Pennsylvania Form LIBC-336, the Notice of Compensation Denial, is the official document an employer or its workers’ compensation insurance carrier files with the Pennsylvania Bureau of Workers’ Compensation to formally reject all or part of an injured worker’s claim under the Pennsylvania Workers’ Compensation Act. The form must be issued and served within 21 days of the employer’s notice or knowledge of the alleged injury, a deadline anchored in Section 406.1 of the Act.
Filing LIBC-336 incorrectly, late, or in bad faith exposes the employer to attorney fees, unreasonable-contest penalties, and Yellow Freight liability under Yellow Freight Systems v. WCAB. Pennsylvania employers file roughly 175,000 work injury reports each year, and the Bureau’s Annual Report shows that nearly one in three claims is denied — making LIBC-336 one of the most consequential forms in PA workers’ comp practice.
- 📝 How to complete every box on the current revision of LIBC-336 line by line
- ⚖️ Which statutory denial reasons under Section 406.1 survive litigation and which trigger penalties
- 🖥️ How to file through the WCAIS portal, by EDI, and on paper with the Bureau
- 🧾 Three full filled-out scenarios — a no-injury denial, a no-disability denial, and a late-notice denial
- 🚫 The ten field-level mistakes adjusters make most and the exact consequence of each
What the Form Is and Who Must File It
The Notice of Compensation Denial is the form used to tell an injured worker, in writing and on the record, that the employer or its insurer will not pay workers’ compensation benefits for a reported injury. It is the statutory counterpart to the LIBC-495 Notice of Temporary Compensation Payable and the LIBC-501 Notice of Compensation Payable, both of which accept a claim. Where LIBC-501 says yes, LIBC-336 says no, and that single answer drives every downstream litigation step in front of a Workers’ Compensation Judge.
The party who must file LIBC-336 is the employer through its insurance carrier, third-party administrator, or self-insured claims unit. The injured worker never files this form — the worker receives it. Defense attorneys at firms such as Marshall Dennehey, Chartwell Law, and Weber Gallagher often draft or review the denial before the adjuster transmits it through the Workers’ Compensation Automation and Integration System (WCAIS). The statute that requires the form is Section 406.1 of the Pennsylvania Workers’ Compensation Act, and the regulation that governs its content sits at 34 Pa. Code § 121.17.
The consequence of not filing is severe. If an employer fails to issue an LIBC-336, an LIBC-501, an LIBC-495, or an LIBC-502 within 21 days, the Bureau treats the claim as unresolved and the employer loses the ability to control medical treatment under Section 306(f.1). A common misconception is that silence equals denial — it does not. Silence equals exposure.
Before You Start: Documents and Information You Need
Pulling LIBC-336 together is a documentation exercise, not a writing exercise. Adjusters who open the form before gathering the underlying records routinely miss the 21-day deadline because they pause mid-draft to hunt for an address or a wage figure. The Bureau’s Claims Information page lists the universe of records employers should keep in the claim file, and the items below are the non-negotiable inputs for a defensible denial.
- First Report of Injury (LIBC-344 FROI/EDI). You need the exact date of injury, body part, and mechanism that was originally reported so the denial matches the worker’s allegation. Mismatches between the FROI and the denial are the single most common ground for an unreasonable-contest fee under Kuemmerle v. WCAB.
- Employee’s full legal name, Social Security number, and current mailing address. The Bureau cross-checks SSNs against EDI feeds; a wrong digit causes the denial to fail to post in WCAIS.
- Employer’s UC account number and FEIN. Without these the carrier cannot route the denial to the correct employer file.
- Insurance carrier code and policy number. The carrier code is the four-digit NAIC-derived code the Bureau assigns; missing it kicks the filing back.
- Average Weekly Wage (AWW) calculation worksheet. Even a denial requires the AWW because the worker can later prove entitlement, and the AWW anchors any retroactive award.
- Date the employer received notice of the injury. This is the trigger for the 21-day clock under Section 406.1.
- Medical records or IME report supporting the denial reason. Denials based on “no work-related injury” without a medical opinion invite penalties under Waldameer Park v. WCAB (Morrison).
- Witness statements and supervisor reports. These support course-and-scope and notice defenses.
- Counsel of record for the claimant, if represented. If the worker has a lawyer, the denial must be served on counsel as well.
