Acknowledgment codes

The codes inside the acknowledgment segments — TA1, AK9, IK3/IK4, STC. Most operational debugging starts with finding one of these and looking it up here.

TA1 — interchange acknowledgment

Element	Code	Meaning
TA101	(echoes ISA13)	The interchange control number being acknowledged.
TA104	A	Accepted. The interchange parsed; functional acks may follow.
TA104	E	Accepted with errors. Continue processing; check TA105 for the issue.
TA104	R	Rejected. The interchange did not parse. Look at TA105.

TA105 interchange note codes (most common)

Code	Meaning	Likely cause
000	No error	(informational E only)
001	Interchange Control Number does not match value in TA101	Misalignment between ISA13 and IEA02
002	Standards version not supported	Wrong ISA12
003	Sender or Receiver ID not authorized	ISA06/ISA08 mismatch with partner
005	Invalid Interchange ID Qualifier	ISA05/ISA07 wrong
017	Invalid sender / receiver	Wrong IDs for this trading partner
024	Invalid Interchange Content	Trailer/segment-counter mismatch
025	Duplicate Interchange Control Number	Replay sent with stale ISA13

999 — functional acknowledgment

The 999 reports on one or more functional groups inside the interchange. It replaces the legacy 997 and adds element-level error reporting.

AK9 — group-level response

Element	Code	Meaning
AK901	A	Accepted
AK901	P	Partially Accepted (some transactions failed)
AK901	E	Accepted but errors were noted
AK901	R	Rejected

IK3 — segment-level error

IK301 segment ID, IK302 segment position in transaction, IK304 error code.

IK304	Meaning
1	Unrecognized segment ID
2	Unexpected segment
3	Required segment missing
4	Loop occurs over maximum times
5	Segment exceeds maximum use
6	Segment not in defined transaction set
7	Segment not in proper sequence
8	Segment has data element errors (look at the following IK4)
I6	Implementation segment requirement not met
I7	Implementation loop occurs under minimum times
I8	Implementation segment below minimum use

IK4 — element-level error

IK401 reference (sub-element position), IK403 error code, IK404 data value (truncated).

IK403	Meaning
1	Required data element missing
2	Conditional required data element missing
3	Too many data elements
4	Data element too short
5	Data element too long
6	Invalid character in data element
7	Invalid code value
8	Invalid date
9	Invalid time
10	Exclusion condition violated
12	Too many repetitions
13	Too many components
I6	Implementation invalid code value
I9	Implementation dependent data element missing
I10	Implementation too few repetitions

277CA — claim acknowledgment

The 277CA carries per-claim status decisions in the STC segment.

STC01 — composite status

STC01 is a composite of three sub-elements separated by : — category : status : entity.

Status category codes (most common)

Code	Meaning
A0	Acknowledgment / Forwarded
A1	Acknowledgment / Receipt
A2	Acknowledgment / Acceptance into adjudication
A3	Acknowledgment / Returned as un-processable
A4	Acknowledgment / Not Found
A6	Acknowledgment / Rejected for missing information
A7	Acknowledgment / Rejected for invalid information
A8	Acknowledgment / Rejected for relational field in error

Status codes (the second sub-element of STC01)

These are 3-digit codes from the Health Care Claim Status Code List (approximately 800 codes). Common ones:

Code	Meaning
19	Entity acknowledges receipt of claim
20	Accepted for processing
21	Missing or invalid information
35	Claim/encounter not found
116	Claim submitted to incorrect payer
400	Claim is out of balance
403	Entity not eligible for benefits for submitted DOS
560	Entity's additional/secondary identifier

The status text is usually included in STC03 for human-readable lookup.

Entity codes (third sub-element)

Code	Meaning
1P	Provider
IL	Insured (subscriber)
QC	Patient
PR	Payer
82	Rendering provider
85	Billing provider

STC02 — status effective date

STC03 — narrative

Human-readable text. Always read this before deciding what to do.

STC04 — total claim charge

STC05 — claim payment amount (rare in 277CA)

277 (claim status response)

Same STC shape as 277CA, but the codes describe the adjudication state rather than the acknowledgment state. Common categories:

STC01 category	Meaning
F0	Finalized
F1	Finalized / Payment
F2	Finalized / Denial
F3	Finalized / Adjudication complete — no payment
F3F	Finalized / Forwarded
P0	Pending
P1	Pending / In Process
P3	Pending / Pre-pay review
R0	Requests for additional information

See also

• 9.2 — Segment cheat-sheet — the segments these codes live inside.
• 3.4 — Acknowledgments — the workflow for consuming all of these on the claims side.