99421–99423: when portal messages become billable visits

What counts as an e-visit

An e-visit is a patient-initiated, non-face-to-face evaluation and management service delivered through a secure online patient portal, billed on the clinician's cumulative time across a rolling seven-day period 1Ref 1U.S. Department of Health and Human Services (2026).Billing for telehealth.HHS billing guidance describing e-visits as patient-initiated, portal-based, cumulative-time services and the code families that bill them, including the nonphysician online digital codes.. It is the billable message: the patient starts the exchange with a clinical question, you review the history, assess, and respond over one or more portal replies, and the code reflects your total time — not a single reply. The patient must be established, and consent to being billed for the service is expected before you start the clock.

E-visits exist to pay for the clinical work you already do between visits — the substantive back-and-forth that used to be unreimbursed. They are not for scheduling, prescription-refill requests handled clerically, or a message that simply confirms an upcoming appointment. The bar is a genuine evaluation that required your professional judgment.

The codes: 99421–99423 and the therapist equivalents

Which code you bill depends on who you are and how much cumulative time you spent. Physicians and other qualified health professionals who can independently bill evaluation and management use the 99421–99423 family, tiered by total time over the seven days. Clinicians who cannot bill E/M independently — many therapists, social workers, and counselors — use the parallel online digital assessment codes (98970–98972) instead, tiered the same way 1Ref 1U.S. Department of Health and Human Services (2026).Billing for telehealth.HHS billing guidance describing e-visits as patient-initiated, portal-based, cumulative-time services and the code families that bill them, including the nonphysician online digital codes.. Medicare recognizes marriage and family therapists and mental health counselors as billing providers and lists the covered code families for them 2Ref 2Centers for Medicare & Medicaid Services (2025).Medicare and Mental Health Coverage.That Medicare recognizes MFTs and mental health counselors as billing providers and lists the eligible behavioral-health provider types and covered code families..

The practical rule: do not bill a physician e-visit code from a license that cannot bill E/M on its own. Matching the code family to your provider type is the difference between a clean claim and a takeback. This is distinct from the interprofessional consult codes 99446–99449, which pay for one clinician consulting another, not for a patient's portal message.

When you can't bill an e-visit

E-visits carry timing rules that quietly disqualify a lot of portal traffic, and billing through them is where audits land. The service must be patient-initiated, and it cannot be billed when the online exchange arises from a related evaluation and management service the patient had in the previous seven days, or when it leads to an E/M service or the next available appointment within a short window afterward. In those cases the message folds into the visit on either side, and the e-visit disappears.

• Patient must start it. A message you send first, unprompted, is not an e-visit.
• No double-dipping around a visit. If the portal thread is part of a recent or imminent visit, it is not separately billable.
• Cumulative, not per-message. You total your time across the seven days into one code, not one code per reply.
• Consent on file. The patient should know these communications can be billed before the clock starts.

E-visits aren't telehealth visits (and why that helps)

It helps to know that e-visits sit in a different bucket than a video appointment. They are communication technology-based services, not services from the Medicare telehealth list — so the originating-site and place-of-service mechanics that govern a video visit do not apply here 3Ref 3Centers for Medicare & Medicaid Services (2026).List of Telehealth Services.That CMS's telehealth list defines what counts as a Medicare telehealth service, distinguishing e-visits as communication technology-based services outside that list.. There is no live audio-video requirement, no telehealth place-of-service code, and no need for the patient to be at a qualifying site; the exchange is asynchronous, through the portal.

That also means an e-visit is not an audio-only phone visit, which is its own billable category with its own rules. When you are deciding how to capture a piece of between-visit work, the channel decides the code: a portal message thread is an e-visit, a scheduled phone call is a telephone service, and a live video appointment is telehealth. The underlying licensure question — the rule under everything — still turns on where the patient is when the service happens.

Coverage varies by payer — check before you bill

The code definitions are national, but whether a given plan actually pays for e-visits is not, so verify coverage before you rely on the revenue. Medicare established these services, and many commercial plans follow, but Medicaid coverage is set state by state and can differ on eligible provider types, time thresholds, and documentation. Read your state Medicaid program's own manual rather than assuming the Medicare rule carries over — California's Department of Health Care Services, for example, publishes its own billing manuals and fee schedules that control for California Medicaid 4Ref 4California Department of Health Care Services (2026).California Department of Health Care Services.That California Medicaid publishes its own billing manuals and fee schedules controlling e-visit coverage in California, used as a named example of state-by-state Medicaid variation..

Because coverage is uneven, confirm the specific plan's policy during eligibility verification, and know each payer's stance before the portal thread starts. A service you cannot bill is still a service you performed — decide in advance whether you will offer it to patients whose plan will not cover it, and how you will handle that conversation.

Documentation that survives an audit

Because e-visits are billed on time and hinge on being patient-initiated, your documentation has to prove both. Keep the portal thread itself, which timestamps who started the exchange and when, and log your cumulative time in a way that ties to the code you selected. The note should show a real evaluation — the clinical question, your assessment, and your management — not just an acknowledgment that a message was received.

Three records make an e-visit defensible on review: the patient's initiating message, a running time entry across the seven-day window, and consent on file that these communications may be billed. If the thread grew out of a recent visit or led directly into the next appointment, note that too, because that is exactly the fact pattern that reclassifies the work and moves it off an e-visit code.