Billing and claims
Medicaid ID Number Format by State: How to Check a Rider's Number Before You Bill
Overview
A Medicaid ID number format is the length and pattern a state uses for its members' ID numbers, such as Illinois's 9-digit recipient number or Indiana's 12-digit member ID. Billers check each rider's number against that pattern and the state's eligibility system before billing, because a wrong or mistyped ID gets the claim rejected or denied.
- Formats differ by state. Illinois uses 9 digits, Indiana 12, Alabama 13, and Arizona a letter followed by 8 digits.
- The ID goes in box 1a of the CMS-1500 and loop 2010BA of the 837P, exactly as the payer issued it.
- Bill the ID of the payer you send the claim to. A health plan can issue its own member ID.
- A bad ID can come back as reason code 31 or 140, or remark code N382, or as a rejection before processing.
- A member ID is a health plan beneficiary number under HIPAA, so treat it as protected health information.
What the Medicaid ID number is
Each state Medicaid program gives every member an ID number and prints it on a card. The card has a different name in each state: the Common Benefit ID Card in New York, the MediPlan Card in Illinois, the Benefits Identification Card in California, the mihealth card in Michigan, and the services card in Washington. The number is what ties a ride to the rider’s coverage on your claim.
The card is not proof of coverage. Medi-Cal’s manual says a card is permanent and stays with the member even in months without coverage, and Michigan’s manual (version October 1, 2026) says its card does not guarantee eligibility. Check coverage for the ride date in the state’s system. See eligibility verification and MMIS.
The number goes in two places, depending on how you bill:
- Paper. Box 1a of the CMS-1500. The NUCC manual (version 13.0, July 2025) says to enter the ID as shown on the card for the payer you are billing, and the box holds up to 29 characters.
- Electronic. Loop 2010BA of the 837P, element NM109, with the qualifier MI for member identification number. Indiana, Arizona, and Utah all ask for MI there.
Medicaid ID formats by state
Of the 11 states below, seven use digits only, from 9 to 13 of them. New York, Arizona, and Washington add letters, and California’s card ID runs 14 characters. Here is each format as the state’s own claims guide or manual gives it, with the guide’s date.
| State and guide date | What the number is called | Format |
|---|---|---|
| New York (July 2026) | Medicaid ID on the Common Benefit ID Card | 8 characters: 2 letters, 5 digits, 1 letter |
| Texas (September 2026) | Medicaid number | 9 digits, starting with 1 through 7. MTP claims use the 10-digit MPCN |
| Illinois (November 2021) | Recipient number on the MediPlan or All Kids card | 9 digits |
| Indiana (November 2024) | IHCP Member ID | 12 digits |
| Arizona (November 2022) | AHCCCS Member ID | 1 letter and 8 digits, such as A12345678 |
| California (April 2025) | Benefits Identification Card ID | 14 characters |
| Utah (July 2024) | Beneficiary ID | 10 digits |
| South Dakota (September 2026) | Recipient ID | 9 digits, without the 3-digit generation number |
| Alabama (July 2026) | Medicaid number | 13 digits, starting with 5 |
| Michigan (October 2026) | Beneficiary ID from the state’s eligibility check | 10 digits |
| Washington (September 2025) | ProviderOne client ID | 9 digits followed by WA |
A few rules sit behind those rows:
- Texas wants the complete nine-digit number on every claim. Valid Medicaid numbers start with 1 through 7, and numbers starting with 9 belong to its program for children with special health care needs, not Medicaid. The fee-for-service Medical Transportation Program prints a 10-digit MPCN on its authorization form, and MTP claims put that MPCN in box 1a. See Texas.
- California’s Eligibility Confirmation Letter shows the member’s Client Identification Number (CIN) instead of the card ID, and Medi-Cal’s claim instructions (February 2025) say to enter the number as it appears on the card or letter you were given. See California.
- Alabama has denied claims with its old numbers, the ones beginning with 000, since January 17, 2011.
- Michigan says to bill with the 10-digit beneficiary ID that its CHAMPS eligibility inquiry returns. See Michigan.
How to check a rider’s ID before you bill
- Copy it from the source. Take the number from the card or the eligibility response, not from a booking note. When Medi-Cal’s eligibility system says the current card ID and issue date are required, use the newest ones, or the claim is denied.
