How does Counterclaim generate an insurance appeal letter?

Counterclaim uses a 5-agent AI pipeline. The Reader extracts claim data from your document. The Researcher identifies applicable state insurance law. The Writer drafts a formal appeal letter. The Adversary identifies weaknesses. The Editor rewrites the letter to eliminate all weaknesses. The final letter is ready to print and mail in minutes.

Is Counterclaim free to use?

Yes - Counterclaim is free during the launch period. Upload your denial letter and receive a complete adversary-tested appeal letter at no cost. No account required.

What types of insurance denials can Counterclaim handle?

Counterclaim handles all major denial types: medical necessity (CO-50), prior authorization (CO-11), experimental treatment (PR-1), fee schedule (CO-45), timely filing (PR-27), not covered (CO-4), step therapy (PR-50), and missing information (CO-16).

What file formats does Counterclaim accept?

Counterclaim accepts PDF files, JPG and PNG photos, and scanned documents of your denial letter or Explanation of Benefits (EOB).

Does Counterclaim provide legal advice?

No. Counterclaim generates appeal letters based on publicly available legal and clinical information but does not constitute legal advice. For complex cases, consult a licensed healthcare attorney or certified patient advocate.

What does CO-167 mean on my Explanation of Benefits?

CO-167 means 'this (these) diagnosis(es) is (are) not covered.' The insurer is denying the claim because the diagnosis code submitted does not support coverage for the billed service under its policy. This can be a genuine coding mismatch or an improper exclusion of a condition the plan is required to cover.

Is CO-167 usually a coding error?

Very often, yes. If the ICD-10 diagnosis code on the claim is incorrect, too non-specific, or does not match the medical coverage policy for the procedure, the insurer denies it. Ask your provider's billing office to review the diagnosis code against your medical record and the insurer's coverage policy, then submit a corrected claim with the appropriate, more specific code.

Can the insurer legally exclude my diagnosis?

Not always. While plans can exclude some conditions, many exclusions are overridden by law. The ACA requires coverage of essential health benefits and certain preventive screenings at no cost. The Mental Health Parity and Addiction Equity Act requires equal treatment of mental health and substance use diagnoses. Many states mandate coverage for specific conditions. If your denied diagnosis falls into one of these protected categories, the exclusion may be unlawful.

What documentation do I need to appeal a CO-167 denial?

Gather: the corrected or confirmed ICD-10 diagnosis code from your provider; the medical records establishing your diagnosis; the insurer's coverage policy for the service; and, if the denial is an improper exclusion, the relevant state mandate or federal statute (ACA, MHPAEA) that requires coverage. A letter from your treating physician linking the diagnosis to the medical necessity of the service strengthens the appeal.

How is CO-167 different from a medical necessity (CO-50) denial?

CO-50 says the service is not medically necessary. CO-167 says the diagnosis itself is not covered for that service. The fix differs: CO-50 calls for a letter of medical necessity and clinical evidence, while CO-167 usually calls for verifying or correcting the diagnosis code first, and only then arguing improper exclusion if the code is right but the plan still refuses.

CO-167

How to Appeal a CO-167 'Diagnosis Not Covered' Denial

Claim denied with CO-167 because the diagnosis is not covered? This is often a coding mismatch or an improper exclusion of a mandated benefit. Learn how to fix the code or appeal.

What does CO-167 mean?

A CO-167 denial means the insurer is refusing payment because the diagnosis code on the claim is not covered for the service billed. In practice this usually arises in one of two ways: the diagnosis (ICD-10) code on the claim does not support the procedure under the plan's coverage policy, or the plan is excluding coverage for a condition that state or federal law may actually require it to cover.

Why insurers issue CO-167 denials

CO-167 is frequently a coding problem. Insurers maintain medical coverage policies that list which diagnoses justify a given procedure, if the diagnosis code submitted is too vague, outdated, or simply the wrong code for your actual condition, the claim is denied even though the care was appropriate. The other major cause is improper exclusion: a plan denies a diagnosis (for example certain mental health, substance use, gender-affirming, or preventive screening diagnoses) that it is legally required to cover under the ACA, mental health parity law, or a state mandate.

Appeal strategy

First, ask your provider to verify the ICD-10 diagnosis code on the claim and confirm it accurately reflects your condition and supports the procedure under the insurer's coverage policy, a corrected diagnosis code often resolves CO-167 with no formal appeal. If the diagnosis is correct and the plan is excluding the condition itself, request the specific exclusion language and check it against your state's mandated benefit laws and federal mandates. The ACA, the Mental Health Parity and Addiction Equity Act, and state coverage mandates frequently override a plan's attempt to exclude a covered diagnosis.

Frequently asked questions about CO-167

CO-50

Medical Necessity Denial (CO-50)

CO-11

Prior Authorization Denial (CO-11)

CO-55

Experimental Treatment Denial (CO-55)

CO-45

Exceeds Fee Schedule Denial (CO-45)