CPT Code 99392: Well-Child Visit Billing Guide for Ages 1 to 4

What Is CPT Code 99392?

CPT code 99392 is a preventive medicine service code that reports the periodic comprehensive well-child visit for an established patient age 1 through 4 years. It covers a complete age-appropriate history, comprehensive physical exam, developmental surveillance, and anticipatory guidance per the AAP Bright Futures schedule. The code is valid for children age 1 year 0 months through 4 years 11 months on the date of service.

Age and frequency limits: The age window is 1 through 4 years. Most commercial payers allow one preventive visit per calendar year or per 12-month period, while Medicaid EPSDT follows the Bright Futures periodicity schedule, which calls for visits at 12, 15, 18, 24, and 30 months plus annual visits at ages 3 and 4.

Modifier 25 placement: When a same-day sick visit is performed alongside the well-child checkup, Modifier 25 goes on the problem-oriented E/M code (such as 99213), never on 99392 itself.

ICD-10 pairing: Use Z00.129 when no abnormal findings are documented, or Z00.121 when an abnormality is found. Attaching a condition-specific code as the primary diagnosis triggers medical-necessity denials.

99392 Description and Age Range

CPT 99392 reports the periodic comprehensive preventive medicine reevaluation and management of an established patient age 1 through 4 years. It is the code for the routine well-child visit, the most common encounter type in a pediatric practice for this age group. The visit includes a comprehensive age- and gender-appropriate history, a comprehensive examination, and counseling and anticipatory guidance.

Two facts determine whether 99392 is the correct code: the child’s age at the date of service and whether the child qualifies as an established patient. The age window runs from 1 year 0 months through 4 years 11 months. A child who has turned 5 before the visit date moves to 99393. An infant under 12 months falls under 99391. The boundary is read at the date of service, not the date the claim is filed, which matters when a visit falls close to a birthday.

The established-patient designation follows the standard three-year rule. A patient is established if any provider of the same specialty within the same group practice has seen them within the past three years. If no provider in the group has seen the child in that window, the visit is a new-patient encounter and the correct code is 99382, not 99392.

What Is the Frequency Limit for 99392?

Most commercial payers allow one preventive visit per calendar year or per rolling 12-month period for each patient. Some payers enforce a strict 365-day rule from the last preventive visit date, meaning a claim filed 11 months after the prior visit will be denied even though both visits fall in different calendar years. Other payers use a calendar-year window, allowing two visits in the same 12-month span as long as they fall in different benefit years.

Medicaid EPSDT (Early and Periodic Screening, Diagnostic, and Treatment) follows the AAP Bright Futures periodicity schedule, which mandates more frequent visits during the toddler years than commercial payers typically allow. The schedule calls for visits at 12 months, 15 months, 18 months, 24 months, and 30 months, plus annual visits at ages 3 and 4. Each of those visits within the 1-to-4 age window would be coded as 99392 for an established patient.

Payer Type	Frequency Rule	Key Detail
Commercial (most)	Once per calendar year	Some enforce a 365-day rolling window instead
Medicaid EPSDT	Per Bright Futures periodicity	7 visits within the 1-to-4 age window
CHIP	Follows state Medicaid rules	Varies by state; verify before billing
Tricare	Once per calendar year	Aligns with AAP schedule for covered ages

One question we hear constantly from practice managers is why a preventive visit claim was denied when the child clearly needed the visit. In most cases, the denial traces back to a frequency limit the practice did not check before scheduling. The fix is verifying eligibility and the last preventive visit date before the appointment, not after the claim comes back rejected. Practices that use their EMR to flag frequency windows automatically catch these before the child is even in the room.

99392 vs 99382: New vs Established

This is the most common selection error on toddler preventive claims. CPT 99392 is for established patients. Its new-patient counterpart is 99382, which covers the identical age range and nearly identical service content. The only difference is patient status, but the reimbursement rates differ and coding the wrong one triggers audit flags.

The error surfaces most often with transfers, families returning after a gap longer than three years, and practices that have recently changed tax ID or specialty mix. In each scenario, the child may technically be a new patient even though the chart looks familiar. Build the new-versus-established check into your intake workflow rather than leaving it to the coder at the back end. Practices still standardizing their front-office process can start with our walkthrough of billing basics for new practices.

