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- Key Takeaways
- CPT code 99284 is the Level 4 emergency department visit, supported by moderate-complexity medical decision making on two of three elements, and selected by MDM only, not time or severity.
- The data element is the one 99284 charts most often fail to document; implying “ECG obtained” rather than stating the data reviewed and interpreted is the leading cause of a downcode to 99283.
- 99284 sits between two boundaries: dropping to 99283 undercuts a genuinely moderate visit, and settling at 99284 when the chart supports high complexity forfeits a 99285.
- Payers now down-level ED claims by algorithm, and the AMA MDM standard is the same across payers, so a note documenting all three MDM elements is both the defense and the appeal.
- Level 4 and 5 ED codes draw audit scrutiny in both directions, upcoding above peer norms and quiet algorithmic down-leveling, so a quarterly prospective self-audit is the best control.
99284 is the Level 4 emergency department visit, and it is quietly one of the most down-leveled codes in medicine. Payers now cut ED claims by algorithm, not by hand: programs like UnitedHealthcare’s Optum EDC Analyzer and Cigna’s E/M policy automatically reduce a share of Level 4 claims to Level 3, and the reduced payment often posts as an ordinary paid claim, so the practice never sees a denial to appeal. Add the defensive down-coding that happens inside the chart, where providers settle at 99284 when the work supported 99285, and this code sits between two expensive boundaries. Getting 99284 right means proving moderate-complexity medical decision making, and knowing which element the chart most often fails to show. This guide covers what 99284 requires, the lines on either side, and the documentation that holds the level.
Current as of 2026. Always verify code status and payment with your specific payer, since policies change.
99284 at a glance
Attribute | Detail |
Code | 99284 |
Descriptor | Emergency department visit, Level 4, moderate-complexity MDM |
Level selection | Medical decision making only; time and history/exam do not score |
MDM requirement | Moderate complexity on 2 of 3 elements (problems, data, risk) |
Place of service | 23 (emergency department), hospital-based |
Patient type | No new-versus-established distinction |
Billed by | Emergency physicians, NPs, and PAs within scope |
Claims generated | Two: professional (MDM-leveled) and hospital facility (leveled separately) |
Code below / above | 99283 (low MDM) / 99285 (high MDM) |
Reimbursement | Mid-level ED E/M; verify via the CMS PFS Look-Up Tool |
What 99284 represents
99284 reports a Level 4 emergency department visit, supported by moderate-complexity medical decision making. Since the 2023 ED E/M revisions, the level is set by MDM alone; history and exam no longer score, and time is not a selection component for ED codes. A note worth making up front, because older guides get it wrong: 99284 is defined by moderate MDM, not by a “severity” label. The pre-2023 descriptors described severity of the presenting problem, but that language was retired, so what matters now is the decision-making documented, not how the complaint is characterized.
It is reported with place of service 23, in hospital-based emergency departments, by any qualified provider who evaluates and manages the patient. There is no new-versus-established distinction in the ED.
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Moderate MDM: the two-of-three test
99284 requires moderate complexity in at least two of the three MDM elements: the number and complexity of problems addressed, the amount and complexity of data reviewed, and the risk of the management decisions.
- Problems at the moderate level: one or more chronic illnesses with exacerbation, two or more stable chronic illnesses, or an acute illness with systemic symptoms.
- Data at the moderate level: reviewing a moderate amount of data, such as multiple test orders or reviews, an independent interpretation of a test, or discussion with an external provider.
- Risk at the moderate level: moderate risk from the workup or treatment, such as prescription drug management or a decision weighed against hospitalization.
Meet two of those three at moderate and the visit is 99284. Fall short, and it drops to 99283.
A note on time: you may see a “60 to 74 minute” figure attached to 99284. That is the time band for the office visit 99214, not for the ED. Emergency department codes have no time pathway; 99284 is set by moderate MDM only, regardless of how long the visit took.
The element the chart most often misses: data
Here is the point that separates a clean 99284 from a down-leveled one. The most common reason these claims are cut to 99283 is insufficient documentation of the data element. Providers reliably document the problems and the risk, but the data reviewed is often implied rather than stated.
“ECG obtained” does not establish moderate data; “ECG independently interpreted, showing no acute ischemic changes” does. The note has to show the data that was ordered, reviewed, and interpreted, and any discussion with another provider or an independent historian, in explicit terms. When only one element clearly reaches moderate, the payer downcodes. The fix is a note that spells out all three elements, with special attention to the data actually reviewed.
