California Medical Billing Guide: Payers, Laws and Rules

Department of Managed Health Care (DMHC)

The DMHC licenses and regulates health care service plans under the Knox-Keene Health Care Service Plan Act of 1975. That covers every HMO, most PPO and POS products sold by plans such as Blue Shield of California and Anthem Blue Cross, Medi-Cal managed care plans, and the risk-bearing medical groups and IPAs that pay claims on a plan's behalf.

For billing teams, the DMHC enforces the claims settlement rules in 28 CCR §1300.71 (often called the AB 1455 regulations), the provider dispute resolution rules, timely access standards and the AB 72 independent dispute resolution process (IDRP). Providers can file a complaint through the DMHC Provider Complaint Unit when a plan or delegated IPA ignores these rules.

California Department of Insurance (CDI)

The CDI regulates health insurance policies issued under the Insurance Code, which are mostly PPO and indemnity products. CDI-regulated insurers follow parallel prompt-pay rules in Insurance Code §10123.13 and §10123.147 and the same AB 72 payment standard. Check the patient's ID card or the plan's evidence of coverage; it usually names the regulator.

Department of Health Care Services (DHCS)

DHCS administers Medi-Cal, California's Medicaid program. It publishes the Medi-Cal Provider Manual, runs provider enrollment through PAVE, processes fee-for-service claims through its fiscal intermediary, reviews Treatment Authorization Requests (TARs) and audits paid claims. Its Audits and Investigations division can recoup overpayments, withhold payments or suspend providers.

California Attorney General

The Attorney General's Division of Medi-Cal Fraud and Elder Abuse prosecutes Medi-Cal fraud. The AG also enforces SB 1061 medical debt rules and patient privacy protections, and brings actions under the California False Claims Act, which allows treble damages plus per-claim penalties.

Medical Board of California

The Medical Board licenses physicians and can discipline them for billing-related misconduct, such as billing for services not provided or repeated fraudulent claims. Insurance fraud is also a crime under Penal Code §550.

Federal agencies that still apply

CMS sets Medicare rules and federal Medicaid requirements, the HHS Office of Inspector General (OIG) enforces fraud and abuse laws, and the U.S. Department of Labor oversees self-funded ERISA plans. California's state laws do not reach self-funded employer plans; the federal No Surprises Act governs those patients' surprise-billing protections.

Medi-Cal (California's Medicaid program)

Medi-Cal covers roughly one in three Californians, so almost every practice sees Medi-Cal patients. It pays through two channels:

• Fee-for-service (FFS): You bill DHCS directly through the Medi-Cal fiscal intermediary. FFS still covers certain services and populations carved out of managed care.

• Managed care: Most members are enrolled in a Medi-Cal managed care plan chosen or assigned by county, such as L.A. Care, Health Net, IEHP, CalOptima Health, CenCal Health, Partnership HealthPlan or Kaiser Permanente. You bill the plan, or the IPA the plan delegates to, under that plan's contract and portal.

Three Medi-Cal rules trip up billers new to California:

1. Enrollment comes first. Only providers enrolled and active through DHCS's PAVE portal can bill Medi-Cal. Managed care plans also require their own credentialing.

2. Retroactive eligibility. Medi-Cal can cover services up to three months before the month a patient applies. A visit billed as self-pay may become billable to Medi-Cal later, and the filing clock adjusts under a delay-reason code.

3. Payment in full. Once you accept a patient as Medi-Cal, you cannot balance-bill them for covered services beyond any Share of Cost.

Commercial payers and managed care

California's commercial market leans heavily on managed care. Many HMO members are assigned to an IPA or medical group that holds capitated risk and pays specialist claims itself under a Division of Financial Responsibility (DOFR). The same claim can be the health plan's responsibility for one service and the IPA's for another, so sending the claim to the correct payer is the first clean-claim check.

Whether the product is DMHC- or CDI-regulated, all fully insured commercial plans now follow the 30-calendar-day payment rule and the AB 72 out-of-network standard.

Medicare in California

Original Medicare claims in California go to Noridian Healthcare Solutions, the Medicare Administrative Contractor for Jurisdiction E (JE). Noridian publishes the Local Coverage Determinations (LCDs) that decide medical necessity for many services. Medicare's 12-month filing limit, its fee schedule and its appeal levels apply here as everywhere.

California's twist is geography: the Medicare Physician Fee Schedule pays different amounts across California's many payment localities, so a CPT code pays more in San Francisco than in Fresno. Dual-eligible patients (Medicare and Medi-Cal, known as Medi-Medi) must be billed to Medicare first, with Medi-Cal as payer of last resort.

