Medi-Cal Billing: The Complete 2026 Guide

Medi-Cal is California's Medicaid programme, administered by the Department of Health Care Services (DHCS). The first decision on every Medi-Cal claim is which delivery system the member is in that month, because that decides where the claim goes.

DHCS states the enrolment sequence plainly on its Medi-Cal Managed Care Health Plan Directory: "When you first qualify for Medi-Cal, you are covered under Medi-Cal Fee-for-Service. Depending on the county where you live, you may have to choose a health plan within 30 days. If you do not choose a health plan within 30 days, Medi-Cal will choose a health plan for you." DHCS adds that in some counties a member is automatically enrolled in a plan without selecting one. (DHCS, Medi-Cal Managed Care Health Plan Directory; page last modified 31 July 2026, read 17 September 2026.)

That sequence is the operational point: a member can be fee-for-service in one month and managed care the next, entirely through the normal working of enrolment. It is not an edge case, and it is why a stale eligibility check is the single largest root cause of Medi-Cal routing denials.

Managed care. The member is enrolled in a Medi-Cal Managed Care Plan (MCP). DHCS pays the plan, and the plan adjudicates and pays your claims under its own contract, portal and timely-filing window. You bill the plan, not the state. Each MCP can require its own prior authorizations and apply its own claim edits.

Fee-for-service. The member is not enrolled in an MCP — because they have just qualified, because of their aid category, or because of a carve-out. Claims go to the state's fiscal intermediary and pay off the published Medi-Cal fee schedule, with prior authorization handled through the TAR process.

The non-negotiable first step on every Medi-Cal claim is therefore a current-month eligibility verification that returns both eligibility and the assigned plan. Billing the wrong entity — the state when the member is in managed care, or the previous MCP after a plan change — produces denials that look like coverage problems but are really destination problems. Front-end insurance eligibility verification that re-checks every month is the highest-yield fix available on this programme.

Which plans operate in a county, and whether the member has a choice, is governed by the county's managed care model. DHCS publishes five models, not the three or four that most guides list. Its "Medi-Cal Managed Care Models" county map — the document DHCS links from its plan directory as the authority on models by county — carries the legend Regional Model, COHS Model, Two Plan Model, GMC Model and Single Plan Model, and the map is stamped as of January 1, 2024. (Read 17 September 2026.)

What each model means for routing:

• County-Organized Health System (COHS). A single plan covers the county's managed-care members; there is no member plan choice. Once you have confirmed the county and that the member is in managed care, the routing question is settled.
• Single Plan. One commercial plan operates in the county. Same routing consequence as COHS for your purposes, different contracting history.
• Two Plan. Members choose between two plans, historically a public "Local Initiative" and a commercial partner. You may be contracted with one or both, and you must route each claim to the member's specific plan.
• Geographic Managed Care (GMC). Members choose among several competing commercial plans in the same geography. You may be contracted with several in one county and must read each member's plan every month.
• Regional. A model DHCS applies across a group of counties. Treat it like Two Plan or GMC for routing purposes: read the member's specific plan from eligibility rather than inferring it from the county.
• Fee-for-service sits outside the model structure — it is where a member starts before plan enrolment, and where some aid categories and carve-outs remain.

Why you should date this and re-check it. DHCS restructured its Medi-Cal managed care commercial-plan contracts effective 1 January 2024, and the county map above carries that same effective date. Plan footprints move with contract cycles, and the model tells you the structure while the county directory tells you the names. DHCS maintains a county-by-county plan directory for exactly this purpose, and it is the source of truth — not a list in a guide, including this one. Confirm the current plan list for the county before you contract or route claims.

We previously published a table mapping named Medi-Cal plans to counties. We have removed it, because we could not verify the county-by-county assignments against a current DHCS source, and a plan-to-county map that is even slightly stale sends claims to the wrong payer — which is the exact failure this page exists to prevent.

The reliable procedure has three steps and no lookup table:

1. Read the plan off the eligibility response, every month. An AEVS or 270/271 check for the date of service returns whether the member is in managed care and, if so, which plan. This is authoritative for that member for that month; a county-level list never is.
2. Confirm the county's current plan list in the DHCS Medi-Cal Managed Care Health Plan Directory before contracting or setting up a new payer. DHCS publishes it county by county and maintains it; the version read for this guide was last modified 31 July 2026.
3. Check the county's model in the DHCS Medi-Cal Managed Care Models county map to know what to expect. In a COHS or Single Plan county there is one plan and no member choice, so the county answers the question. In Two Plan, GMC and Regional counties there are several, so only the member's own eligibility response answers it.

