New York Form C-4 is the Doctor’s Initial Report that a treating provider files with the New York Workers’ Compensation Board after the first visit for a work-related injury or illness. The form documents the diagnosis, causation, treatment plan, and degree of disability, and it triggers the medical record that supports a worker’s claim for wage replacement and medical care.
If you skip the form, file it late, or fill it out wrong, the injured worker can lose benefits, the doctor can lose payment, and the employer’s carrier can deny the claim outright under the rules in Workers’ Compensation Law §13. According to the New York WCB 2024 Annual Report, the Board processed more than 140,000 new indemnity claims last year, and medical reports drive almost every payment decision in those files.
Here is what you will learn in this guide:
- 📝 How to complete every line item of Form C-4 without triggering a Board rejection
- ⚖️ Why the Medical Treatment Guidelines and WCL §13-a control which boxes you check
- 💰 How billing, the fee schedule, and CMS-1500 electronic filing connect to the C-4
- 🚧 Three real scenarios — construction, office, and motor vehicle — with named-person examples
- 🛑 The most common mistakes that cause denied claims, unpaid bills, and §114-a fraud findings
What Form C-4 Is and Why It Exists
Form C-4, officially titled the Doctor’s Initial Report, is the first medical document a treating physician, chiropractor, podiatrist, dentist, or psychologist files after seeing an injured worker. The Board uses it to confirm that an injury is work-related, to set the degree of temporary disability, and to authorize the early phase of treatment under the Medical Treatment Guidelines. Without a properly filed C-4, the carrier has no medical proof to pay indemnity benefits, and the claimant can sit for weeks without a paycheck.
The form lives inside a larger family of medical reports. The base C-4 captures the initial visit, the C-4.2 captures every progress visit after that, the C-4.3 captures permanent impairment at maximum medical improvement, the C-4AMR covers ancillary medical evidence, and the C-4AUTH asks the carrier to approve treatment that exceeds the MTG variance rules. Each form feeds the same legal record, but each one answers a different question for the adjudicator.
The form exists because WCL §13-a requires every authorized provider to report the worker’s condition to the Board, the carrier, and the claimant within 48 hours of the first treatment. The statute exists to prevent silent treatment, hidden injuries, and fraud, and the consequence of ignoring it is a forfeiture of the bill plus possible removal from the WCB-authorized provider list. A common misconception is that an emergency room note is enough — it is not, because hospital records do not contain the disability rating language the Board needs.
The Shift From Paper C-4 to CMS-1500 eClaims
In 2022, the Board moved most authorized providers from the paper C-4 form to the CMS-1500 electronic billing standard paired with a narrative medical report. Providers now submit bills through an XML eClaims partner, and the narrative still has to contain every data element the old C-4 captured. The paper C-4 still exists for self-represented providers and for limited niche filings, so you must know both paths.
The consequence of using the wrong path is non-payment. If a chiropractor files a paper C-4 when the Board expects CMS-1500, the carrier can reject the bill as non-conforming under 12 NYCRR §325-1.3. A common misconception is that emailing a PDF C-4 to the adjuster counts as filing — it does not, because the Board’s electronic gateway is the only official filing channel for most providers.
Who Must File and Who May Not
Only a WCB-authorized provider may file a C-4 and bill the carrier under the Medical Fee Schedule. Out-of-state providers can treat New York claimants only in narrow situations, like a worker who lives near the border or who was injured while traveling, and they must request out-of-state authorization from the Board first. The consequence of treating without authorization is a complete loss of the bill, even if the care was excellent.
A common misconception is that any licensed New York doctor can simply start treating workers’ comp patients. The provider must register through the Board’s Health Provider Portal, pass a Medical Treatment Guidelines training course, and accept the fee schedule. Skipping registration is the single fastest way to work for free.
Line-by-Line Walkthrough of Form C-4
The paper C-4 has four pages and roughly 40 data fields. Every field has a purpose, and every blank field is a chance for the carrier to controvert the claim under WCL §25. Work through the form in the order the Board prints it, because the logic flows from identification to causation to treatment to disability.
