How to fill out CMS-1500, line by line
CMS-1500 is a professional health-insurance claim form. For a Medicare claim, first determine whether another insurer is primary to Medicare. Then connect the patient and coverage details to the services, charges, and provider certification. These instructions explain the supplied Medicare rules for the NUCC 02/12 form; they are not universal rules for every health plan shown in item 1.
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How CMS-1500 works for a Medicare claim
CMS-1500 is the prescribed form for claims prepared and submitted by physicians or suppliers, whether the claim is assigned or unassigned. It is not ordinarily the form a beneficiary uses to submit a personal Part B claim. In the circumstances described in the supplied manual, a beneficiary or representative uses Form CMS-1490S instead, along with an itemized bill.
Important scope boundary
Use this page for the supplied Medicare completion rules. The CMS-1500 serves multiple health insurers, and the form directs users to the separate instructions issued by the applicable program.
Before starting, gather the applicable coverage information, the patient Medicare card, service and diagnosis records, procedure information, charges, facility details when applicable, and required authorizations. The supplied Medicare instructions require 8-digit dates in all date fields. Complete the coverage route before treating the rest of the form as a routine sequence of boxes: that decision controls which insured and payer fields apply.
Choose the insurance route before filling the patient fields
The patient-and-insured half of the claim is organized by payer order, not merely by the printed order of boxes. In item 1, check the coverage applicable to the claim. For Medicare, item 1a requires the patient’s HICN whether Medicare is primary or secondary under the supplied instructions. Enter the patient’s name in item 2 as shown on the Medicare card, then enter the 8-digit birth date and sex in item 3. Item 5 holds the patient’s mailing address and telephone number.
Which Medicare coverage route applies?
Determine payer order
other coverage is primary → 2
no primary insurer → 3
Other insurer is primary
complete related fields → 4
No insurer is primary
enter NONE in item 11 → 6
Items 4, 6, 7, and 11–11c
paper secondary-payer claim → 5
then continue → 6
Primary payer EOB
Item 12 authorization
When another insurer is primary to Medicare
Item 11 is required because completing it acknowledges a good-faith effort to determine whether Medicare is primary or secondary. If another insurer is primary, enter the insured’s policy or group number in item 11 and complete items 11a–11c. Complete items 4, 6, and 7 as well: item 4 names the insured, item 6 identifies the patient’s relationship to that insured, and item 7 gives the insured’s address and telephone number. If the patient and insured are the same, use SAME where the instructions direct it. For a paper claim considered for Medicare secondary-payer benefits, send the primary payer’s explanation of benefits (EOB) with the claim.
If no insurance is primary to Medicare, enter NONE in item 11 and proceed to item 12.
In items 10a–10c, answer yes or no for employment, auto-liability, or other-accident involvement. A YES may indicate that other insurance is primary, so identify that coverage in item 11.
Item 10d is exclusively for Medicaid information. When applicable, enter the patient’s Medicaid number preceded by MCD. Item 11d is blank for Medicare.
When the claim uses a mandated Medigap transfer
Item 9 is not a general place to list every supplemental policy. Under the supplied Medicare instructions, participating physicians or suppliers complete items 9–9d only when the beneficiary asks to assign Medigap benefits to that participating provider or supplier. Medigap is a private Medicare supplemental policy. This route supplies the information Medicare needs to forward claim information to the Medigap insurer. If that trigger does not apply, leave item 9 blank rather than entering other supplemental coverage there.
For an applicable transfer, enter the Medigap insured’s name in item 9, or SAME if it matches item 2. Item 9a uses the policy or group number with the required MEDIGAP, MG, or MGAP prefix; completing 9a also requires 9d. Enter the insured’s birth date and sex in 9b. Leave 9c blank when a Medigap payer ID is entered in 9d; otherwise use the abbreviated claims-processing address from the Medigap identification card. In 9d, enter the 9-digit payer ID or, if none exists, the plan name. Item 13 is the related authorization for payment of mandated Medigap benefits. Item 12 separately authorizes release of information needed to process the claim and, when assignment is accepted, payment to the provider or supplier. The supplied instructions permit Signature on File or a computer-generated signature in the stated circumstances.
Complete the provider and claim-detail fields
Items 14–23 are not one routine chronology. They document specific circumstances that support the services being billed, so use the trigger for each field rather than filling every visible box. Item 14 is the 8-digit date of current illness, injury, or pregnancy. For chiropractic services, the supplied instructions instead use item 14 for the date the course of treatment began. Leave item 15 blank for Medicare. Use item 16 only when an employed patient is unable to work in the current occupation.
Dates, referrals, and service circumstances: items 14–20
In items 17 and 17a, report the ordering or referring physician and the associated identifier when a physician ordered or referred the service or item. A claim involving multiple ordering or referring physicians requires a separate CMS-1500 for each physician.
Item 18 records a related hospitalization date when the current service followed or resulted from that hospitalization.
Use item 20 for diagnostic tests subject to purchase-price limitations. A YES means another entity performed the test; enter the purchase price under charges and complete item 32. Bill multiple purchased diagnostic tests on separate claim forms.
