837I outbound — institutional context

Outcome

An institutional claim is composed as a syntactically valid 837I — with DRG, occurrence codes, value codes, condition codes, and the right revenue-code service lines — and the per-diem grouping aligns with the program's billing period.

Prerequisites

Scope	What it lets you do
edi.transaction.read	View transactions
billing.claim.write	Originate institutional builds

A program configured with filingType = INSTITUTIONAL (rcm-app configuration). A trading partner with 837I outbound capability.

What 837I differs from 837P on

The envelope and most loops are identical. The differences live in:

Loop / segment	837P	837I
Implementation convention	005010X222A1	005010X223A2
BHT06 purpose	CH Chargeable	CH Chargeable
CLM05 POS qualifier	Always B:1	Always A:1
Bill type	(not used)	CL103 3-character bill type
CL1	(skipped)	Required — admit type / source / discharge status
HI*DR	(rare)	DRG code + quantity + version
HI*BH	(rare)	Occurrence codes (74 LOA, 11 onset, etc.)
HI*BE	(rare)	Value codes (80 covered days, 81 non-covered, others for cost share)
HI*BG	(rare)	Condition codes
Service line	SV1 (proc + modifiers)	SV2 (revenue code + proc + amount)
Rendering provider	2310B / per line 2420A NM1*82 + PRV*PE	2310D / per line 2420C NM1*82, no PRV — claim level when every line names the same clinician; never a repeat of the 2310A attending provider
Service facility	2310C NM1*77	2310E NM1*77 — same rule: only when it differs from the 2010AA address
Referring provider	2310A / per line 2420F NM1*DN	2310F / per line 2420D NM1*DN — claim level when every line names the same one
Pay-to address	2010AB NM1*87*2 + N3/N4	Same 2010AB, same rule: only when it differs from the 2010AA address

Source: packages/x12/src/outbound/claim-837i.ts.

The 837I names its provider in 2310A (attending, NM1*71). The rendering clinician follows the 837P's rule, with the attending in place of the billing provider as the one that already covers a line:

• Every line names the same clinician → claim level. A 2310D is sent only when that clinician is not the 2310A attending; otherwise nothing.
• The lines name different clinicians → no 2310D. Each line whose clinician is not the attending carries its own 2420C (NM1*82, no PRV), after 2410 and before 2420D. A line whose clinician is the attending, or has no NPI on its date of service, carries none.

2310D and 2420C are never sent together, and the writer drops a line's 2420C that repeats the claim-level clinician (2310D when sent, else 2310A). No REF secondary IDs are sent in 2420C; a payer that needs one adds it with a companion-guide rule scoped to 2420C. The operating physician loops (2310B / 2310C, 2420A / 2420B) are not sent — there is no source data for them. The service facility, referring provider and pay-to rules are the 837P's, described in 3.1 — 837P outbound.

CL1 — institutional context header

Required at the 2300 loop level for institutional claims:

CL1*1*1*30~

Element	Meaning
CL101	Admission type code. 1 Emergency, 2 Urgent, 3 Elective, 4 Newborn, 5 Trauma, 9 Information not available.
CL102	Admission source code. 1 Physician referral, 2 Clinic referral, 4 Transfer from hospital, 7 ER, 8 Court / law enforcement, etc.
CL103	Patient discharge status. 01 Routine, 02 Discharged to short-term hospital, 03 Discharged to SNF, 06 Discharged home with home health, 20 Expired, 30 Still patient (used on interim bills), 40 Hospice — home, 41 Hospice — facility, 50 Discharged to home for hospice.

