How Do You Bill an Observation Stay?

What Has to Be in Place Before You Bill Observation?

• A physician, or another person the state and the hospital's bylaws allow to admit patients or order outpatient tests, has ordered observation. Claims Processing Manual chapter 4, section 290.1 covers observation only on that order.
• The chart shows the clock time observation started, in line with the physician's order.
• Timed, signed physician notes show the patient was in a physician's care during observation and that the physician assessed the risk that led to it. The comprehensive payment test, covered below, asks for both.
• A MOON was delivered if the patient is on Medicare and observation passed 24 hours.

Medicare does not permit retroactive orders or the inference of an order. Chapter 1, section 50.3.2 repeats that for hours that came before the order, so a late order does not buy back the earlier hours.

How Do You Build the Observation Claim Line by Line?

Use one outpatient claim for the whole encounter. The Outpatient Code Editor evaluates claims one at a time, so chapter 4 says the other non-repetitive services given on the same day as observation must be reported on the same claim.

1. Open the claim as an outpatient bill, type 13x for hospitals paid under OPPS. Chapter 25 requires FL 17, the patient discharge status, on hospital outpatient claims.
2. Report the front-end visit first: the emergency department visit, clinic visit or critical care service, each with its revenue code in FL 42, HCPCS code in FL 44 and line item date in FL 45.
3. Add the observation line: revenue code 0762 (or the general 0760) in FL 42, HCPCS G0378 in FL 44 and the hours in FL 46.
4. Use the date observation began as the line date in FL 45. If observation crosses a calendar day, the manual puts all hours on a single line with that start date.
5. Add the lab, imaging and drug lines furnished during observation under their own revenue and HCPCS codes.
6. Report every charge, including packaged ones. Chapter 4, section 10.4 says charges for packaged services feed outlier payments and future rate setting.

The observation reference page lists the form locators and the hours rules in short form. Where the physician bills the visit, initial hospital care codes such as 99221 are used for both observation and inpatient care since CY 2023.

How Do You Count Observation Hours?

Start at the documented clock time of the order's start and stop when all medically necessary observation services end. Round to the nearest hour and put the result in the units field of G0378.

• Time continues after the discharge order while follow-up care is still being given, and ends when care is finished or the patient is admitted or discharged.
• Time spent waiting for a ride home is not observation.
• Standing observation orders after outpatient surgery are not recognized, and a normal recovery period of about 4 to 6 hours is billed as recovery room care.
• Observation is not billed at the same time as a procedure that includes active monitoring, such as a colonoscopy or chemotherapy.
• When such a procedure interrupts observation, the manual lets the hospital either add the separate observation periods or subtract the procedure's average length from the total.

When Does Observation Get Paid More Than a Packaged Amount?

G0378 is status indicator N, so it has no payment of its own. Chapter 4, section 290.5.3 says comprehensive payment through APC 8011 is possible only when all of the following are met.

If any test fails, the usual APC logic applies and the observation payment is packaged into the other separately paid services on the claim. Hospitals must not bill the patient for reasonable and necessary observation that OPPS packages. Packaged is not the same as non-covered. See OPPS and APCs for how the comprehensive payment is set.

What Happens When the Patient Is Admitted, or the Order Is Withdrawn?

• If the patient is admitted, observation time ends at admission. The hospital's own outpatient services in the 3 days before admission then move to the inpatient claim under the payment window, as explained in what gets bundled. Revenue code 0762 is not on the manual's list of diagnostic revenue codes, so observation is treated as nondiagnostic.
• If the inpatient order is withdrawn through utilization review before billing, condition code 44 moves the whole episode to the outpatient claim. Hours before the observation order go on an uncoded line with revenue code 0762, and G0378 starts only after the order.
• If a Part A claim is denied after discharge, the hospital cannot turn the stay into observation. Benefit Policy Manual chapter 6, section 10.1 excludes observation from the Part B services payable after a denial.

The inpatient decision itself is in our post on the two-midnight rule.

How Do You Fix an Observation Claim That Came Back Wrong?

1. Pull the order time, the nurse's start note and the end of observation services, and recompute the hours.
2. Check that G0378 sits on the same claim as the ED or clinic visit, and that nothing is on a separate claim for the same day.
3. Send an adjustment with one claim change reason code. Chapter 1, section 130.1 says the frequency digit is 7 for a debit-only change.
4. If the line was denied, request a redetermination within 120 calendar days of receipt under 42 CFR 405.942.

How Does Nucleus Align Handle Observation Billing?

Our hospital and facility billing team validates revenue codes, patient status, condition codes and payer-specific rules on each institutional claim and works denials for inpatient, outpatient and emergency care. Learn more about hospital and facility billing, or book a call.