ANSI X12 837P - 4010 2300 PWK - Claim Supplemental Information

Image Description

August 06, 2025

The PWK (Paperwork) segment in the 2300 loop of the X12 837 (4010) professional claim is used to indicate that additional documentation is being submitted or is available to support the healthcare claim. This segment links the claim to attachments such as medical records, operative notes, or consent forms.

The PWK segment is situational and should only be reported when required by the payer or trading partner. Providers should always confirm with the payer if attachments are necessary and follow their required submission process.

Sample 837P (4010) – 2300 PWK Segment

> Claim Supplemental Information (2300) PWK*OB*FX***AC*ACD123~

In the example PWK*OB*FX***AC*ACD123~:

  • OB – Report Type Code indicating an Operative Note.
  • FX – Report Transmission Code indicating the documentation was sent by fax.
  • PWK03–PWK04 – Not used in this example.
  • AC – Identification Code Qualifier, meaning the following value is an Attachment Control Number.
  • ACD123 – The control number associated with the faxed document.

Reminder: Confirm with the payer if the attachment is required and how the control number should be referenced. Payer rules may vary under the 4010 implementation.

HIPAA Guide – 837P [4010]

[Situational]

Segment Field Name Definition
PWK 01 Report Type Code
[Attachment Report Type Code]
CodeDefinition
77Support Data for Verification
Referral (completed referral form)
ASAdmission Summary
B2Prescription
B3Physician Order
B4Referral Form
CTCertification
DADental Models
DGDiagnostic Report
DSDischarge Summary
EBExplanation of Benefits (Coordination of Benefits or Medicare Secondary Payor)
MTModels
NNNursing Notes
OBOperative Note
OZSupport Data for Claim
PNPhysical Therapy Notes
POProsthetics or Orthotic Certification
PZPhysical Therapy Certification
RBRadiology Films
RRRadiology Reports
RTReport of Tests and Analysis Report
PWK 02 Report Transmission Code
[Attachment Transmission Method]
CodeDefinition
AAAvailable on Request at Provider Site
BMBy Mail
ELElectronically Only
EME-Mail
FXBy Fax
PWK 03 Report Copies Needed Not used.
PWK 04 Entity Identifier Code Not used.
PWK 05 Identification Code Qualifier
CodeDefinition
ACAttachment Control Number
PWK 06 Identification Code
[Attachment Control Number]
PWK 07 Description Not used.
PWK 08 Actions Indicated Not used.
PWK 09 Request Category Code Not used.

Note: The PWK segment should not be included unless documentation is required. Be sure to follow payer-specific guidance on submission formats and control number usage.

We hope you found this article helpful! Please reach out to us with questions/feedback.

See more articles