1. Prompt pay law: AB 3275 and the 30-calendar-day rule

Many guides still quote California's old "30 working days" rule, or 45 working days for HMOs. That rule ended for claims received on or after January 1, 2026. Under AB 3275, every health care service plan, including HMOs and Medi-Cal managed care plans, and every health insurer must:

• Pay a complete claim within 30 calendar days of receipt, weekends and holidays included.

• Send written notice within 30 calendar days if it contests or denies a claim, naming what information it needs.

• Re-decide a contested claim within 30 calendar days after receiving the requested information.

• Pay 15% annual interest starting on day 31, and add the greater of $15 or 10% of the accrued interest if it fails to include that interest automatically (H&S Code §1371.35).

What to do: Update your A/R follow-up queues to flag commercial and Medi-Cal managed care claims at day 31, and audit remittances for missing interest. Few practices check for it, and payers rarely volunteer it.

2. Timely filing protections: 28 CCR §1300.71

California limits how short a plan's filing deadline can be. A DMHC-regulated plan cannot impose a deadline of less than 90 days from the date of service for contracted providers or 180 days for non-contracted providers. For secondary claims, the deadline cannot be less than 90 days from the primary payer's payment or denial (CMA summary). A denial for timely filing can be overturned through the plan's dispute process if you show good cause.

Keep the plan's electronic acknowledgment (277CA) or clearinghouse report for every claim. It is your proof of timely filing.

3. Surprise billing protections: AB 72 and the No Surprises Act

AB 72 took effect July 1, 2017. It applies when a non-contracted individual health professional, such as an anesthesiologist, radiologist, pathologist or assistant surgeon, provides non-emergency covered services at an in-network hospital, ambulatory surgery center or lab.

• The patient pays only in-network cost sharing.

• The plan pays the provider the greater of its average contracted rate or 125% of Medicare for the same service in the same region.

• Either side can take a payment dispute to the binding Independent Dispute Resolution Process (IDRP) run by DMHC and CDI.

• The provider may bill out-of-network rates only with the patient's written consent given at least 24 hours in advance, plus the required disclosures.

AB 72 covers state-regulated plans. For self-funded ERISA plans, and for emergency services, the federal No Surprises Act (effective January 1, 2022) governs, with its own federal IDR process and Good Faith Estimate rules for uninsured and self-pay patients.

4. Medical privacy: CMIA vs HIPAA

The Confidentiality of Medical Information Act (Civil Code §56.36 text) is stricter than HIPAA in three ways that matter to billing:

For billing, CMIA means tighter written authorizations before releasing records to anyone other than the payer, encrypted claim attachments, role-based access in your practice management system, and a CMIA clause, not just a HIPAA BAA, in contracts with billing vendors.

5. Medical debt and credit reporting: SB 1061

SB 1061 changed patient collections for every California provider, not just hospitals:

• Since January 1, 2025, providers, billing companies and collection agencies may not furnish any medical debt to a consumer credit reporting agency. Knowingly doing so makes the debt void and unenforceable.

• Since July 1, 2025, any contract that creates a medical debt, such as a payment plan or financial responsibility agreement, must contain the exact disclosure set out in Civil Code §1785.27(c). A contract missing that language is void.

What to do: Update patient financial agreements and payment plan forms now, and confirm in writing that your collection agency never reports to credit bureaus.

Hospitals face additional duties under the Hospital Fair Pricing Act (H&S Code §127400 et seq.), including charity care and discount payment policies and extended payment plans for eligible patients. Physician practices are not bound by that Act, but its standards are a useful benchmark for patient-friendly collections.

6. Provider dispute resolution (PDR)

Every DMHC-regulated plan and delegated IPA must run a fast, fair provider dispute process. A structured denial management workflow keeps those deadlines visible. Under 28 CCR §1300.71.38, you have 365 days from the plan's action to file a dispute, and the plan must decide it within 45 working days. If the plan or IPA fails to follow the process, escalate to the DMHC Provider Complaint Unit.

Prior authorization and Medi-Cal TARs

A Treatment Authorization Request (TAR) is Medi-Cal fee-for-service's prior authorization. Certain procedures, durable medical equipment, inpatient stays and drugs require an approved TAR before the claim will pay. Most TARs are submitted electronically (eTAR) through the Medi-Cal provider portal, and the TAR control number must appear on the claim.

Medi-Cal managed care plans and commercial HMOs run their own prior authorization or referral systems, often delegated to the patient's IPA. Three rules prevent most authorization denials:

1. Check the plan's and the IPA's authorization lists, which may differ.

2. Match the CPT, units and date range on the claim to the approved authorization exactly.

3. Request retro-authorization immediately after urgent care that skipped the normal process, inside the plan's stated window.