- Prior LIBC-495 (TNCP), if one was issued. A TNCP that ripened into a denial must be revoked using both LIBC-336 and LIBC-502 (Notice Stopping Temporary Compensation).
Where to Get the Form and How to Access It
The only official source for LIBC-336 is the Pennsylvania Department of Labor & Industry. The current revision lives on the Workers’ Compensation Publications page, and the file name follows the pattern LIBC-336.pdf. Always confirm the revision date printed in the bottom-left corner of the form — using a superseded version is a frequent reason WCAIS rejects a filing.
Insurance carriers and third-party administrators rarely fill the PDF by hand. Instead, they generate the denial through their claims platform (Origami, Riskonnect, ClaimCenter, or an internal system) and transmit it as an EDI Release 3.1 SROI transaction with a code of “04” (Denial). The EDI feed automatically populates the matching LIBC-336 in WCAIS, which then serves the worker.
Self-insured employers and small carriers without EDI capability can complete LIBC-336 directly inside WCAIS by logging in, opening the claim, and selecting Create Bureau Document. Paper filings are still accepted, but the Bureau strongly prefers electronic submission. A misconception worth correcting: downloading the form from a third-party legal blog is risky because those copies are often years out of date. Pull it from the official Department of Labor & Industry page every time.
Step-by-Step: How to Fill Out LIBC-336 Line by Line
The form is one page, but every box matters. The Bureau organizes it into an Employer/Insurer Information block at the top, an Employee Information block, a Claim Information block, the Reason for Denial block, and the Signature and Verification block at the bottom. Each H3 below walks through one field, in the order it appears on the current revision.
Employer Name
The field asks for the legal name of the employer where the alleged injury occurred. Write the name exactly as it appears on the UC-2 quarterly filings and the insurance policy declarations page, in upper-case letters. For example, Maria Lopez, an adjuster at Liberty Mutual, writes ACME LOGISTICS LLC — not “Acme” and not the d/b/a. If the employer operates under a trade name, enter the registered legal entity and put the d/b/a in parentheses, like ACME LOGISTICS LLC (DBA ACME EXPRESS). A common mistake is entering the parent company instead of the subsidiary that actually employs the worker; the consequence is that the Bureau cannot match the denial to the correct policy and the filing fails to post. The misconception here is that the trade name is enough — it never is, because the PA Department of State business registry keys off the legal entity.
Employer Address
Enter the street address of the employer location where the worker was assigned at the time of injury, not the corporate headquarters. Use the format 123 MAIN STREET, SUITE 200, ALLENTOWN, PA 18101. If the worker was a traveling employee, enter the address of the home terminal. Janet Reyes, an HR director at a regional trucking company, enters the Allentown terminal address rather than the Dallas headquarters because Janet’s driver was dispatched out of Allentown. The edge case to watch is remote workers: use the address of the office to which the remote worker reports, not the worker’s home, unless the home is the designated work location in writing. The mistake of entering the corporate HQ address sends Bureau correspondence to the wrong office and delays the worker’s mailings. The misconception is that any company address will do — the address controls venue for any future Workers’ Compensation Judge hearing.
Employer FEIN
This box asks for the nine-digit Federal Employer Identification Number. Enter it as 12-3456789 with the dash, exactly as it appears on the employer’s IRS Form SS-4 confirmation letter. Marcus Chen, an adjuster, copies the FEIN from the policy declarations page rather than asking the employer, because employer-provided FEINs are wrong roughly 8% of the time. If the employer is part of a controlled group, use the FEIN of the entity on the workers’ compensation policy, not the parent’s FEIN. The common mistake is transposing two digits — the consequence is that WCAIS will accept the filing but the Bureau’s analytics will not link the denial to the employer’s loss-run history. The misconception is that the FEIN is interchangeable with the UC account number; the UC account number is a separate seven-digit identifier issued by the PA Office of UC Tax Services.