The two boundaries: 99283 below, 99285 above
99284 lives between two codes, and both lines are where revenue is won or lost.
- 99283 (below): low-complexity MDM, for a moderate-severity problem with limited data and low risk, an uncomplicated acute illness or injury. Dropping to 99283 out of caution, or because the data element was not documented, gives up earned revenue on a genuinely moderate visit.
- 99285 (above): high-complexity MDM, for a problem posing a threat to life or bodily function, with extensive data or high-risk decisions like hospitalization or emergency surgery. A chest-pain workup that activates the cath lab is a 99285, not a 99284. Settling at 99284 when the chart supports high complexity is the defensive down-code that drains ED revenue.
Our guide to CPT code 99285 covers the level above and the high-MDM standard in detail.
The dual claim: professional and facility
As with every ED visit, a single 99284 encounter generates two separate claims:
- The professional claim, the provider’s E/M service, leveled by MDM as above.
- The facility claim, the hospital’s resource use, leveled independently by the hospital’s own point system based on interventions like IVs, imaging, and nursing time.
The two levels are scored separately and do not have to match. A 99284 professional level does not dictate the facility level, and treating the two as one is a common revenue-integrity error.
Documentation requirements for 99284
A defensible 99284 claim rests on a note that proves moderate MDM on two of three elements:
- The problems addressed and their status (chronic exacerbation, acute illness with systemic symptoms)
- The data ordered, reviewed, and independently interpreted, stated explicitly, and any external discussion
- The risk of the management decisions, such as prescription management or a hospitalization decision considered
- The clinical reasoning, not just the final diagnosis
- A medically appropriate history and exam, which are performed but do not score
Of these, the data element is the one most often under-documented, so state the tests ordered, the independent interpretation, and any external discussion explicitly; a note that only implies the data is the most common reason a 99284 is cut to 99283.
Modifiers and diagnoses
Modifiers:
- Modifier 25: append to the E/M when a significant, separately identifiable E/M is performed the same day as a procedure, common in the ED when an evaluation accompanies a procedure.
- Modifier 27: a facility modifier for multiple same-day outpatient hospital E/M encounters.
Diagnoses:
- 99284 is supported by conditions such as abdominal pain with a workup (R10.9), an asthma exacerbation (J45.901), or dehydration requiring IV fluids (E86.0), paired with documentation of the moderate decision-making, since the diagnosis alone does not set the level.
- The same complaint can land at different levels depending on the decision-making, not the diagnosis: a chest-pain workup (R07.9) that stays moderate supports 99284, while one that reaches high complexity, with hospitalization or extensive data, supports 99285.
99284 coding guidelines by payer
The AMA MDM standard sets the code, but payers apply it through their own E/M policies, and the Level 4 and 5 ED claims are exactly what those policies target:
- Medicare and the MACs. ED levels rest on MDM under the 2023 guidelines, with no time pathway. MACs publish medical-review and documentation expectations, and traditional Medicare does not require prior authorization for emergency services.
- UnitedHealthcare. Uses the Optum EDC Analyzer, an algorithm that assigns a facility ED level based on the presenting problem, diagnostic workup, and complicating conditions, and flags or down-levels claims that do not align.
- Cigna. Maintains an E/M reimbursement policy (revised 2025) that governs review of Level 4 and Level 5 ED claims against CMS coding principles and the CPT descriptors.
- Prudent layperson standard. Across payers, federal law requires emergency coverage to be based on the presenting symptoms a prudent layperson would consider an emergency, not the final diagnosis, so a 99284 workup that ends in a benign diagnosis is still a covered emergency visit.
The practical takeaway: the documentation standard is the same everywhere, two of three MDM elements at moderate complexity, but each payer’s policy is how that standard gets enforced, so verify the specific plan’s E/M policy and keep the note aligned to the MDM elements it will be scored against.
Compliance and audit risk for Level 4 ED E/M
Level 4 and 5 ED codes carry elevated scrutiny, and the risk runs in two directions:
- Upcoding exposure. The OIG actively monitors high-level E/M trends, and a provider or group whose Level 4 and 5 mix runs well above peer norms draws post-payment review. Billing 99284 when the chart supports only low MDM is an overpayment finding waiting to happen.
- Down-leveling exposure. The more common day-to-day risk is the reverse: algorithmic cuts to 99283 that quietly reduce revenue, often posting as paid claims rather than denials.