Eligibility verification

Verify coverage at every visit, not just the first. Medi-Cal eligibility is checked through the Medi-Cal Medical Eligibility Verification System (MEVS), available on the provider portal, by phone (AEVS) or through point-of-service devices. A MEVS response tells you:

• Whether the patient is eligible for that month

• The assigned managed care plan, if any, so you bill the plan rather than DHCS

• Share of Cost (SOC) obligations that must be met or cleared before Medi-Cal pays

• Other health coverage that must be billed first

Save the MEVS eligibility confirmation number with the encounter; it protects you if eligibility is later disputed. For commercial patients, run an electronic 270/271 check and confirm the capitated IPA or medical group for HMO members.

Timely filing limits in California

California deadlines differ by payer type, and Medi-Cal counts from the end of the month of service, not the date of service.

Medi-Cal accepts late claims without penalty only for recognized delay reasons under W&I Code §14115, such as retroactive eligibility, delays caused by other coverage or a patient who did not identify as a Medi-Cal beneficiary. Each needs the correct delay-reason code and supporting documentation.

Unethical coding practices

Improper balance billing

California limits what you can bill a patient after the payer pays:

• Medi-Cal patients: No billing for covered services beyond any Share of Cost. Medi-Cal payment is payment in full.

• HMO patients: Under Knox-Keene, contracted providers cannot bill HMO enrollees for amounts the plan or IPA owes, even if the plan or IPA fails to pay.

• Out-of-network at an in-network facility: AB 72 limits the patient to in-network cost sharing unless the written 24-hour consent rules are met.

• Emergency services: Patients covered by state-regulated plans or the No Surprises Act cannot be balance-billed for emergency care beyond in-network cost sharing.

Collect only the copay, coinsurance, deductible or non-covered charges shown on the EOB or remittance advice.

Triggers for billing audits

Payers, DHCS and federal contractors use data analytics to pick audit targets. Watch for these red flags in your own data first:

1. E/M level drift: a provider billing 99214 and 99215 far more than specialty peers.

2. Sudden spikes in a CPT code, modifier 25 or 59 use, or units per visit.

3. Documentation gaps: cloned notes, missing signatures, or time-based codes without documented time.

4. Patient complaints to the DMHC, CDI or Medical Board about charges.

5. High denial rates for medical necessity against Noridian LCDs.

6. Enrollment mismatches: billing from a service location not enrolled in PAVE.

If you receive an audit letter, calendar every deadline, preserve records exactly as they are, and involve a healthcare attorney before responding.

Run routine internal billing audits

Audit a random sample of 10 to 20 encounters per provider each quarter. Compare documentation to the codes billed, check modifiers, and confirm the claim went to the right payer under the DOFR. Track findings over time; a falling error rate is your best defense if an outside auditor arrives.

Train staff on California-specific updates

Build a short annual training around the changes that hit California practices directly: AB 3275's 30-calendar-day rule (2026), SB 1061's contract language (2025), Medi-Cal provider bulletins, Noridian LCD updates and January CPT changes. Keep sign-in records; regulators look for them.

Weigh the ROI of a California-specialized billing partner

Outsourcing makes sense when your team cannot keep pace with California's rule changes, when A/R over 90 days keeps growing, or when Medi-Cal and IPA claims are a large share of revenue. That is where full revenue cycle management pays for itself. A national billing company may know CPT codes but miss DOFR routing, Medi-Cal month-of-service deadlines or the interest you are owed under AB 3275. Ask any vendor how it handles each of those before signing.

California billing compliance checklist

• Every provider and service location is enrolled and current in PAVE, and credentialed with each Medi-Cal managed care plan and IPA

• Eligibility checked every visit through MEVS or a 270/271, with the confirmation saved

• Assigned Medi-Cal plan, IPA and DOFR responsibility confirmed before the claim is built

• TAR or prior authorization number on every claim that needs one

• Medi-Cal claims submitted well inside 6 months after the month of service

• Commercial filing deadlines tracked by contract, never less than 90 or 180 days

• Day-31 follow-up queue for unpaid complete claims, with interest checked on late payments

• Provider disputes filed within 365 days and tracked to a 45-working-day answer

• AB 72 consent forms on file before any out-of-network billing at in-network facilities

• Patient financial agreements include the SB 1061 Civil Code §1785.27 clause

• Collection agency confirmed in writing never to report medical debt to credit bureaus

• CMIA and HIPAA terms in every billing vendor and software contract

• Quarterly coding audit completed and documented

• Annual staff training on California updates completed and logged

Need help with any item on this list? Our California medical billing services team can review your claims against every rule in this guide.