CPT code 99423 – Online digital evaluation and management service

Key takeaways

CPT code 99423 bills 21 or more minutes of online digital E/M work over 7 days, started by an established patient’s portal message.

The total counts every minute the billing clinician spends reviewing records, researching and replying, across every session in the 7-day period.

Don’t bill 99423 when a related E/M visit happened in the 7 days before the message, or takes place during the 7-day period.

Pabau, the practice management platform we build, sends US claims through Claim.MD with eligibility checks, while your notes carry the time log and conflict check.

CPT code 99423 covers 21-plus minutes of portal work in 7 days

CPT code 99423 is the online digital evaluation and management (E/M) code for established-patient inquiries totaling 21 or more minutes over 7 days.

The American Medical Association (AMA) publishes it as the top tier of the 99421-99423 family. All three codes share one framework. The patient starts the contact, the exchange is asynchronous and non-face-to-face, and only established patients qualify.

Asynchronous means the clinician doesn’t answer in real time. The patient sends a message through a HIPAA-compliant patient portal, and the clinician reviews it and replies on their own schedule.

The 7 days begin when the clinician first personally reviews the message. Time spent on prior records, research and writing the response all counts toward the total.

The 7-day time total decides the tier

The 99421-99423 family uses cumulative time as its only tier rule. Add every minute the billing clinician spends on the inquiry, across as many sessions as it takes, then pick the code that total reaches.

Shorter inquiries go to 99421 or 99422, and the ladder below shows where each band starts and what it pays.

Under 5 minutes doesn’t meet any code in the family, so don’t bill it. Count whole minutes and never round up to reach the next tier. Record start and stop times, or each session’s total, so an auditor can rebuild the number you billed.

Watch for one timing trap. If you billed a lower tier before the 7 days closed and the work kept going, payers expect one code for the whole period. That usually means a corrected claim replacing the 99421 or 99422 with the higher tier.

Only the billing clinician’s time, for an established patient, counts

CPT code 99423 is billed by a physician or other qualified health care professional (QHP) who can report E/M services independently. The claim goes under the performing clinician’s own NPI, and incident-to billing doesn’t apply.

• Physicians (MD, DO) in any specialty who provide E/M services
• Nurse practitioners (NPs) billing under their own NPI, within state scope-of-practice rules
• Physician assistants (PAs) billing under their own NPI, within state regulations
• Clinical psychologists, clinical social workers and therapists can’t report E/M services, so they use the nonphysician codes 98970-98972 instead
• Nurses and medical assistants can help with the inquiry, but their time doesn’t count toward the total

The established-patient rule has no exceptions. A first-time contact through the portal can’t be billed under 99421-99423, however long it takes. Billing for a new patient is a compliance risk and a common denial reason.

How a 99423 claim moves from portal message to payment

Here’s one inquiry followed through the medical billing process, using an illustrative patient. On Monday, an established patient with type 2 diabetes messages the portal about rising morning glucose readings and a new medication’s side effect.

The physician spends 9 minutes on the glucose log and chart that afternoon. On Tuesday, checking the medication question takes another 8 minutes. On Wednesday, writing the plan and replying takes 6 more. That’s 23 minutes inside 7 days, so the claim is 99423.

1. Confirm the patient started it. Note the date and time of the patient’s message and of the clinician’s first review. Practice-sent reminders and recall messages don’t qualify.
2. Log each session as it happens. Record the minutes and what was done, whether that’s record review, research or the reply. Send the response through the same HIPAA-compliant portal.
3. Total the time when the 7 days close. Add the sessions together and check that the total reaches 21 minutes.
4. Run the conflict check. Look for a related E/M visit in the 7 days before the message, or one during the period. If either exists, the portal work belongs to that visit.
5. Finish the note, then code. Complete every documentation check below, select 99423 and add any modifier the payer requires.
6. Submit and track the claim. Send it through your clearinghouse after an eligibility check, then watch the remittance for a denial code.

Before you submit: Seven documentation checks

Every element of the code definition has to show in the record. One missing element can turn into a denial, or an overpayment finding on audit. Build these into a standardized note template, so the clinician completes them before replying.

• Patient-initiated contact: The patient sent the inquiry through a HIPAA-compliant platform, with the date and time of the first message
• Cumulative time: Total minutes spent reviewing the inquiry, researching, reviewing records and composing the response, at 21 or more for 99423
• Nature of the inquiry: Summarize the patient’s clinical question or concern
• Clinical response: The advice, management decision or instructions given to the patient
• Medical decision making (MDM): The complexity of the decision, including data reviewed and risk level
• Established patient status: The patient has a prior documented relationship with the practice
• No conflicting E/M visit: No related visit in the 7 days before the message or during the 7-day period

Medicare pays roughly $46 for 99423 in 2026

Medicare sets the 99423 rate each year through the Medicare Physician Fee Schedule (MPFS). The table shows approximate national non-facility and facility rates. Rates change every calendar year.