Section A — Identification and Employer Information
Section A captures the worker’s full legal name, date of birth, address, Social Security number, gender, and the employer’s name and address at the time of injury. The Board uses this block to match the C-4 to the worker’s existing WCB case number or to open a new file under the Jurisdictional Case Number System. If the case number is wrong, the C-4 lands in an orphan queue and the worker waits.
The consequence of a missing or wrong employer name is a controverted claim. Carriers routinely deny claims when the named employer does not match the policy on file, because the carrier has no contractual duty to pay a stranger. A common misconception is that the worker’s current employer goes here — the field is for the employer on the date of injury, even if the worker has since changed jobs.
A real example: Maria Lopez, a home health aide, hurt her shoulder lifting a patient in March. She switched agencies in April, and her new doctor wrote the new agency on the C-4. The carrier denied the claim, and Maria spent six weeks fixing the record before her first check arrived.
Section B — Date, Time, and Place of Accident
Section B asks for the date of accident, the time of accident, the place of accident, and a short narrative of how it happened. The narrative must connect the injury to the job, because WCL §10 requires that the accident arise out of and in the course of employment. Vague phrases like “patient reports back pain” will not establish causation.
The consequence of a weak narrative is a §21 presumption fight. Carriers can rebut the presumption of compensability when the medical record does not describe a work event. A common misconception is that the doctor must witness the event — the doctor only has to record the worker’s history accurately, in the worker’s own words, and tie it to a medical opinion.
A real example: David Kim, a warehouse picker, told his doctor he “tweaked his back at work.” The doctor wrote that exact phrase. The carrier denied the claim because the note did not say which work activity. After the doctor amended the C-4 to say “lifting a 60-pound box from a low shelf,” the claim was established.
Section C — Patient History and Diagnosis
Section C is the clinical heart of the form. It asks for the chief complaint, the history of present illness, prior similar injuries, the objective findings on examination, the diagnosis with ICD-10 codes, and any imaging or test results. The Board cross-checks the ICD-10 codes against the Medical Treatment Guidelines body part list to decide which guideline applies.
The consequence of a wrong ICD-10 code is a denied authorization request. If the doctor codes a lumbar strain but treats a cervical disc, the C-4AUTH for cervical injections will fail. A common misconception is that one code per body part is enough — the Board expects every diagnosis the worker carries, including pre-existing conditions, so the carrier can apportion under WCL §15(7).
Section D — Causal Relationship Opinion
Section D asks the doctor to check yes or no on whether the injury is causally related to the work event described in Section B. The doctor must also indicate whether the condition is an aggravation of a prior problem, a new injury, or an occupational disease under WCL §3(2). This single checkbox often decides the entire claim.
The consequence of leaving the box blank is automatic controversion. Carriers read a blank causation box as “no opinion,” and an Administrative Law Judge will not establish a claim without a medical opinion on causation. A common misconception is that probable causation is too weak — New York actually accepts a “reasonable degree of medical certainty,” which is more than 50% likelihood, not 100%.
A real example: Janet Williams, a teacher with prior arthritis, fell on a wet hallway. Her doctor checked “yes — aggravation of pre-existing osteoarthritis.” The carrier paid for the acute care and apportioned 50% to the pre-existing condition at permanency, exactly as the Court of Appeals allowed in Matter of Bremer.
Section E — Treatment Rendered and Plan
Section E lists the treatment given on the visit, the treatment plan going forward, prescribed medications, and any referrals. Every line of treatment must match a procedure the Medical Treatment Guidelines allow without pre-authorization, or the doctor must file a C-4AUTH for treatment outside the guidelines. The MTGs cover the neck, back, shoulder, knee, carpal tunnel, non-acute pain, PTSD, and several other conditions.
The consequence of treating outside the MTGs without a variance is a denied bill. The carrier does not have to pay for care that violates the guidelines, even if the care worked. A common misconception is that “the doctor knows best” overrides the MTGs — the Court of Appeals in Kigin v. State of N.Y. Workers’ Comp. Bd. confirmed that the MTGs bind the medical community as a matter of law.
Section F — Degree of Disability
Section F is the disability rating block. The doctor must check total, marked (75%), moderate (50%), mild (25%), or none, and indicate whether the worker can return to regular duty, modified duty, or no duty. This rating drives the worker’s weekly indemnity check under WCL §15.