Insurance Carrier Name and Code
Enter the legal name of the workers’ compensation carrier and the four-digit Bureau carrier code. The carrier code list is maintained by the PA Insurance Department and the Bureau, and every licensed carrier has one. Aisha Bennett, a TPA adjuster for Sedgwick on behalf of Travelers, enters TRAVELERS PROPERTY CASUALTY CO OF AMERICA and the code printed on the policy. If the employer is self-insured, enter SELF-INSURED in the carrier name field and the Bureau’s self-insurance code. The frequent mistake is leaving the carrier code blank because the adjuster cannot find it; the consequence is automatic rejection in WCAIS. The misconception is that the NAIC number is the same as the Bureau carrier code — they are not, although the Bureau code is often derived from the NAIC.
Policy Number and Policy Period
Enter the workers’ compensation policy number exactly as it appears on the declarations page, including any letter prefixes, and the policy period in MM/DD/YYYY format. Carlos Mendez, an adjuster at AmTrust, enters WC1234567 and the policy period 01/01/2026 to 01/01/2027. The edge case is mid-term cancellations or short-rate policies — use the policy in effect on the date of injury, not the policy in effect on the date of denial. The mistake of using the renewal policy instead of the in-force policy at injury triggers a coverage dispute that can land the carrier in front of the Pennsylvania Workers’ Compensation Security Fund. The misconception is that any in-force policy will do — only the policy on the date of injury controls.
Employee Full Legal Name
Enter the worker’s full legal name as it appears on the worker’s Social Security card, last name first. Maria Lopez enters RIVERA, LUIS A. for a claimant whose card reads Luis Antonio Rivera. The edge case is hyphenated last names and suffixes: include them exactly as written on the card. The mistake of entering a nickname (e.g., Tony instead of Antonio) breaks the SSA cross-match and the denial may fail to serve correctly. The misconception is that the name on the I-9 controls — it does not. The Social Security card controls because the Bureau’s claim file keys to the SSN-name pair held by the Social Security Administration.
Employee Social Security Number
Enter the worker’s nine-digit SSN with dashes, as 123-45-6789. If the worker has only an ITIN, enter the ITIN and check the box on the form indicating no SSN was provided; Pennsylvania permits undocumented workers to receive benefits under Reinforced Earth Co. v. WCAB (Astudillo). The frequent mistake is using the SSN listed on the employer’s I-9 instead of the SSN the worker has since corrected with HR; the consequence is that the denial posts under a phantom claim. The misconception is that the SSN is optional — it is not, and a missing SSN without an ITIN substitute will cause WCAIS to bounce the filing.
Employee Mailing Address
Enter the worker’s current mailing address, not the address on file at the time of hire. Adjusters should verify the address by calling the worker or checking the most recent USPS National Change of Address feed before filing. Janet Reyes learns that her claimant moved after the injury and enters the new address, 45 OAK LANE, READING, PA 19601. The edge case is workers who have moved out of state — still enter the new out-of-state address, because Pennsylvania jurisdiction is fixed by the place of injury, not the worker’s residence. The mistake of mailing the denial to a stale address starts a service dispute that can extend the 21-day deadline for filing a Claim Petition. The misconception is that the worker’s pre-injury address is “good enough” — it is not, because the Pennsylvania Rules of Civil Procedure on service require service at the last known address.
Date of Injury
Enter the date the worker alleges the injury occurred, in MM/DD/YYYY format. For repetitive-trauma or cumulative-trauma claims, enter the last date of exposure as the date of injury, consistent with the injury date rule in Section 301(c)(2). Aisha Bennett enters 03/14/2026 for a single-event back strain and 02/28/2026 (the last day worked) for a carpal tunnel cumulative trauma. The mistake is using the date the worker reported the injury instead of the date the injury occurred; the consequence is that course-and-scope and notice defenses are evaluated against the wrong date. The misconception is that “date of injury” means “date of diagnosis” — for occupational disease claims it can, but for traumatic injuries it means the date of the event.
Date Employer Was Notified
Enter the date the employer first received notice of the injury, in MM/DD/YYYY format. This box drives the 21-day clock under Section 406.1. Marcus Chen writes 03/16/2026 because the supervisor’s incident report is timestamped that morning, even though the worker did not file the formal claim until a week later. The edge case is constructive notice — if a supervisor witnessed the injury, the date of the event is the date of notice. The mistake of using the date the carrier received the FROI from the employer instead of the date the employer learned of the injury restarts the 21-day clock incorrectly and can make a timely denial look untimely. The misconception is that notice runs from the worker’s filing of a Claim Petition — it does not; notice runs from the employer’s earliest awareness.