Check current amounts in the CMS Physician Fee Schedule lookup tool or with your Medicare Administrative Contractor (MAC) before you submit.

The FastRVU lookup tool breaks 99423 into work, practice expense and malpractice RVUs, plus the geographic adjustments that move your local payment. Commercial payers negotiate their own rates, which can land above or below Medicare.

Medicare covers 99423, and the patient shares the cost

Yes, Medicare Part B pays for 99423 as an online digital E/M service under the Medicare Physician Fee Schedule. The usual Part B cost sharing applies, which can surprise patients who assume a portal message is free.

• Cost sharing: The Part B deductible and 20% coinsurance apply
• Billing entity: The performing QHP’s own NPI, with no incident-to billing
• Patient eligibility: Established Medicare beneficiaries only
• Medicaid: Coverage varies by state, so confirm with your state Medicaid agency
• Commercial payers: Most major insurers cover 99421-99423, but check each payer’s current policy or the AAPC code reference for payer-specific guidance

Medicare’s virtual-care policies have changed often in recent years. Confirm the current rules with your MAC rather than relying on guidance from an earlier coverage period.

Six reasons 99423 claims get denied, and how to fix each

Most 99423 denials are preventable, and the same few errors show up from practice to practice. A denial management workflow catches them before submission rather than after. When one slips through, the claim denial codes on the remittance tell you which fix applies.

Focusing on submitting a clean claim the first time cuts out the costliest part of the denial cycle. That’s the time spent working remittances, writing appeals and resubmitting.

Phone calls, video visits and other services 99423 doesn’t cover

Several non-face-to-face services look like 99423 but bill under other codes. Mixing them up is a common unbundling or upcoding risk.

• Telephone-only contacts: The 99441-99443 phone codes were deleted on January 1, 2025. Audio-only visits now report under the telemedicine codes 98008-98015, or 98016 for a brief check-in. Medicare pays for these differently, so check with the payer or your MAC.
• Synchronous video visits: Real-time video visits bill as E/M services under the payer’s telehealth rules, not as online digital E/M.
• Remote physiologic monitoring data (CPT 99091): Interpreting device data, such as blood pressure or glucose readings, bills under 99091. It needs at least 30 minutes of clinician time per 30 days.
• Interprofessional consultations (CPT 99451-99452): When one clinician consults another about a patient by phone or internet, that’s the interprofessional family, not 99423.
• Practice-initiated messages: Communication the practice starts, including post-visit instructions and appointment reminders, doesn’t meet the patient-initiation rule.
• Replies from non-QHP staff: Portal messages answered only by a nurse, medical assistant or other non-QHP staff member don’t qualify for 99423.

How Pabau keeps 99423 claims moving from portal to payer

99423 revenue usually slips away before a claim exists. A clinician answers a portal message between appointments, doesn’t note the minutes, and the encounter never reaches billing.

In Pabau, patients send messages through the patient portal, which the practice switches on. The clinician records each session’s minutes and the 7-day conflict check in the patient’s notes, where an auditor will look for them. When the note is done, the claim pre-fills from the patient record, and streamlined claims management checks the required fields before it can be sent.

US claims go to Claim.MD as 837P files, with an eligibility check before submission. Remittances post back from the ERA, so you can see which 99423 claims paid and which need work.

Turn portal messages into paid 99423 claims

Pabau pre-fills claims from the patient record, checks required fields and sends US claims through Claim.MD after an eligibility check. Your team stops rekeying portal encounters.

Book a demo

Conclusion

CPT code 99423 pays for work your clinicians already do in the portal. In return, it asks for three habits. Confirm the patient started the contact, log every minute, and check for a related visit before you code.

Start with the log. A practice that records minutes as they happen can bill the right tier and defend it on audit. One that rebuilds the time from memory at the end of the week will underbill, overbill, or both.

Book a demo to see how Pabau turns a finished portal note into a clean claim sent through Claim.MD.

Continue your research

Need a broader overview of the medical billing process? What is medical billing explains the full revenue cycle from patient encounter to payment posting.

Troubleshooting denied claims across your whole claims portfolio? Denial codes in medical billing covers CARC and RARC codes, appeal workflows and prevention strategies.

Want to see where the clearinghouse fits in a 99423 submission? Medical claims clearinghouse explains how 837P files are validated and routed to payers.

Consulting a specialist about the patient instead? CPT code 99451 covers the consulting physician’s side of an interprofessional exchange.

Reviewing device data between visits? CPT code 99457 bills remote physiologic monitoring treatment management time.

Frequently asked questions