Why was my superbill rejected? 7 fixable causes

1. The NPI is missing or malformed (CO-16)

A claim that arrives without a valid individual NPI (Type 1) is stopped before a human reads it. It is also one of the cheapest problems to fix: ten digits, no spaces, no dashes.

The ten digits are not arbitrary. The last digit of an NPI is a check digit computed over the first nine (the CMS algorithm prepends the 80840 prefix and runs a Luhn-style sum). A transposed pair of digits still looks like a ten-digit number, so a length check alone will not catch it. The pre-check in this tool validates the check digit as well as the length.

Group practices have a second number: the Type 2 NPI for the PLLC or Inc. If the billing entity is the group, the superbill should show both.

2. Place of service is missing or wrong (CO-16, RARC M77)

Place of service is a required field on the service line, and it is the field therapists most often leave blank on a home-made superbill. A payer that cannot tell where the service happened cannot price it.

For telehealth it is worse than blank: POS 11 (office) is not an acceptable telehealth place of service for some major payers, and modifier-only telehealth claims (modifier 95 with no POS 02 or 10) are not payable. See the dedicated POS 02 / 10 / 95 page for the details.

3. The modifier does not match the service (CO-4)

CO-4 means the procedure code is inconsistent with the modifier, or a required modifier is missing. In behavioral health that usually means one of two things: a telehealth visit with no modifier 95 at all, or modifier 95 on a visit that was not synchronous audio-video.

Modifier 95 describes real-time, interactive audio and video. Audio-only visits use 93 or FQ depending on the payer, and GT is now only required by some Medicaid programs and a few commercial plans. Because the rules genuinely differ, the tool warns rather than blocks — confirm with the payer for the plan you are billing.

4. The diagnosis pointer does not support the CPT (CO-11)

Superbills borrow the CMS-1500 convention: up to four ICD-10 codes sit in Box 21 labelled A–D, and every service line carries one or more letters in Box 24E. A line that points at an empty slot, or at a code that does not plausibly support the procedure, is a CO-11 waiting to happen.

Two failure modes dominate. The first is mechanical: the letter points at slot C while slot C was never filled in. The second is a pairing problem — a psychotherapy code (90791, 90832, 90834, 90837, 90846, 90847) billed against a diagnosis that is neither an F (mental disorder) nor a Z (factors influencing health) code. The tool treats the mechanical error as blocking and the pairing question as a tip, because only the clinician and the payer can settle the second one.

5. The same code appears twice on one date (CO-97)

CO-97 means the benefit is included in another service already paid. Two 90837 lines on the same day is the classic trigger: payers read it as duplicate billing rather than two appointments.

If a client genuinely had two contacts in a day, the answer is usually different codes (an intake plus a session, or a family session plus an individual one) and a note that explains it — not the same code twice. Some payers also refuse to pay 90791 and 90837 on the same date at all.

6. The member cannot be found (CO-31)

CO-31 is "the patient is not covered under this plan" — in practice almost always a data mismatch: a nickname instead of the legal first name, a married name the plan never saw, a member ID with a dropped digit, or a date of birth typed in the wrong format.

Spell the client name exactly as it appears on the insurance card, and include the member ID and, when the client is a dependent, the policyholder name and relationship.

7. It was submitted too late (CO-29)

Most commercial plans close timely filing somewhere between 90 and 180 days after the date of service; the exact window is in the plan document. A superbill that sits in a client’s inbox for four months can be perfectly accurate and still unpayable.

The pre-check warns at 60 days and turns urgent past 90 days. That is deliberately conservative: it nudges you while there is still room to spare, and it does not pretend to know your specific plan’s deadline.

What actually fixes this

None of the seven causes above requires clinical judgment to detect. They are format rules: ten digits, a POS value, a modifier that matches the modality, a pointer that resolves, no duplicate line, a member ID, a date window. That is exactly the kind of check a browser can run in a millisecond without uploading anything.

The free pre-check in this tool runs all of them against your data before the PDF is generated. Blocking items disable the download; warnings and tips let you decide. Nothing about the client leaves your device, so there is no BAA conversation and no cloud copy to worry about.

The app only sends your license key and a device id to our license check (which asks Creem) — no patient or practice data ever leaves your browser.

Related

• Telehealth superbills: POS 02 vs 10 vs 11 and when modifier 95 applies
• Good Faith Estimate for therapists: the four required disclosures
• Can you use an FSA for therapy? The five fields a claim needs