Description of Injury
Enter a one-sentence description that mirrors the worker’s allegation, not the carrier’s view. Use plain language: Claimant alleges low-back strain while lifting a 60-pound box on 03/14/2026 at the Allentown warehouse. Carlos Mendez avoids editorializing because the carrier’s position belongs in the Reason for Denial block, not here. The edge case is multi-body-part claims — list every body part the worker alleged, because failing to list a body part may waive the denial as to that part under Cinram Manufacturing v. WCAB (Hill). The mistake of narrowing the alleged injury to what the carrier accepts produces a partial-denial trap. The misconception is that minimizing the description protects the carrier — it does not; it creates litigation risk.
Average Weekly Wage
Even on a denial, compute the AWW under Section 309 and enter it in dollars and cents. Maria Lopez calculates the AWW using the highest three of the four quarters preceding injury and writes $1,142.86. The edge case is workers with less than a year of employment — use the actual earnings under Section 309(d.2). The mistake of leaving the AWW blank “because it’s denied anyway” is the single most common Bureau rejection reason. The misconception is that the AWW is irrelevant on a denial — it is not, because it pre-stages the compensation rate if a Workers’ Compensation Judge later grants the claim.
Reason for Denial — Checkbox Block
This is the most contested block on the form. The current revision lists statutory reasons including: the employee did not suffer a work-related injury, the employee is not disabled as a result of a work-related injury, although an injury took place the employee is able to return to work without loss of earnings, the employee did not give notice within 120 days, the claim was not filed within the statute of limitations, the employee is not an employee, and Other. Aisha Bennett checks only the boxes she can support with evidence in the claim file on the date of filing. The edge case is mixed reasons — if the medical evidence supports both “no injury” and “no disability,” check both, because Sloan v. WCAB allows alternative pleading. The mistake of checking every box “just in case” is the textbook unreasonable contest under Waldameer Park v. WCAB (Morrison), exposing the employer to attorney fees. The misconception is that checking Other without explanation is enough — Other requires a written, specific basis on the form or in an attached page.
“Other” Reason Narrative
If you checked Other, type a precise one- to two-sentence narrative grounded in the record. Marcus Chen writes Claimant was an independent contractor under the ABC test in Section 4(a) and not an employee subject to the Act. The edge case is intoxication defenses under Section 301(a) — list the defense by statutory subsection. The mistake of writing a vague “investigation continues” is treated as no reason at all and converts the denial into a de facto acceptance under the bureau’s Yellow Freight line of cases. The misconception is that Other is a catch-all — judges read it strictly.
Signature of Insurer’s Representative
The adjuster or authorized representative signs in this block, prints their name, lists their title, and dates the form. Carlos Mendez signs Carlos Mendez, prints CARLOS MENDEZ, lists SENIOR CLAIMS EXAMINER, AMTRUST NORTH AMERICA, and dates 04/04/2026. The edge case is electronic signatures through WCAIS — the system applies the user’s e-signature automatically and the date is system-generated. The mistake of leaving the signature block blank is fatal: an unsigned LIBC-336 is a nullity, and the denial is treated as never having been filed. The misconception is that a paralegal or assistant can sign — only an authorized representative of the insurer or self-insured employer may sign, per 34 Pa. Code § 121.17.
Date of Filing and Service
Enter the date the denial is filed with the Bureau and served on the worker. The two dates should be the same, and both should be inside the 21-day window. Janet Reyes files and serves on 04/05/2026, with notice received on 03/16/2026 — comfortably inside 21 days. The edge case is when the 21st day falls on a weekend or holiday: under 1 Pa. Code § 31.12, the deadline rolls to the next business day. The mistake of filing on day 22 because “the system was down” is not a defense and triggers a late-filing penalty under Section 435. The misconception is that filing on day 21 is safe even if service happens on day 25 — both filing and service must occur within 21 days.
Three Filled-Out Examples Using Real Scenarios
The three scenarios below cover the most common LIBC-336 fact patterns. Each follows one named adjuster through the form.
