Medi-Cal covers roughly 15 million Californians, so most small practices treat its patients sooner or later. The payments are real, and so are the rules.
A missed deadline or a missing authorization can turn a billable visit into unpaid work. Small practices feel that quickly because they have little cash flow to spare. Here are the mistakes that cost them the most:
1. Filing Too Late
Medi-Cal expects original fee-for-service claims to reach it within six months of the month of service. Claims that arrive in months seven through twelve are paid at a reduced rate and need a documented reason for the delay.
After a year, most are denied outright. Practices that batch claims or let them sit in a queue run into this limit without noticing. Medical billing services in California can track those deadlines for a small office.
2. Skipping Eligibility Checks
A patient who was covered last month may not be covered today. Practices that skip the check at each visit often learn about the problem only when the claim comes back denied. The state’s Medi-Cal Eligibility Verification System settles the question before treatment, not after.
The stakes are rising too. For applications filed from January 1, 2027, retroactive coverage shrinks from three months to one or two, depending on the member.
3. Treating Authorization as an Afterthought
Many Medi-Cal services need prior approval. Fee-for-service patients require a Treatment Authorization Request, while each managed care plan runs its own authorization rules and portals. A service delivered without the right approval is a service the practice may never be paid for.
Build authorization into scheduling, not billing. Dental offices face the same pressure under Denti-Cal, a separate program with its own rules. Dental billing services built for California can keep those authorizations straight.
4. Assuming Every Plan Works the Same
Medi-Cal is not one payer. Members belong to managed care plans operating under several models, and each plan has its own edits, portals, and rules.
A claim that clears one plan can bounce at another, so tracking each plan’s requirements separately is worth the effort. One rule change can raise denials across an entire patient group, and the practice often finds out weeks later.
5. Letting Denials and Late Payments Sit
Under California’s AB 3275, health plans must pay complete claims received since January 1, 2026, within 30 calendar days or owe 15 percent annual interest. That protection only helps practices that notice.
Unpaid claims need follow-up on a schedule, and denials need appeals before deadlines pass. Waiting for the next billing cycle often means waiting too long.
6. Billing Medi-Cal Before Other Insurance
Medi-Cal is the payer of last resort. When a patient also has private insurance or Medicare, that coverage must be billed first.
The Medi-Cal claim then needs the other payer’s explanation of benefits or denial letter, and the practice cannot bill the patient a copay or deductible.
What Can Practices Do About These Mistakes?
Most of these mistakes share one cause. Billing competes with patient care for a small team’s time. A short weekly routine fixes most of them, and one person should own it. Run through these six steps each week.
Pull each unsent claim and file anything nearing the six-month limit.
Verify eligibility for next week’s Medi-Cal patients and note any other coverage on file.
Confirm authorizations for upcoming services, including each plan’s own requirements.
Check that claims for patients with other insurance went to that payer first.
List claims unpaid past 30 days and follow up with the plan.
Review new denials and appeal before the deadline passes.
Dental offices can run the same list after confirming the patient’s program, since Denti-Cal has its own rules. A practice that treats both keeps one list for each. Even a short weekly review catches most of these problems before they become write-offs.
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