Which ICD-10 Codes Pair With 99392?

Preventive visit claims require a diagnosis code that reflects the preventive nature of the encounter. Using a condition-specific ICD-10 code as the primary diagnosis is one of the fastest paths to a medical-necessity mismatch denial on a well-child visit claim.

The correct primary codes come from the Z00 routine examination family. Z00.129 (encounter for routine child health examination without abnormal findings) is the right choice when the visit reveals nothing abnormal. Z00.121 (encounter for routine child health examination with abnormal findings) is correct when the provider identifies an abnormality, and you then add the specific finding as a secondary diagnosis.

Choosing between the two is a documentation decision, not a shortcut, and getting it right keeps the claim clean. For an example of how a single ICD-10 choice changes the trajectory of a claim, see our coding guide on ICD-10 code I49.9.

Modifier 25 and Same-Day Sick Visits

When a significant, separately identifiable problem is addressed during the same visit as the well-child checkup, Modifier 25 goes on the problem-oriented office visit code (such as 99213 or 99214), not on 99392. The well-child code stays clean. The modifier tells the payer that the sick portion was a distinct service worthy of separate reimbursement.

Place the modifier on the wrong code, or leave it off entirely, and the payer bundles the problem visit into the preventive service and denies the additional line. This same-day well-and-sick scenario is the single most common denial source for toddler preventive claims across the billing companies in our network, and it is also one of the most appealable when the documentation cleanly separates the preventive screening from the focused problem evaluation.

The documentation must show two distinct services: the comprehensive preventive screening on one side and the focused evaluation of the specific problem, an ear infection, a rash, or a behavioral concern, on the other. A note that blends the two into one narrative gives the payer grounds to deny the split.

Billing 99392 With Vaccines and Screenings

Toddler well visits rarely happen in isolation. Several services commonly appear alongside 99392, each with its own billing rules.

Vaccine administration codes (90460 for counseling-based administration or 90471 for non-counseling) plus the vaccine product codes are reported separately and do not require Modifier 25. They are not evaluation and management services, so the same-day modifier logic does not apply.

Developmental screening (96110) and vision screening (99173 or 99174) are frequently performed at these visits. Whether a payer requires a modifier on the screening line, and which modifier, varies by plan. Some payers accept the screening code without a modifier, some require Modifier 59 on the screening, and some want Modifier 25 on the relevant E/M line. Verify the specific payer’s policy and run code pairs through an NCCI bundling edit check before submission.

Practices that run screening tests and labs in-house can capture additional revenue from these visits, but only if the billing workflow handles the code pairing correctly. Our guide on how in-office labs support your medical billing process covers the documentation and billing chain for in-house diagnostics.

Common 99392 Denials and How to Prevent Them

Across the pediatric claims our network partners handle, 99392 denials cluster into a short, predictable list. None of these are coding mysteries. They are workflow gaps, and they are fixable before the claim ever goes out.

Modifier 25 missing or misplaced. The same-day sick visit is denied because the modifier was left off or placed on 99392 instead of the problem-oriented code. Fix: build a claim scrub rule that flags any same-day preventive and E/M pair without Modifier 25 on the E/M line.

Medical-necessity mismatch. A condition-specific primary diagnosis instead of Z00.129 or Z00.121. Fix: lock your preventive visit template so Z00.12x populates automatically as the primary code.

New-versus-established error. The claim should have been 99382. Fix: verify patient status at intake using the three-year rule, not chart familiarity.

Frequency limit exceeded. The payer’s once-per-year or 365-day rule was not checked before the visit. Fix: verify the last preventive visit date during eligibility verification, before the appointment.

Age boundary slip. The child crossed a birthday before the date of service and moved to a different age bracket. Fix: confirm the child’s age at the date of service, not at scheduling.

These denials are the friction that pushes growing practices to stop handling preventive billing in-house. If your denial rate on well-child claims is climbing, our guide on how to find the right pediatric medical billing service walks through what to look for in a billing partner.

Frequently Asked Questions