Scenario 1 — No Work-Related Injury (Maria Lopez at Liberty Mutual)
Maria denies a back-strain claim because the IME report concludes the disc bulge is degenerative and not caused by the alleged lifting incident.
| Form Section | What Maria Enters |
|---|---|
| Employer Name | ACME LOGISTICS LLC |
| Employer FEIN | 12-3456789 |
| Insurance Carrier | LIBERTY INSURANCE CORPORATION (carrier code on file) |
| Employee Name | RIVERA, LUIS A. |
| Employee SSN | 123-45-6789 |
| Date of Injury | 03/14/2026 |
| Date Employer Notified | 03/16/2026 |
| Description of Injury | Claimant alleges low-back strain while lifting a 60-pound box. |
| Average Weekly Wage | $1,142.86 |
| Reason for Denial | The employee did not suffer a work-related injury |
| Signature / Date | Maria Lopez, Senior Adjuster — 04/04/2026 |
Scenario 2 — No Disability Although Injury Occurred (Aisha Bennett at Sedgwick/Travelers)
Aisha concedes a minor wrist contusion but denies wage-loss benefits because the treating doctor released the worker to full duty without restriction the next day.
| Form Section | What Aisha Enters |
|---|---|
| Employer Name | PENN VALLEY MANUFACTURING INC |
| Employer FEIN | 45-6789012 |
| Insurance Carrier | TRAVELERS PROPERTY CASUALTY CO OF AMERICA |
| Employee Name | KIM, SOO-YOUNG |
| Employee SSN | 234-56-7890 |
| Date of Injury | 02/10/2026 |
| Date Employer Notified | 02/10/2026 |
| Description of Injury | Right wrist contusion from machine guard impact. |
| Average Weekly Wage | $986.50 |
| Reason for Denial | Although an injury took place, the employee is able to return to work without loss of earnings |
| Signature / Date | Aisha Bennett, Claims Examiner — 02/26/2026 |
Scenario 3 — Late Notice Beyond 120 Days (Marcus Chen at AmTrust)
Marcus denies because the worker reported the alleged shoulder injury 161 days after the event, beyond the 120-day notice bar in Section 311 of the Act.
| Form Section | What Marcus Enters |
|---|---|
| Employer Name | KEYSTONE ROOFING CO |
| Employer FEIN | 78-9012345 |
| Insurance Carrier | AMTRUST NORTH AMERICA |
| Employee Name | O’BRIEN, PATRICK J. |
| Employee SSN | 345-67-8901 |
| Date of Injury | 10/05/2025 |
| Date Employer Notified | 03/15/2026 |
| Description of Injury | Right shoulder rotator-cuff tear allegedly from roofing fall. |
| Average Weekly Wage | $1,420.00 |
| Reason for Denial | The employee did not give notice within 120 days as required by Section 311 |
| Signature / Date | Marcus Chen, Senior Claims Examiner — 04/04/2026 |
How to File the Completed Form
LIBC-336 can be filed through three channels, and the Bureau accepts all of them, but the speed, cost, and proof-of-filing differ dramatically.
The preferred channel is electronic filing through WCAIS. Log in with your carrier or self-insured credentials, open the claim, select Create Bureau Document, choose LIBC-336 Notice of Compensation Denial, complete each field, attach any supporting documents (IME report, witness statements), and submit. There is no filing fee. WCAIS issues a confirmation number and timestamp immediately, and that confirmation is your proof of filing; keep it in the claim file. Processing is instantaneous — the worker and any counsel of record are served by mail and email through WCAIS the same business day.
The second channel is EDI Release 3.1 SROI submission, used by virtually every large carrier. The transaction code for a denial is 04, and the carrier’s TPA or claims platform pushes the SROI through the Bureau’s EDI clearinghouse. The accepted payment method question does not apply because there is no fee. Processing time is generally within 24 hours, and the proof-of-filing is the EDI acknowledgment (“AK”) return code; TA means accepted, TR means rejected. Keep both the original SROI and the AK in the claim file.
The third channel is paper filing. Mail the completed LIBC-336 to the Pennsylvania Bureau of Workers’ Compensation, 1171 South Cameron Street, Room 324, Harrisburg, PA 17104-2501, with a separate copy served on the worker by first-class mail at the address on the form. There is no filing fee. Processing takes 5 to 10 business days, and the proof-of-filing is a USPS Certificate of Mailing or Certified Mail return receipt — get one for every paper filing because without it the Bureau cannot reconstruct the service date.