- The shared defense. Both are managed the same way: contemporaneous notes that document all three MDM elements explicitly, and a prospective internal audit, pulling a sample of Level 4 claims each quarter to confirm two of three elements are documented at moderate complexity before payers do it for you.
The goal is accuracy in both directions: bill the level the documentation supports, no higher and no lower, and keep the record able to prove it.
Common denials and how to avoid them
- Algorithmic down-leveling to 99283. Many payers auto-reduce Level 4 claims; the defense is a note that clearly shows two moderate MDM elements, and these cuts are appealable with the record and the AMA MDM standard.
- Weak data documentation. The most common MDM gap; state the data reviewed and interpreted explicitly.
- Defensive down-coding from 99285. Billing 99284 when the chart supports high complexity forfeits revenue.
- Billing by time. There is no time pathway for ED codes; a long visit does not support 99284.
- Facility-professional mismatch. The two claims are leveled independently.
Reimbursement
99284 is paid under the Medicare Physician Fee Schedule on the professional side, sitting between 99283 and 99285 in value, and the facility claim is reimbursed separately under the hospital outpatient system. The gap between levels is real money across an ED’s volume, which is exactly why both the under-documentation that drops 99284 to 99283 and the defensive coding that drops 99285 to 99284 matter. Treat any single figure as illustrative and confirm current professional rates through the CMS Physician Fee Schedule Look-Up Tool, which updates annually. Our guide to CPT code 99214 covers the parallel moderate-MDM standard in the office setting, and our complete guide to denial management covers appealing algorithmic down-levels.
The bottom line
99284 is a moderate-MDM code squeezed between two boundaries and a down-leveling algorithm. Prove moderate complexity on two of three elements, document the data you reviewed rather than implying it, do not shrink to 99283 when the work was moderate or to 99284 when it was high, and keep the professional and facility claims straight. For practices that would rather not defend ED levels chart by chart, Neolytix has supported healthcare organizations across the United States for over 14 years, with emergency department coding and appeal support built into its medical billing services so Level 4 claims hold up before they go out.
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Neolytix partners with healthcare organizations across revenue cycle, credentialing, and administrative operations ,14+ years of expertise and AI-enabled automation to reduce inefficiencies and drive sustainable growth.
This guide reflects Neolytix’s expertise in healthcare revenue cycle management and is intended for educational purposes only. It does not constitute legal or compliance advice. CPT codes and reimbursement rates are periodically updated by the AMA and CMS.
Sources
- American Medical Association. CPT emergency department E/M codes (99281 to 99285) and the 2023 MDM guidelines. https://www.ama-assn.org/practice-management/cpt
- CGS Medicare. Emergency department visit documentation and medical review guidance. https://www.cgsmedicare.com/partb/mr/pdf/99285.pdf
- Centers for Medicare & Medicaid Services. Physician Fee Schedule Look-Up Tool. https://www.cms.gov/medicare/physician-fee-schedule/search
- AAPC. CPT code 99284 reference. https://www.aapc.com/codes/cpt-codes/99284
Frequently Asked Questions
What is CPT code 99284 used for?
99284 is the Level 4 emergency department visit, reported when the encounter involves moderate-complexity medical decision making. It covers problems like an acute illness with systemic symptoms, a chronic illness with exacerbation, or a workup requiring moderate data and moderate risk. It is billed with place of service 23 and is selected by MDM, not by time.
What is the difference between 99283 and 99284?
Both are emergency department visits, separated by medical decision making. 99283 requires low-complexity MDM; 99284 requires moderate complexity on at least two of the three MDM elements. The most common reason a 99284 is downcoded to 99283 is insufficient documentation of the data reviewed, so the note must state the data explicitly.
What is the difference between 99284 and 99285?
99284 requires moderate-complexity MDM; 99285 requires high complexity on two of three MDM elements, with a problem posing a threat to life or bodily function. A chest-pain workup that leads to hospitalization or activates the cath lab is a 99285. Settling at 99284 when the chart supports 99285 is a common, costly under-code.
Why do 99284 claims get downcoded?
The leading reason is that the documentation does not clearly show moderate complexity on two of three MDM elements, most often the data element. Many payers also run algorithms that automatically down-level Level 4 claims to Level 3, and the reduced payment can post as a paid claim. A note that spells out all three MDM elements is the defense.
Can 99284 be billed based on time?
No. Emergency department E/M codes (99281 to 99285) are selected by medical decision making only. Time is not a descriptive component for ED codes, so a long visit does not support 99284. The level rests entirely on whether the documentation establishes moderate-complexity MDM on two of three elements.