Three operational notes that survive any plan-list change:

1. Each plan has its own portal, claim address, payer ID and corrected-claim process. Submitting a managed-care member's claim to fee-for-service, or to the plan they left last month, produces eligibility and routing denials that read like coverage problems. For how Medi-Cal managed care fits the wider Medicaid picture, see the Medicaid MCO glossary entry and the general Medicaid glossary entry.
2. Plan-level edits differ. A claim that pays cleanly under one MCP may need different modifier or place-of-service handling under another, so a single "Medi-Cal" edit set is never enough — maintain rules per plan.
3. Dual-eligible members may be in a Medi-Medi Plan. DHCS notes that for people with both Medicare and Medi-Cal, Medi-Medi Plans — Medicare Advantage plans combining Medicare and Medi-Cal benefits — are available in certain counties for voluntary enrolment, and publishes a separate directory for them. A dual whose eligibility response shows a Medi-Medi Plan is not routed like a Medi-Cal-only member.

Share of Cost is one of the most misunderstood mechanics in Medi-Cal billing and a frequent source of patient-collection errors. Some Medi-Cal beneficiaries qualify with a Share of Cost — a dollar amount, recalculated each month from income, that the member must incur in healthcare charges before Medi-Cal begins to pay for that month. It behaves like a deductible that resets on the first of each month.

At the desk:

1. Verify SOC at eligibility. The monthly eligibility response tells you whether the member has a SOC, the amount, and how much has already been met for the month.
2. Clear or certify the SOC. Providers report obligations toward the SOC through the eligibility and SOC transaction so the state's ledger tracks the running total. Once the member has incurred charges equal to the SOC for the month, Medi-Cal coverage is active for the remainder of that month.
3. Bill correctly around it. Charges applied to an unmet SOC are the member's responsibility up to the SOC amount; the balance, once the SOC is met, bills to Medi-Cal or the MCP. Billing Medi-Cal for charges that should have cleared the SOC, or billing the member beyond the SOC amount, are the two errors that turn this into a compliance problem.

Brief the front desk on four things:

• SOC is monthly and resets — meeting it in March does nothing for April.
• SOC is not a copay; it is a spend-down threshold.
• A member with an unmet SOC can appear eligible in the system while Medi-Cal payment is suspended until the SOC is met for that month.
• Charges written down internally do not clear the state's SOC ledger. You have to use the certification process for the obligation to count.

The prevention play is the same as for plan routing: a disciplined monthly eligibility check that returns SOC status before the visit, so the front desk knows what the member owes and what bills to Medi-Cal. That is core patient billing and collections hygiene. Because the SOC amount and the met status are member-specific and month-specific, and because the SOC interacts with what you may lawfully collect, verify it from the eligibility response rather than from the last visit's notes.

A Treatment Authorization Request (TAR) is Medi-Cal's prior-authorization mechanism for fee-for-service. For specified services, supplies, equipment and procedures, an approved TAR must be on file before the service is rendered — or, for some categories, within a defined retroactive window. A claim submitted without a required approved TAR is denied, and a TAR cannot always be cured after the fact.

What requires a TAR is service-specific and defined in the Medi-Cal provider manual section for that service category. We are not publishing a list here, because the list is exactly the kind of thing that goes stale silently: check the current manual section for the service you are about to render, not a summary of it.

The managed-care equivalent. In Medi-Cal managed care the plan's own prior-authorization process replaces the FFS TAR. Each MCP publishes its own PA list, forms and turnaround standards. A service that needs a TAR in fee-for-service will generally need plan PA in managed care, but the form, portal and rules belong to the plan. Sending a TAR to the state for a managed-care member, or skipping the plan's PA because the state's TAR list does not include the service, both produce authorization denials.

The operational rule: check the TAR or PA requirement at scheduling, not at billing. Once the service is rendered without the required authorization, the options narrow to retro-authorization where the category and plan allow it, or appeal — both slower and lower-yield than obtaining it up front. Outsourced prior authorization services own this check at the front end so authorization denials never reach the A/R.

Medi-Cal's fee-for-service timely-filing rule is defined in months, not days, and the penalty is graduated rather than a single cliff. The source is the DHCS Medi-Cal provider manual section Claim Submission and Timeliness Overview (page updated January 2024; read 17 September 2026), which states: "Original (or initial) Medi-Cal claims must be received by Medi-Cal within six months following the month in which services were rendered." The manual calls this the six-month billing limit and cites Welfare and Institutions Code Section 14115 as its authority.

The graduated schedule, in the manual's own terms:

• Within six months following the month of service: the original claim is payable in full, subject to normal adjudication.
• Seventh through ninth month after the month of service: "Claims received during the seventh through ninth month after the month of service will be reimbursed at 75 percent of the payable amount."
• Tenth through twelfth month after the month of service: "Claims received during the tenth through twelfth month after the month of service will be reimbursed at 50 percent of the payable amount."
• After the twelfth month: "Claims received after the twelfth month following the month of service will be denied."