What Happens After You File
Once the denial posts, the worker has three years from the date of injury — under Section 315 of the Act — to file a Claim Petition contesting the denial. The Claim Petition is filed in WCAIS using LIBC-362, and the Bureau assigns the case to a Workers’ Compensation Judge by venue, typically the venue of the employer’s address listed on the LIBC-336.
The first hearing is usually a mandatory mediation under 34 Pa. Code § 131.59, followed by evidentiary hearings. The carrier bears the burden on affirmative defenses (notice, statute of limitations, intoxication), and the worker bears the burden on the elements of a compensable injury. If the judge later grants the Claim Petition, the carrier owes retroactive benefits from the date of disability plus 10% statutory interest under Section 406.1(a).
Bad-faith denials draw fee shifting under Section 440 and the Waldameer Park line of cases. The misconception that a denial “ends the file” is exactly backwards — a denial opens the litigation file.
Mistakes to Avoid When Filling Out the Form
Field-level errors on LIBC-336 are the leading cause of penalties in Pennsylvania workers’ comp practice. The list below covers the ten most common.
- Filing the denial after the 21-day deadline — the carrier loses control of medical treatment and faces a Section 435 penalty.
- Checking every reason-for-denial box without record support — the judge will find unreasonable contest and award attorney fees under Waldameer Park.
- Leaving the Average Weekly Wage blank — WCAIS rejects the filing and the carrier has to refile, often blowing the 21-day window.
- Using a stale employee address — service is defective and the worker may obtain default-style relief.
- Entering the parent company instead of the subsidiary employer — the Bureau cannot match the denial to the correct policy.
- Using the wrong policy period — coverage disputes arise and the matter can be referred to the Workers’ Compensation Security Fund.
- Failing to attach the IME report when denying on medical grounds — the carrier loses credibility at the first hearing.
- Writing “investigation continues” under Other — judges treat this as no reason at all.
- Forgetting to revoke a prior LIBC-495 — the TNCP can convert to a full NCP by operation of law under Section 406.1(d)(6).
- Missing the signature block — an unsigned LIBC-336 is a legal nullity.
- Failing to serve counsel of record — the appeal clock may not start until proper service occurs.
- Using a superseded revision of the form — WCAIS may accept it but defense counsel and judges will flag it.
Do’s and Don’ts
A short list of best practices keeps adjusters and defense counsel out of trouble.
- Do file through WCAIS whenever possible — the timestamp is your best proof of filing.
- Do calendar the 21-day deadline the day the FROI hits your desk and set a 7-day pre-deadline alert.
- Do attach the medical opinion supporting a “no injury” or “no disability” denial as a contemporaneous record.
- Do verify the worker’s current address by phone or NCOA before filing.
- Do coordinate with defense counsel before checking Other — the wording will be litigated.
- Do save the WCAIS confirmation number and EDI AK code in the claim file the same day.
- Don’t check reason-for-denial boxes you cannot prove today — alternative pleading is fine, but unreasonable contest is not.
- Don’t write narrative editorials in the Description of Injury — mirror the allegation, not your defense.
- Don’t use a draft IME or unsigned medical narrative as the basis for denial.
- Don’t rely on the employer’s I-9 SSN — always confirm against the Social Security card or W-2.
- Don’t file by paper if you can file by WCAIS — the 5-to-10-day paper lag eats into your deadline window.
- Don’t serve only the worker if counsel of record exists — serve both.
Pros and Cons of Filing on Your Own vs. With Defense Counsel
Many adjusters can complete LIBC-336 without involving defense counsel, but the calculus changes with claim complexity.
- Pro of solo filing — speed; the adjuster controls the deadline directly.
- Pro of solo filing — cost; no legal fees for a routine denial.
- Pro of solo filing — institutional knowledge; veteran adjusters know the form cold.
- Pro of solo filing — confidentiality; fewer hands on the claim file.
- Pro of solo filing — consistency; the adjuster’s claims platform autopopulates standard fields.
- Con of solo filing — Other narratives often invite penalties without counsel’s eye.
- Con of solo filing — multi-body-part denials require legal nuance most adjusters lack.
- Con of solo filing — coverage disputes and ABC-test independent-contractor denials are legal calls.
- Con of solo filing — bad-faith risk under Waldameer Park is hard to spot without counsel.
