Guides
Plain-language explanations of medical billing codes, denial reasons, and your appeal rights.
CO-50 Denial Code: What It Means for Patients with Private Insurance
Learn what a CO-50 denial code means on your EOB, who is financially responsible, and how to appeal if you have private insurance.
CO-4 Denial Code: Missing or Incorrect Procedure Modifier
A CO-4 denial means the claim was adjusted due to a missing or incorrect procedure modifier. This is one of the most fixable denial codes.
CO-16 Denial Code: Missing or Incomplete Information on Your Claim
A CO-16 denial means your insurer adjusted the claim due to missing or incomplete information. This is a fixable administrative error.
CO-96 Denial Code: Service Not Covered by Your Insurance Plan
A CO-96 denial means the service is not a covered benefit under your insurance plan. Unlike CO-50, the plan excludes the service entirely.
PR-50 vs CO-50: What the Group Code on Your EOB Means for Your Wallet
PR-50 and CO-50 both mean 'not medically necessary,' but they have opposite financial outcomes. Learn which one means you owe money.
How to Read Your Explanation of Benefits (EOB): A Plain-Language Guide
Your EOB tells you what your insurance paid and what you may owe. Learn how to read every section, decode CARC and RARC codes, and spot errors.
The No Surprises Act Explained: What It Covers and Who It Protects
The No Surprises Act protects you from unexpected out-of-network medical bills. Learn what's covered, what's not, and how to assert your rights.
Insurance Appeal Deadlines by State: How Long You Have to File
Appeal deadlines vary by state and plan type. Learn federal minimums, state-specific timelines, and how to find your exact appeal window.
Medical Billing Glossary: Insurance and Billing Terms Explained
A plain-language glossary of medical billing and insurance terms — EOB, prior authorization, balance billing, deductible, coinsurance, CPT codes, and more.