CPT 99221: initial hospital or observation care, low decision making
99221 reports a first hospital or observation visit when the decision making is straightforward or low, or the day's total time reaches the 40 minute level. The same code covers inpatient and observation patients because CMS merged the two code sets in 2023.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: 99221 is the lowest initial hospital code and applies to inpatient and observation patients alike, since the separate observation codes were deleted in 2023. It is billed once per date. G0316 is not available with it, and a same-day ED visit by the same practitioner is not paid separately.
What does CPT 99221 report?
99221 is the lowest of the three initial hospital codes. It reports the first visit of a hospital stay when the decision making is straightforward or low, or when total time on the date reaches the 40 minute level CMS shows in its short label. Since January 1, 2023 the same code serves a patient admitted as an inpatient and a patient placed in observation.
| Item | Value in the file |
|---|---|
| Short label CMS uses | 1st hosp ip/obs sf/low 40 |
| Payment status | A (active code) |
| Work RVU | 1.63 |
| Total RVU, facility | 2.23 |
| Global period | XXX |
What happened to the observation care codes?
They were deleted and folded into the hospital codes. Chapter 12, section 30.6.8, says that starting in 2023 inpatient and observation care are billed with the same codes, 99221 through 99223, 99231 through 99233, 99238 and 99239, with 99234 to 99236 already covering both.
Observation codes 99218 through 99220 and 99224 through 99226 are deleted. Use the merged set instead. Practitioners still furnish and bill observation services; they just pick from the merged set.
History and exam must still be medically appropriate, but they no longer choose the level. Observation also needs its own record: dated and timed orders, nursing notes and physician progress notes, separate from the ED record (section 30.6.8 A).
Does the two-midnight rule change how you bill 99221?
It does not change the code. The two-midnight rule in 42 CFR 412.3(d) governs when an inpatient admission is generally appropriate for Medicare Part A payment: the admitting physician expects the patient to need hospital care crossing two midnights, with the reasons documented. That is a hospital payment test.
On the practitioner's claim, the visible difference is the place of service. The CMS set describes POS 21 as inpatient hospital, 22 as on-campus outpatient hospital and 19 as off-campus outpatient hospital. A patient moved from observation to inpatient is not a new stay for the initial visit (MLN006764), so the practitioner still bills one initial code.
When is a visit initial rather than subsequent?
It is initial when the patient has not received any professional service from you or a same-specialty colleague in your group during the stay (section 30.6.9 E). It is subsequent otherwise.
Medicare no longer recognizes consultation codes. Section 30.6.10 lets a practitioner report a subsequent hospital code, for the first service a specialist gives, when the work and medical necessity are met. Section 30.6.9.1 F says 99221 requires more than consultation codes 99251 and 99252 did.
If the ED practitioner admits the patient, Medicare pays the initial hospital service and not an ED visit from the same practitioner on that date (section 30.6.9.1 A). A visit in the office on one date and an admission the next date are both paid. See CPT 99284.
How does 99221 appear on the claim?
On the CMS-1500, Item 24D carries 99221, Item 24G carries 1 unit, and Item 24B carries the place of service. The principal physician of record adds modifier AI; other physicians who see the patient do not.
The practitioner MUE table effective October 1, 2026 lists 99221 at 1 per date, indicator 3. The prolonged service code G0316 is not available here: the October 2026 HCPCS file lists it with 99223, 99233 and 99236 only. See hospitalist billing.
Does the hospital bill 99221 too?
No. 99221 is a professional service on the physician's CMS-1500, in Item 24D. The hospital bills its own stay on the UB-04, and Chapter 25 says that on inpatient hospital bills FL 44 shows the accommodation rate, not a HCPCS visit code. For a patient in observation the hospital instead reports observation under revenue code 0760 or 0762, with hours as units on the hourly observation code (Chapter 4 section 290.2).
Billers who reconcile the two claims should expect different units and dates: the physician bills the visit once per date, while the hospital counts hours or days.
Why does a 99221 line deny?
| Code | What X12 says | What usually causes it |
|---|---|---|
| CO-97 | Included in the payment for another service already adjudicated | An ED visit from the same practitioner on the admit date |
| OA-18 | Exact duplicate claim or service (OA, except where state workers' compensation requires CO) | A same-group, same-specialty colleague already billed the initial visit |
| CO-50 | Not deemed a medical necessity by the payer | Note shows no reason for inpatient or observation care |
If these denials keep coming back, our denial management team can work them. The higher levels are 99222 and 99223.
Related codes
- Medicare Claims Processing Manual, Chapter 12: Physicians/Nonphysician Practitioners · CMS
- Evaluation and Management Services (MLN006764, May 2026) · CMS
- Physician Fee Schedule relative value files, RVU26D (October 2026) · CMS
- Medicare NCCI Medically Unlikely Edits, practitioner services table, effective 10-01-2026 · CMS
- Medicare Claims Processing Manual, Chapter 26: Completing and Processing Form CMS-1500 Data Set · CMS
- Place of service code set · CMS
- HCPCS quarterly update, October 2026 alpha-numeric file · CMS
- 42 CFR 412.3 Admissions · eCFR
- Claim Adjustment Reason Codes · X12
- Medicare Claims Processing Manual, Chapter 25: Completing and Processing the Form CMS-1450 Data Set · CMS
- Medicare Claims Processing Manual, Chapter 4: Part B Hospital (Including Inpatient Hospital Part B and OPPS) · CMS
We check every rule, code and deadline against the official source. See our editorial policy.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01When does the two-midnight rule change how a hospitalist bills?
It does not change the professional code. The rule in 42 CFR 412.3(d) is a Part A hospital payment test based on the admitting physician's expectation of care crossing two midnights. For the practitioner, it affects whether the patient is inpatient or outpatient, and so the place of service.
02Is 99221 used for both inpatient and observation?
Yes. Since 2023 Chapter 12, section 30.6.8, has inpatient and observation care billed with the same hospital codes. The old observation codes 99218 to 99220 are deleted. Place of service still reflects where the patient was registered, so check it on every claim.
03What counts as an initial visit?
The patient has received no professional service from you or a same-specialty colleague in your group during the stay. After that, section 30.6.9 E treats your visits as subsequent. A different specialty seeing the patient for the first time can bill an initial code.
04Can an ED visit and 99221 be billed together?
Not by the same practitioner on the same date. Section 30.6.9.1 A says Medicare pays the initial hospital or observation service when the practitioner admits from the ED, and not both E/M services. Services that day are folded into the initial visit.
05Why does a duplicate denial appear on a 99221?
A colleague in your group and specialty already billed the initial visit during the stay, so yours counts as subsequent. Bill the subsequent hospital code that fits, not another 99221, and check the group's charge entry for the whole stay, not just the date.
Admission visits getting bundled or denied?
We check initial versus subsequent status and same-day ED overlap before claims go out.