- Con of solo filing — appellate exposure if the denial is later challenged before the Workers’ Compensation Appeal Board.
LIBC-336 vs. LIBC-344 (Medical-Only Denial)
A frequent point of confusion is whether to use LIBC-336 or LIBC-344. The table below compares them at a glance.
| Dimension | LIBC-336 vs. LIBC-344 |
|---|---|
| Purpose | LIBC-336 denies the entire claim; LIBC-344 acknowledges a medical-only event without admitting indemnity liability. |
| Triggering scenario | LIBC-336 is used when the carrier rejects compensability; LIBC-344 is used when there’s no wage loss and only medical bills are at issue. |
| Statutory basis | LIBC-336 under Section 406.1; LIBC-344 under Section 406.1(d.1). |
| Effect on wage-loss benefits | LIBC-336 denies wage-loss benefits; LIBC-344 does not address them because none are claimed. |
| Conversion risk | LIBC-336 does not auto-convert; LIBC-344 must be carefully drafted to avoid implied acceptance under Armstrong v. WCAB. |
FAQs
Is LIBC-336 the same as a “Notice of Workers’ Compensation Denial”?
Yes. LIBC-336 is the Bureau’s form number for the Notice of Compensation Denial; the two terms refer to the same document used by employers and carriers to reject a claim.
Can the injured worker file LIBC-336?
No. Only the employer or its insurance carrier files LIBC-336. The injured worker receives it and may contest it by filing a Claim Petition (LIBC-362) within three years.
Does the 21-day clock run from the date of injury or the date of notice?
No, it does not run from the date of injury. It runs from the date the employer first received notice or knowledge of the alleged injury under Section 406.1 of the Act.
Do I write the worker’s nickname in the Employee Name box?
No. Always use the worker’s full legal name as printed on the Social Security card; nicknames break the SSA cross-match and can cause service failures.
Can I leave the Average Weekly Wage blank on a denial?
No. WCAIS will reject a denial that lacks an AWW, even though no benefits are being paid; the AWW is required for the file’s integrity.
Do I have to check only one Reason for Denial box?
No. You may check more than one box if each is supported by record evidence, but checking unsupported boxes invites unreasonable-contest fees.
Is electronic filing through WCAIS mandatory?
No, paper filing is still allowed, but WCAIS is strongly preferred because it timestamps the denial and serves the worker the same day.
Does the Other box require a written explanation?
Yes. A bare check on Other without a specific statutory or factual basis is treated as no reason at all and may convert the denial into an acceptance.
Can I deny a claim filed by an undocumented worker?
Yes, but only on the merits — immigration status alone is not a defense under Reinforced Earth Co. v. WCAB (Astudillo), and using it as a reason can trigger penalties.
Do I need to issue a separate LIBC-502 if I previously issued a TNCP?
Yes. When revoking a Temporary Notice of Compensation Payable, you must issue LIBC-502 and LIBC-336 together within the 90-day TNCP window.
Is the Date Employer Notified box the same as the date the carrier learned of the claim?
No. It is the date the employer received notice; the carrier’s later receipt date does not extend the 21-day deadline.
Can a paralegal sign LIBC-336 on behalf of the adjuster?
No. Only an authorized representative of the insurer or self-insured employer may sign, per 34 Pa. Code § 121.17; paralegal signatures are not valid.
Does filing LIBC-336 stop medical bills from being owed?
Yes, as to the denied claim, the carrier is not obligated to pay medical bills; if the claim is later granted, the carrier owes the bills retroactively with 10% interest.
Is there a filing fee for LIBC-336?
No. The Bureau charges no fee for filing LIBC-336 through any channel — WCAIS, EDI, or paper.
Related reading
- How to Fill Out Pennsylvania Form LIBC-337 (w/Examples) + FAQs
- How to Fill Out Pennsylvania Form LIBC-344 (w/Examples) + FAQs
- How to Fill Out Pennsylvania Form LIBC-501 (w/Examples) + FAQs
- How to Fill Out Pennsylvania Form LIBC-378 (w/Examples) + FAQs
- How to Fill Out Pennsylvania Form LIBC-410 (w/Examples) + FAQs
- How to Fill Out Pennsylvania Form LIBC-757 (w/Examples) + FAQs