The consequence of leaving the disability blank is no indemnity check at all. The carrier pays based on the highest medical rating in evidence, and a blank C-4 produces a zero. A common misconception is that “out of work” alone is enough — the Board needs a percentage, because partial disability and total disability pay different amounts.
A real example: Carlos Rivera, a roofer, broke his wrist. His surgeon wrote “out of work” with no percentage. The carrier paid nothing for three weeks until the surgeon amended the C-4 to “100% total temporary disability.”
Section G — Provider Identification and Signature
Section G captures the provider’s name, WCB authorization number, NPI number, address, phone, and signature with date. The signature is a sworn statement, and a knowingly false C-4 exposes the provider to criminal fraud charges under WCL §114-a(3) and Penal Law felony statutes.
The consequence of a missing authorization number is a rejected bill. The carrier cannot even open the file in its claims system without the number. A common misconception is that a stamped signature is fine — the Board requires a wet or secure electronic signature tied to the named provider, not an office stamp.
Three Real-World Scenarios
These three patterns cover most of the C-4 filings the Board sees in a typical week. Each scenario shows how the same form behaves differently depending on the body part, the cause, and the treatment plan. Use them as templates, not as scripts.
Scenario 1 — Construction Back Injury
Tomas Nowak, a 38-year-old ironworker, lifts a steel beam and feels a pop in his lower back. He goes to an urgent care, then to an orthopedist who files the C-4 within 48 hours.
| Filing Choice on the C-4 | Effect on the Claim |
|---|---|
| ICD-10 M51.26 lumbar disc displacement, MRI ordered | Mid- and Low-Back MTG applies, MRI is pre-authorized |
| Causation marked “yes — direct injury at work” | Claim establishes at first hearing |
| Disability marked 100% total temporary | Carlos receives two-thirds of average weekly wage up to the maximum benefit |
Scenario 2 — Office Carpal Tunnel
Priya Patel, a 45-year-old data analyst, develops numbness in her right hand after a year of heavy keyboard use. Her hand surgeon files a C-4 listing carpal tunnel syndrome as an occupational disease.
| Filing Choice on the C-4 | Effect on the Claim |
|---|---|
| Date of accident = date of disablement, not date of hire | Claim is timely under WCL §28 |
| ICD-10 G56.01 with EMG findings | Carpal Tunnel MTG triggers, surgery is pre-authorized after conservative care |
| Causation tied to repetitive keyboard use | Carrier cannot deny on idiopathic grounds |
Scenario 3 — Motor Vehicle Slip-and-Fall Concussion
Marcus Johnson, a 52-year-old delivery driver, slips on ice exiting his van and hits his head. His neurologist files a C-4 with concussion and post-concussive syndrome.
| Filing Choice on the C-4 | Effect on the Claim |
|---|---|
| ICD-10 S06.0X0A concussion plus F07.81 post-concussive syndrome | Non-Acute Pain and PTSD MTGs both available |
| Disability marked “marked 75%” with no driving | Carrier pays partial benefits, no return to commercial driving |
| C-4AUTH filed for neuropsychological testing | Testing approved under variance rules |
Mistakes to Avoid When Filing the C-4
Each of these mistakes costs money, time, or the entire claim. Treat the list as a pre-flight checklist.
- Filing late. Missing the 48-hour window under WCL §13-a forfeits the bill for that visit and weakens the worker’s record.
- Leaving causation blank. The carrier will controvert the claim, and the Administrative Law Judge cannot establish without a medical opinion.
- Skipping the disability percentage. A blank Section F produces a zero indemnity check until amended.
- Using the wrong employer name. A mismatch with the policy lets the carrier deny under WCL §25.
- Coding only one body part. Missing ICD-10 codes block future C-4AUTH filings for related conditions.
- Treating outside the MTGs without a variance. The bill is denied and the worker can be billed personally, which violates WCL §13-g.
- Using a stamped signature. The Board rejects stamped C-4s as non-conforming.
- Filing a paper C-4 when CMS-1500 is required. The carrier will reject the bill under 12 NYCRR §325-1.3.