Do not treat item 19 as a general notes field
Item 19 has several profession-specific uses. If an unlisted procedure or not-otherwise-classified code needs a narrative, put a concise description in item 19 if it fits; otherwise submit an attachment. For other specialized item 19 uses, consult HHS Medicare Claims Processing Manual, Chapter 26, §10.4, Item 19. Item 19 can hold up to three conditions; additional conditions require a separate CMS-1500.
Diagnosis and authorization information: items 21–23
Item 21 lists the patient’s diagnoses or conditions in priority order. It becomes an input for the service lines: item 24e uses one reference number from item 21 to connect each service to its primary diagnosis. Leave item 22 blank for Medicare. Item 23 holds one applicable prior-authorization or other specified identifier under the supplied rules. If more than one condition is needed in item 23, use a separate CMS-1500 rather than combining multiple conditions in that field.
Report each service line, then total the claim
Item 24 is the claim’s core repeating record. Each line should show what was provided, when and where it was provided, the procedure or supply, the diagnosis reference supporting that line, the charge, and the days or units. Complete the line before calculating the claim total. This keeps the two key relationships clear: item 21 supplies the diagnosis reference used in item 24e, and every amount in item 24f contributes to item 28.
The service-line flow: item 24A–24J
Enter the 8-digit service date in item 24a. For a series of identical services, use from/to dates and report the number of days or units in 24g. A service spanning more than one day needs a valid to-date.
Enter the appropriate place-of-service (POS) code in 24b. The code identifies where the service or item was furnished; use the official POS code list for code selection rather than treating this guide as a full code catalog.
Enter the HCPCS procedure, service, or supply code and applicable modifiers in 24d. An unlisted or NOC code needs the item 19 narrative or an attachment.
In 24e, enter one diagnosis reference number from item 21 for that service line. In 24f, enter that line’s charge. In 24g, enter actual days or units; enter 1 when one service was performed. For anesthesia, convert elapsed time to total minutes and enter the minutes in 24g.
Under these Medicare instructions, leave 24c, 24h, 24i, and 24j blank.
A flow showing that one diagnosis reference from item 21 is used in item 24e and that all item 24f charges are added for item 28.
Totals, payment, and assignment: items 25–30
Item 25 is the provider or supplier federal tax ID. Item 26 is optional and may hold the account number from the provider or supplier’s accounting system. In item 27, indicate whether the provider or supplier accepts assignment of Medicare benefits. The earlier Medigap-transfer route has an added consequence: when item 9 indicates Medigap and item 13 authorizes payment, the provider or supplier must be participating and accept Medicare assignment for all covered charges for all patients.
Items 28 and 29 use different inputs.
Field | Enter | Do not substitute |
|---|---|---|
28 — Total charge | The sum of every service-line charge in item 24f. | Patient payment for the charge total. |
29 — Amount paid | Only the total the patient paid on covered services. | All billed charges or payments for noncovered services.30 |
30 | Leave blank for Medicare. | A balance or calculated remainder. |
Finish the certification, facility, and billing provider fields
Item 31 is the provider/supplier or representative certification signature and signing date. The claim may be processed under the supplied conditions when the signature is on file, an authorization is attached, or the field uses Signature on File or a computer-generated signature. This certification closes the claim; it does not replace the patient authorization in item 12 or the conditional Medigap authorization in item 13.
Item 32 identifies where the service occurred when it was furnished in a hospital, clinic, laboratory, or another facility instead of the patient’s home or physician’s office. It is also required when item 20 shows a purchased diagnostic test; in that situation, report the supplier information specified by the instructions. Item 33 is separate: it identifies the billing provider or supplier with the required name, address, ZIP code, and telephone number. The service location and the billing entity can be different facts, which is why the form has both fields.
The coverage route agrees with items 4–11, the EOB is included when required for a paper Medicare secondary-payer claim, and item 9 is used only for the defined Medigap-transfer route.
Every item 24e diagnosis pointer exists in item 21, and item 28 equals the sum of all item 24f charges.
The required certifications and billing-provider information are complete, and item 32 is completed when the facility condition applies.
Do not treat item 8, item 22, item 30, or Medicare-not-required service-line fields as routine entries under these supplied instructions.
Common CMS-1500 follow-ups
Is CMS-1500 the same as a beneficiary’s request for Medicare payment?
No. CMS-1500 is the provider/supplier claim form in the supplied Medicare manual. In the specified situations where a beneficiary or representative files a Part B claim personally, the manual identifies Form CMS-1490S, with an itemized bill, as the beneficiary form.
What does “unprocessable” mean?
It means the claim cannot be processed and must be corrected or resubmitted through the applicable notification process. It does not necessarily mean that the physical paper claim is mailed back.
If you need a fictional filled-form visual, use the dedicated CMS-1500 example page rather than treating a sample as a substitute for the applicable coverage route and official Medicare field rules. For a different form task, browse other government form instructions.
Sources and how this page was made
This guide explains the official sources listed below in plain language. Displayed amounts, limits, percentages, and timing rules come from that material.