HI segments — the institutional codes

Each HI segment carries up to 12 composite code positions; multiple HI segments cluster by qualifier:

HI*BK:F329~                     (principal diagnosis)
HI*BF:F100:F329:Z794~           (other diagnoses)
HI*DR:470*A0~                   (DRG version A0 = 470)
HI*BH:11:D8:20251015            (occurrence — onset 2025-10-15)
*BH:74:D8:20251020              (occurrence — LOA 2025-10-20)
:RD8:20251020-20251022~         (range)
HI*BE:80:::5~                   (value — 80 covered days = 5)
*BE:81:::2~                     (value — 81 non-covered days = 2)
HI*BG:67~                       (condition — beneficiary admitted within 3 days of LOA discharge)

Qualifier	Meaning
BK	Principal diagnosis (one per claim)
BF	Other diagnoses (up to 8)
BJ	Admitting diagnosis
BBR	Principal procedure ICD-10-PCS
BBQ	Other procedure
BR	Patient reason for visit (outpatient)
DR	Diagnosis-Related Group (DRG)
BH	Occurrence code
BI	Occurrence span
BE	Value code
BG	Condition code
TC	Treatment code

Common occurrence codes (HI*BH)

Code	Meaning
01	Auto accident
04	Accident — employment-related
05	Other accident
11	Onset of symptoms
12	Date of onset for chronically dependent illness
17	Date outpatient occupational therapy plan established / reviewed
24	Date insurance denied
25	Date benefits terminated
27	Hospice certification date
74	Non-covered level of care / leave of absence

Common value codes (HI*BE)

Code	Meaning
01	Most common semi-private rate
06	Medicare blood deductible
08	Medicare lifetime reserve days
09	Medicare coinsurance days
38	Lifetime reserve days
39	Coinsurance days
41	Black lung
80	Covered days
81	Non-covered days

Common condition codes (HI*BG)

Code	Meaning
02	Condition is employment related
04	Information only bill
05	Lien has been filed
06	ESRD patient in first 30 months of entitlement covered by employer group
40	Same-day transfer
45	Ambulance carrying patient who refused medical care
60	Day outlier
61	Cost outlier

SV2 — institutional service line

SV2*0301*HC:99213*100.00*UN*1~

Element	Meaning
SV2-01	Revenue code (4-digit). 0301 Lab — chemistry, 0250 Pharmacy general, 0450 ER general, 1004 Inpatient psych.
SV2-02	Composite procedure code (same shape as 837P SV1-01).
SV2-03	Charge amount.
SV2-04	Unit basis (typically UN).
SV2-05	Units.
SV2-06	(Non-covered charge.)
SV2-07	(Tax).

The revenue code is mandatory; the procedure code is optional for some revenue codes (e.g. inpatient room-and-board often does not require HCPCS).

Per-diem grouping

The platform groups per-diem charges per the program's institutionalBillingPeriod:

Period	What goes on the claim
DAILY	One claim per day.
WEEKLY	All days in a 7-day window.
MONTHLY	All days in a calendar month.
SPAN	Admission through discharge as a single claim.

The grouper applies before claim build. Each grouped claim carries one SV2 per covered day (or one per revenue code per covered day, when multiple revenue codes apply).

Steps

The flow is identical to 837P (3.1) — same consumer, same routing, same companion guide application — with the generator selected based on the program's filing type. Operators rarely choose between 837P and 837I directly.

Validation

Check	Expected
Outbound tx_type = 837I record appears	Yes.
CL1 segment present in 2300 with admit type / source / discharge status	Yes.
HI*DR present when DRG is set on the source claim	Yes.
SV2 per service line, with revenue code in SV2-01	Yes.
Sum of HI*BE*80 covered days + HI*BE*81 non-covered days equals stay LOS	Yes.

Troubleshooting

Symptom	Cause	Fix
Built as 837P instead of 837I	Source program's filingType is PROFESSIONAL	Edit the program in the rcm-app; rebuild the claim.
HI*BE*80 + BE*81 does not equal LOS	LOA not recorded on the stay	Capture the LOA on the source stay record before building.
Generator produces error "DRG not in master"	DRG code typo or master out of date	Confirm the DRG; if the master is stale, refresh it (rcm-core admin).
Partner rejects with "occurrence 74 missing date"	LOA recorded with one date, not a range	Edit LOA to specify both start and end.

Next

3.3 — Submission routing rules