- Copy-pasting a prior visit’s narrative. The Board flags identical narratives as potential §114-a fraud.
- Forgetting the WCB authorization number. The bill cannot be processed without it.
- Relying on the worker’s verbal history alone. The doctor must record the mechanism of injury in clinical detail.
Dos and Don’ts for Providers and Workers
These rules apply to every C-4 filing, whether the provider is a solo chiropractor or a hospital system.
Dos
- Do file within 48 hours, because the statute demands it and late filings forfeit the bill.
- Do quote the worker’s own words in the history, because verbatim history defeats credibility attacks.
- Do list every diagnosis, because future authorizations depend on the ICD-10 record.
- Do cite the applicable Medical Treatment Guideline by name, because adjusters approve faster when the citation is explicit.
- Do amend the C-4 promptly when new findings appear, because outdated reports drive wrong indemnity checks.
Don’ts
- Don’t bill the injured worker directly, because WCL §13-g bans balance billing in compensable claims.
- Don’t guess at causation, because a wrong opinion can support a §114-a fraud charge against the worker.
- Don’t use unapproved abbreviations, because the Board’s optical reader rejects non-standard text.
- Don’t mix two patients on one form, because duplicate filings trigger immediate rejection.
- Don’t skip the variance process, because retroactive variances are rarely granted.
Pros and Cons of the C-4 System
The C-4 system has real strengths and real weaknesses, and understanding both helps providers and workers navigate it.
Pros
- The form creates a single, sworn medical record that the Board, carrier, and claimant share.
- The MTG link forces evidence-based care and reduces unnecessary surgery.
- The 48-hour rule pushes early reporting and faster indemnity payment.
- The CMS-1500 transition speeds bill processing for compliant providers.
- The C-4.3 permanent impairment form standardizes loss-of-wage-earning-capacity findings.
Cons
- The form is dense and provider-unfriendly, which deters new authorized providers.
- The MTG variance process is slow and often denies legitimate care.
- Paper-electronic confusion still causes rejected bills four years after the CMS-1500 rollout.
- Disability percentages invite disputes between treating and IME doctors.
- The fee schedule pays below Medicare for some codes, which limits provider participation.
Key Entities You Need to Know
The New York Workers’ Compensation Board is the state agency that adjudicates claims, certifies providers, and publishes the Medical Treatment Guidelines through its main portal. The Chair of the Board sets policy, and the Administrative Law Judges decide individual disputes. The carrier is the workers’ comp insurance company or self-insured employer that pays the bills and indemnity.
The treating provider owns the C-4, and the Independent Medical Examiner files a competing report under 12 NYCRR §300.2. The claimant’s attorney uses the C-4 to argue establishment, classification, and permanency. The Workers’ Compensation Law Judge weighs the C-4 against the IME report and issues a decision, which the parties can appeal to the Board Panel and then to the Appellate Division, Third Department.
Court Rulings That Shape the C-4
The Court of Appeals decision in Kigin v. State of N.Y. Workers’ Comp. Bd. confirmed that the Medical Treatment Guidelines bind treating providers and that variance denials get only limited judicial review. The case forces every C-4 to live inside the MTG framework, and it is the single most important medical-evidence ruling of the last decade.
The Appellate Division decision in Matter of Pompeo v. Auction Direct USA clarified that a treating doctor’s C-4 carries presumptive weight on causation when the IME report is internally inconsistent. The ruling protects workers whose carriers shop for favorable IMEs. Matter of Bland v. Gellman, Brydges & Schroff held that a missing C-4 disability rating cannot be cured by post-hoc testimony alone, which is why Section F must be complete on the day of filing.
How the C-4 Connects to Indemnity Benefits
The C-4 disability rating drives the worker’s weekly check under WCL §15(5). A total temporary rating pays two-thirds of the average weekly wage up to the statutory maximum, which the Board updates each July under the maximum benefit schedule. A moderate (50%) rating pays half of that amount, and a mild (25%) rating pays a quarter.
The consequence of a flip-flopping disability rating is uneven indemnity. If the doctor writes 100% on one C-4 and 50% on the next without explaining why, the carrier can reduce benefits unilaterally and force the claimant to litigate. A common misconception is that the Board sets the rating — the treating doctor sets it on the C-4, and the Judge resolves disputes between competing ratings.
