Medical Billing Blog: Tips and Industry Updates

Our medical billing blog shares practical tips, coding changes and industry updates to help your practice get paid faster.

Written by our billing and credentialing team. Browse articles on denial management, A/R management, medical coding and credentialing.

CO 45 denial code explained: charge exceeds fee schedule or contracted rate
Insurance Claims and Reimbursement • Oct 2026

What the CO 45 Denial Code Means and How to Handle It

The CO 45 denial code means the charge you billed was higher than the payer’s fee schedule, maximum…

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CO 22 means the payer believes another plan should pay first, so the fix starts with billing order.
Insurance Claims and Reimbursement • Oct 2026

What the CO 22 Denial Code Means and How to Resolve It

The CO 22 denial code means the payer believes another insurance plan should pay this claim first. It…

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CO 4 denial code explained: the procedure code does not match the modifier
Coding • Oct 2026

What the CO 4 Denial Code Means and How to Fix It

The CO 4 denial code means the payer found that the procedure code on a claim line does…

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CO 27 denial code explained: expenses incurred after coverage terminated
Accounts Receivable (A/R) Management • Oct 2026

What the CO 27 Denial Code Means and How to Respond

The CO 27 denial code means the payer says the patient’s coverage had ended before the date of…

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CO-16 denial code guide: provider responsible, lacks information, remark code names the field, correct and resubmit
Medical Billing • Oct 2026

What the CO-16 Denial Code Means and How to Fix It

The CO 16 denial code means the payer could not process a claim because it lacks required information…

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CO-29 denial code guide: provider responsible, filing limit passed, dated proof, prevention tips
Insurance Claim Denials • Oct 2026

CO-29 Denials: Why Claims Miss the Filing Limit and What to Do

The CO 29 denial code means the payer says the time limit for filing the claim has expired.…

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