedure requires a prior authorization number.

Incorrect. Prior authorization numbers are reported in Block 23.

This field connects the "why" (diagnosis) to the "what" (procedure) on each specific line item of service.

7.

Where should the National Provider Identifier (NPI) of the specific rendering provider be placed on the 02/12 CMS-1500 form if it differs from the billing provider?

A.
In the shaded area of Block 24J.

Correct! The rendering provider’s NPI is entered in the shaded portion of line 24J when the rendering provider is different from the group/billing provider in Block 33a.

B.
In Block 1a.

Incorrect. Block 1a is reserved for the insured's policy ID number.

C.
In Block 25.

Incorrect. Block 25 contains the Federal Tax ID (EIN or SSN).

D.
In Block 21.

Incorrect. Block 21 is exclusively for ICD-10-CM diagnosis codes.

Look into the detail rows (Blocks 24) where individual procedures are listed along with service dates and modifiers.

8.

Blocks 10a through 10d on the CMS-1500 form are used to capture what type of clinical context?

A.
Secondary commercial insurance coverage details.

Incorrect. Secondary insurance information belongs in Block 9.

B.
EPSDT screening tracking and referral codes.

Incorrect. EPSDT details have separate designated spots or conditional instructions rather than Blocks 10a-10d.

C.
Patient authorization signatures and release of information dates.

Incorrect. Signatures and information releases are captured in Blocks 12 and 13.

D.
Whether the patient's condition is related to employment, auto accidents, or other accidents.

Correct! Blocks 10a-10d ask "Is patient's condition related to..." to identify workers' compensation, auto liability, or other accident claims.

These boxes require "YES" or "NO" answers regarding external liability or work-related injury origins.

9.

Which block on the CMS-1500 form is designated to report the Date of Current Illness, Injury, or Pregnancy (LMP)?

A.
Block 11

Incorrect. Block 11 is used for insured's policy group or policyholder details.

B.
Block 14

Correct! Block 14 captures the date of the onset of illness, accident, or last menstrual period.

C.
Block 19

Incorrect. Block 19 is used for additional supplemental or miscellaneous claim information/remarks.

D.
Block 24A

Incorrect. Block 24A captures the specific dates of service for each procedure line, not the initial date of injury or illness onset.

It sits just above the patient relationship and condition blocks, prior to the hospital/laboratory outside purchase sections.

10.

If a patient has a secondary insurance plan, which section of the CMS-1500 form is used to record the other insured's name and policy details?

A.
Blocks 2 through 7

Incorrect. Blocks 2 through 7 pertain to the primary patient and primary subscriber demographics.

B.
Blocks 32a through 33b

Incorrect. Blocks 32 and 33 report service facility and billing provider/supplier information.

C.
Blocks 9, 9a, 9b, 9c, and 9d

Correct! The Block 9 series is dedicated to "Other Insured's Name" and policy data for coordination of benefits when secondary or tertiary coverage exists.

D.
Blocks 10a through 10d

Incorrect. Blocks 10a-10d check for accident/employment relations.

Look right below the primary insured's subscriber block (Block 11) for the corresponding secondary reference fields.

11.

What information must be recorded in Block 24D of the CMS-1500 form?

A.
CPT or HCPCS procedure codes and any required modifiers.

Correct! Block 24D lists the procedure codes and appropriate modifiers that describe the services provided to the patient.

B.
The total charges for each individual line item.

Incorrect. Line item charges are reported in Block 24F.

C.
The number of days or units of service delivered.

Incorrect. Days or units are entered in Block 24G.

D.
The place of service code.

Incorrect. Place of service is recorded in Block 24B.

This is the central column in the 24 series where the 5-digit CPT code or HCPCS code resides alongside modifier additions.

12.

What identifier is required to be reported by the billing provider in Block 25 of the CMS-1500 claim form?

A.
State license number

Incorrect. State license numbers may be needed in specialized or local boxes (like Block 31 or 19), but not Block 25.

B.
National Provider Identifier (NPI)

Incorrect. NPI goes in designated blocks like 33a or 24J.

C.
Commercial provider enrollment number (UPIN/PIN)

Incorrect. UPIN/PIN systems are obsolete and replaced by NPI and Tax ID tracking.

D.
Federal Tax ID (Employer Identification Number [EIN] or Social Security Number [SSN])

Correct! Block 25 captures the provider's or organization's IRS tax identification number and indicates whether it is an EIN or SSN.

Think about tax reporting and financial tracking for the entity sending the medical bill.

13.

What information is required in Block 33 and 33a of the CMS-1500 claim form?

A.
The patient’s emergency contact details and physical residential address.

Incorrect. Patient address details are logged near the top in Block 5.

B.
The billing provider's name, address, telephone number, and NPI number (in 33a).

Correct! Block 33 outlines the billing provider's contact details, and Block 33a specifically requires the billing provider's NPI.

C.
The outside laboratory name and facility charges.

Incorrect. Outside laboratory information is reported in Block 20.

D.
The primary insurance clearinghouse identifier.

Incorrect. Clearinghouse IDs are electronic routing details, not physical provider blocks on the printed form.

This is located at the very bottom right of the form, identifying who is requesting payment and where payment or correspondence should go.

14.

Which block on the CMS-1500 claim form displays the total submitted charges for all services listed on the form?

A.
Block 24F

Incorrect. Block 24F lists the charges for each individual line-item service row, not the grand total.

B.
Block 29

Incorrect. Block 29 reports the amount paid by the patient or prior payers (amount paid), not the total submitted charge.

C.
Block 28

Correct! Block 28 totals the sum of all individual line charges found in column 24F.

D.
Block 30

Incorrect. Block 30 is typically used for balance due calculations or specific balance tracking (e.g., balance due in some formats).

It sits just under the line-item grid, right above the balance/payment blocks (Block 29 and 30).

15.

What does marking "YES" in Block 27 (Accept Assignment) signify on the CMS-1500 form?

A.
The provider agrees to accept the insurance-allowed amount as full payment, minus any applicable deductible/copay.

Correct! Accepting assignment means the provider cannot balance-bill the patient for amounts exceeding the insurer's approved amount.

B.
The patient authorizes the insurance company to pay the physician directly.

Incorrect. Patient authorization to pay the provider is handled by the signature in Block 13.

C.
The insurance carrier waives all prior authorization requirements for the visit.

Incorrect. Acceptance of assignment is a financial agreement regarding fees, not a waiver of prior authorization.

D.
The provider guarantees that the service will be fully covered at 100%.

Incorrect. It does not guarantee full payment or coverage percentages, only agreement to the contracted/allowed amount structure.

Think about contractual obligations regarding fees and whether a doctor can balance bill a patient over the insurer's approved fee schedule.

What are common reasons for claim rejections?

Common reasons for claim rejections and denials include clerical errors, missing data, and unverified coverage rules.

Administrative and Clerical Errors

  • Incorrect patient details: Typos in names, wrong birth dates, or invalid insurance policy numbers.
  • Coding mistakes: Mismatched diagnostic or procedure codes (such as CPT or ICD-10 errors).
  • Missing information: Left-blank fields, missing provider signatures, or incomplete medical records.
  • Timely filing violations: Submitting the paperwork past the insurance provider's strict deadline.

Coverage and Policy Issues

  • Lack of prior authorization: Receiving treatments or tests before securing required pre-approval from the insurer.
  • Not medically necessary: The payer deciding the specific care or medication does not meet their clinical criteria.
  • Out-of-network services: Using a provider outside your plan's approved network without an exception.
  • Service exclusions: Requesting care that falls completely outside the scope of your specific insurance policy.