Hospital Medicine Billing, Credentialing

Two hospitalists from the same group see the same patient on the same day. Only one subsequent visit gets paid.

Hospitalist billing is full of rules like that, and they repeat across every patient on the census every day. A group that consistently bills one level too low on daily visits, misses split/shared rules for its NPs, or loses track of who’s in observation can give up a meaningful share of its revenue without a single denial to show for it.

Key Takeaways

Admissions and Daily Visits

Since 2023, inpatient and observation care share the same CPT code set. The first visit by the admitting hospitalist bills as 99221, 99222, or 99223, and each later day bills as 99231, 99232, or 99233. Each level is chosen by medical decision-making or by total time on the date of service, including time spent reviewing results, documenting, and coordinating care on the unit. Observation discharge uses the same discharge codes as inpatient discharge.

The admitting physician adds modifier AI to the initial visit for Medicare patients, which identifies them as the principal physician of record. Other physicians who see the patient that day bill their own initial or subsequent visit codes without it.

When the admitting hospitalist sees a patient more than once on the day of admission, the visits combine into one initial care code. On later days, multiple visits by the same hospitalist, or by physicians of the same specialty in the same group, combine into one subsequent visit. Physicians of different specialties in the same group can each bill their own visit.

Choosing the Level

Medical decision-making looks at three things. Those are the problems addressed, the data reviewed and analyzed, and the risk of the treatment plan, and two of the three set the level. A patient with a worsening chronic illness, new labs and imaging to interpret, and a decision about IV medication that needs monitoring for toxicity supports high complexity and a level 3 code.

Many hospitalists default to the middle level every day. For patients who meet high complexity, that habit leaves money behind on every encounter. For stable patients awaiting placement, it overstates the work. The fix is in the note. A progress note that says “continue current plan” supports only a low level, while one that names the data reviewed, the options weighed, and the reason for the plan supports what was done.

Time is the other path. When total time on the date exceeds the time required for the highest level, Medicare pays prolonged services with G0316 for each additional 15 minutes. Commercial plans that follow CPT use 99418 instead.

Same-Day Stays, Discharges, and Consults

When a patient is admitted and discharged on the same date, the hospitalist bills 99234, 99235, or 99236 instead of separate admission and discharge codes. Medicare requires the stay to last at least 8 hours. For a shorter stay, only the initial care code is billed. When the patient is discharged on a later date, the discharge bills as 99238 for 30 minutes or less, or 99239 for more than 30 minutes, and the time has to be in the note.

Medicare doesn’t pay inpatient consultation codes. Hospitalists asked to see a patient on another service bill initial hospital care codes for Medicare, while many commercial plans still accept the consult codes 99252 to 99255. The billing system has to know which applies by payer.

Critical Care

Critical care requires a critical illness that acutely impairs one or more vital organ systems, with a high probability of life-threatening deterioration, and the physician’s direct management of it. Being in the ICU isn’t enough. The note has to show why the patient met that definition on that date and record the total critical care time, excluding time spent on separately billable procedures.

99291 covers the first 30 to 74 minutes. Under CPT, 99292 adds each additional 30 minutes starting at 75 minutes, but Medicare doesn’t pay the first 99292 until total time reaches 104 minutes. Medicare also lets practitioners of the same specialty in the same group add their critical care time together for the same patient on the same day. One practitioner bills 99291, and additional time from the group is billed as 99292 once the threshold is met. An E/M visit earlier on the same day, before the patient became critical, can be billed with modifier 25.

Split/Shared Visits with NPs and PAs

Most hospitalist groups use NPs and PAs, and in the hospital, incident-to billing doesn’t apply. When a physician and an NPP in the same group both see a patient on the same day, Medicare pays the visit under whoever performed the substantive portion, which is either more than half of the total time or a substantive part of the medical decision-making. The claim carries the FS modifier.

Visits billed under the physician pay at the full fee schedule, and visits billed under the NPP pay at 85%. Groups that bill every shared visit under the physician without documentation of who did the substantive portion are exposed on audit. Critical care can also be split/shared, with the same FS modifier.

Bedside Procedures

Hospitalists often perform central lines, thoracenteses, paracenteses, lumbar punctures, and arterial lines. Each one is billed separately from the daily visit when it has its own procedure note. The E/M for that day needs modifier 25 when it goes beyond the routine decision to do the procedure. Our guide to using modifier 25 correctly covers the documentation that holds up.

Imaging guidance depends on the procedure. Ultrasound guidance for vascular access (76937) is billed with a central line when the note documents the vessel evaluation and real-time guidance and an image is saved. Thoracentesis (32555) and paracentesis (49083) include imaging guidance in their codes, so guidance isn’t billed separately with them.

Where Hospital Medicine Claims Get Audited

Payers focus on a few patterns. These include high-level daily visits without documentation that supports them, critical care without a time statement or a qualifying condition, admission and subsequent codes on the same date, split/shared visits billed under the physician without support, and inpatient codes for patients who were in observation when status affects the claim. A daily census that shows each patient’s status and attending of record prevents most of these. Our guide to fixing common medical billing errors covers the broader process.

Hospitalist Credentialing

Board certification and privileges

Most hospitalists certify through the American Board of Internal Medicine or the American Board of Family Medicine, and ABIM offers a Focused Practice in Hospital Medicine designation. Payers verify training, board status, licensure, DEA registration, malpractice history, and an NPDB query. Each hospital grants privileges separately, even within the same health system, so a group covering several facilities needs approval at every one.

NPs, PAs, and locum tenens

Each NP and PA needs their own payer enrollment for split/shared and independent billing. Locum tenens physicians covering for an absent group physician can be billed under the absent physician’s NPI for up to 60 continuous days under Medicare’s fee-for-time compensation rules, using the Q6 modifier. Longer coverage, or coverage of an open position, requires the locum’s own enrollment. Groups that start credentialing late often have new hospitalists working shifts they can’t bill, which is why you can’t bill what you can’t credential.

Hospital Medicine Billing FAQs

What Medwave Does for Hospitalist Groups

Hospitalist claims are high volume and low margin, so even a small error rate costs a lot. Medwave levels admission, subsequent, and discharge visits under the current hospital E/M rules, handles split or shared visits between physicians and APPs, and catches same-day visits by the same specialty. Our billing team runs hospital medicine at a 98% clean claim rate.

Each new hospital contract means privileges plus enrollment with the payers that hospital sees. Our credentialing team runs those together, averaging 85 days, and our payer contracting team helps groups price their coverage agreements with the hospitals.

Starting coverage at a new hospital? Send us the go-live date below.