Note the shape of that: 75 percent and 50 percent of the payable amount, not reductions applied to your billed charge. And note the clock — it runs from the end of the month of service, not from the date of service, which is why the common "180 days" shorthand is imprecise and usually understates the time available.

The operational consequence. A Medi-Cal fee-for-service claim sitting past six months is not a write-off. It is a claim payable at 75 percent, and then at 50 percent, and it stays worth filing all the way to the twelfth month. Treating the six-month mark as a dead stop leaves recoverable revenue on the table. What you cannot do is pass the reduction on: a timely-filing reduction or denial is a provider write-off, not a patient balance.

Three more mechanics worth building into the workflow:

• Delay reason codes. The same manual section addresses delay reason codes, which exist for defined circumstances such as retroactive eligibility or other-coverage adjudication delays. They require the correct code and supporting documentation, and they are exceptions rather than a safety net — design the workflow to file inside six months as the default and treat delay codes as recovery, not strategy.
• Managed care plans set their own windows. Each MCP's provider contract defines its filing window for original claims and, separately, for corrected claims and disputes. These are not uniform across plans and are not the state's rule. Read your executed contract for each plan you bill rather than assuming a common range.
• Corrections have their own clocks. For fee-for-service, the Claims Inquiry Form process and the resubmission and appeal timelines are defined separately in the provider manual, and correcting a denied claim does not reset the original filing clock — so retain evidence of the original timely submission.

The practical takeaway is that the fee-for-service clock is graduated and absolute at twelve months. You protect it with a tight charge-lag-to-submission cycle plus an A/R cadence that surfaces unbilled and stalled Medi-Cal claims well before the six-month full-payment mark and long before the twelve-month cliff. Our accounts receivable follow-up services build the Medi-Cal follow-up calendar around that schedule and around each MCP's contracted deadline.

Medi-Cal denials cluster into a recognisable set, and most are preventable at the front end. The table maps each pattern to its root cause and fix, with the standard CARC family where one applies so the items slot into a normal denial worklist.

Two themes drive most of this list. Eligibility must be verified for the current month, every time — eligibility, plan assignment and Share of Cost all change monthly, and a stale check is the single largest root cause. Medi-Cal is the payer of last resort — where a beneficiary has any other liable coverage, that coverage bills first and Medi-Cal or the MCP pays the residual, so coordination-of-benefits sequencing errors are common and entirely preventable. Working these efficiently means categorising each denial by root cause at intake and routing it to the team that owns the prevention step; for volume Medi-Cal practices, outsourced denial management services can own the categorisation, the corrections and the feedback loop.

A practice that runs clean on Medi-Cal does the same handful of things on every claim, in order. The economics favour front-end discipline heavily: the fee-for-service clock reduces what a late claim is worth before it denies it, and eligibility changes monthly, so reactive rework is expensive while the prevention steps cost almost nothing per claim once standardised.

1. Verify eligibility every month, and capture the plan and the SOC. Run an AEVS or 270/271 check for the date of service. Read whether the member is fee-for-service or managed care, identify the exact MCP, and capture any Share of Cost amount and met status. This one step prevents the largest categories of Medi-Cal denial: wrong-entity routing, lapsed eligibility and SOC errors.

2. Confirm the TAR or plan PA at scheduling. Check the current provider manual section, or the plan's PA list, for the specific service before it is rendered — and then match the eventual claim's codes, units and dates to the approved authorization exactly.

3. Sequence other coverage first. Medi-Cal is the payer of last resort, so bill any primary coverage first and attach the primary remittance before billing Medi-Cal or the MCP.

4. Code, scrub and submit to the right destination. Validate codes and modifiers against current code sets and the plan's edits, then submit to the correct entity: the state fiscal intermediary for fee-for-service, or the assigned plan's payer ID and portal for managed care.

5. Work the A/R against the six-month and twelve-month marks. Maintain a follow-up cadence that surfaces unbilled and aging Medi-Cal claims before the six-month full-payment mark, and certainly before the twelve-month denial point, or before the MCP's contracted deadline. Use the correct correction path — the Claims Inquiry Form for fee-for-service, the plan's corrected-claim process for managed care — rather than resubmitting new originals.

6. Re-check the sources on a calendar. Plan footprints change with DHCS contract cycles and provider-manual pages carry their own update dates. Put a recurring review on the calendar for the DHCS plan directory, the managed care models map, and the provider manual sections for the services you bill most.

For practices billing across multiple counties and MCPs the operational complexity is real — different portals, different PA lists, different contracted filing windows, and monthly-shifting eligibility. That is the work revenue cycle management services tuned for California's Medi-Cal landscape are built to absorb.