How the C-4 Connects to Medical Bills
The CMS-1500 bill and the C-4 narrative travel together through the Board’s eClaims XML system. The carrier has 45 days under 12 NYCRR §325-1.25 to pay, object, or request additional information. Silence past 45 days waives most objections.
The consequence of an incomplete C-4 is a bill objection that resets the clock. Providers who do not respond to objections within the statutory window lose the bill permanently. A common misconception is that the worker is responsible for unpaid bills — the worker is not, and any provider who tries to collect from the worker violates WCL §13-g.
How the C-4 Connects to Permanency
When the worker reaches maximum medical improvement, the treating provider files a C-4.3 Doctor’s Report of MMI/Permanent Impairment instead of another C-4. The C-4.3 ranks the worker’s loss of wage-earning capacity and any schedule loss of use under the 2018 Permanency Guidelines. The C-4.3 controls how many weeks of post-MMI benefits the worker receives.
The consequence of a sloppy C-4.3 is a low classification and lost lifetime benefits. A worker with a 75% loss who is classified at 50% loses years of indemnity. A common misconception is that the C-4.3 is optional — once MMI is reached, WCL §15(3) requires a permanency opinion, and the case cannot close cleanly without one.
Frequently Asked Questions
Is Form C-4 still used in 2026?
Yes. The paper C-4 still exists for limited filings, but most authorized providers now file the CMS-1500 plus narrative through the Board’s eClaims gateway, which captures the same data the paper C-4 captured.
Can an injured worker fill out the C-4?
No. Only a WCB-authorized treating provider may sign and file the C-4, because the form contains a sworn medical opinion that the worker is not licensed to give.
How fast must the C-4 be filed?
Yes, speed matters — Workers’ Compensation Law §13-a requires filing within 48 hours of the first treatment, and late filing forfeits the bill for that visit.
Can a chiropractor file a C-4?
Yes. Chiropractors, podiatrists, dentists, psychologists, nurse practitioners, and physician assistants who hold WCB authorization may all file the C-4 within their scope of practice.
Does an emergency room visit count as a C-4?
No. Hospital records are not C-4 substitutes, because they lack the disability rating and causation opinion the Board requires for indemnity decisions.
Can the C-4 be amended after filing?
Yes. Providers may file an amended C-4 or a follow-up C-4.2 to correct errors, update findings, or change the disability rating, and amendments are common.
Will the worker pay if the carrier denies the C-4 bill?
No. Workers’ Compensation Law §13-g bans balance billing in compensable claims, and providers who pursue the worker can lose authorization.
Is a stamped signature acceptable on the C-4?
No. The Board requires a wet signature or a secure electronic signature tied to the named provider, and stamped forms are rejected as non-conforming.
Can an out-of-state doctor file a C-4?
Yes, but only with prior out-of-state authorization from the Board, which is granted in narrow situations like border-state residence or travel-related injuries.
Does the C-4 establish the claim by itself?
No. The C-4 supplies the medical proof, but the worker must also file a C-3 employee claim form and the Board must hold a hearing or issue a proposed decision to establish the case.
Can a carrier ignore the C-4?
No. The carrier must respond within 45 days under 12 NYCRR §325-1.25, and silence past that window waives most billing objections under New York law.
What replaces the C-4 at maximum medical improvement?
Yes, the C-4.3 replaces the C-4 at MMI, and it ranks loss of wage-earning capacity and schedule loss of use under the 2018 Permanency Guidelines.
Related reading
- How to Fill Out New York Form C-3 (w/Examples) + FAQs
- How to Fill Out New York Form C-4.2 (w/Examples) + FAQs
- How to Fill Out New York Form C-4.3 (w/Examples) + FAQs
- How to Fill Out New York Form DB-271S (w/Examples) + FAQs
- How to Fill Out New York Form RFA-2 (w/Examples) + FAQs
- How to Fill Out New York Form WCB MG-2 (w/Examples) + FAQs
- How to Fill Out California WCAB DWC-AD 1 (w/Examples) + FAQs