- Check the length and pattern. Compare it with the table. A 9-digit number for an Indiana rider, or an Alabama number that does not start with 5, is wrong before you send it.
- Match the name and birth date exactly. Texas says the name, date of birth, sex, and nine-digit number must exactly match its eligibility record. Illinois wants the name exactly as it appears on the card, and South Dakota says no nicknames.
- Leave off extra numbers. South Dakota’s 3-digit generation number is not part of the ID and does not go on a claim.
- Use the right payer’s number. For a health plan claim, use the member ID the plan issued, if it issued one. The NUCC rule for box 1a is the ID for the payer you are billing.
- Check coverage for the ride date. Run the eligibility check before the ride and again before you bill a standing order.
Broker trips: the trip ID and the member ID
A broker gives each ride its own trip ID, and that number is not the Medicaid ID. Louisiana’s NEMT rules (section 10.5, issued July 14, 2025) have the broker collect a daily trip log from each provider with both the trip ID and the rider’s name, Medicaid ID number, address, and signature, and check every claim against that log before paying. MTM Health’s Rhode Island handbook (last updated July 1, 2026) has you claim each ride by its trip ID.
Keep both numbers on every trip record. The trip ID gets the broker claim paid, and the Medicaid ID lets you check coverage and answer an audit. See how to bill NEMT brokers.
What a wrong ID does to the claim
A wrong or mistyped ID stops payment. Texas lists a mismatch between the rider’s details and its eligibility file first among the most common reasons electronic professional claims are rejected (September 2026). Depending on where the payer catches it, the claim comes back with one of these codes:
- Claim status code 30 or 33 on a claim acknowledgment: the subscriber and ID do not match, or were not found. If it comes with a rejection, fix the ID and send a new claim.
- Reason code 31 on a remittance: the patient cannot be identified as the payer’s insured.
- Reason code 140: the patient’s ID number and name do not match.
- Remark code N382: the patient identifier is missing, incomplete, or invalid.
See claim adjustment reason codes for the rest of the codes, and claim rejection vs denial for how to fix each kind. For a claim sent to the wrong payer altogether, see payer ID.
Keep member IDs private
A Medicaid ID is a health plan beneficiary number, one of the identifiers HIPAA lists in 45 CFR 164.514(b)(2) that make health information identifiable. When HIPAA applies to you, trip records that carry it are protected health information under 45 CFR 160.103. Share it only with staff and partners who need it to run or bill the ride, and keep it out of group texts and open spreadsheets. See protected health information and HIPAA for NEMT providers.
Frequently asked questions
How many digits is a Medicaid ID number?
It depends on the state. As of October 2026, Illinois, Texas, and South Dakota use 9 digits, Utah and Michigan use 10, Indiana uses 12, and Alabama uses 13. New York, Arizona, and Washington mix letters and digits. Check your state's claims manual or 837P companion guide, and copy the number from the eligibility check.
Is the Medicaid ID the same as the health plan member ID?
Not always. The NUCC instructions for box 1a (version 13.0, July 2025) say to enter the ID shown on the card for the payer you are billing, and to use the payer's own member ID if it assigned one. Bill the state with the state's number and a health plan with the plan's number.
Why does a Texas rider have two numbers?
Texas Medicaid numbers are 9 digits, but the fee-for-service Medical Transportation Program puts a 10-digit MPCN on its authorization form. As of September 2026, MTP claims want that MPCN in box 1a, and claims under the main Texas Medicaid rules want the 9-digit number. The MTP handbook does not apply to managed care rides, so follow the health plan's rules for those.
Do I enter the extra numbers printed on the card?
Only if the state asks. South Dakota's card shows a 3-digit generation number next to the 9-digit recipient ID, and its manual (updated September 2026) says not to put the generation number on a claim. Medi-Cal is the reverse in one case: when its eligibility system asks for the current card ID and issue date, claims without them are denied.
Which denial codes point to a bad member ID?
Reason code 31 means the patient cannot be identified as the payer's insured, reason code 140 means the ID number and name do not match, and remark code N382 means the patient identifier is missing, incomplete, or invalid. On a claim acknowledgment, status code 30 means the subscriber and ID do not match, and 33 means they were not found.