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Key takeaways
- 99173 is a quantitative visual acuity screening of both eyes using a chart, such as Snellen, HOTV or LEA symbols.
- 99174 and 99177 are instrument-based screenings, read off-site (99174) or on-site (99177).
- Screening codes are billed with a preventive visit, often with modifier EP for Medicaid EPSDT, and not with eye exam codes 92002 to 92014.
- A child referred after a failed screening is seen with an eye exam coded Z01.020 or Z01.021, not with 99173.
What Is CPT Code 99173?
CPT 99173 is the code for a quantitative visual acuity screening of both eyes, done with an eye chart that records a measured acuity for each eye. Pediatric and primary care offices bill it most, at well-child and school-age visits.
The test is a screening, not an eye exam. It checks whether a child needs a referral, and the eye exam that follows is billed with the codes in the ophthalmology CPT codes list.
How Do 99173, 99174 and 99177 Differ?
99173 is a chart-based acuity test, while 99174 and 99177 are instrument-based screenings that differ only in where the results are analyzed. The table compares the vision screening codes.
| Code | What it reports | Usual age |
|---|---|---|
| 99173 | Quantitative visual acuity screening of both eyes with a chart | About 3 years and older, once the child can read a chart |
| 99174 | Instrument-based screening of both eyes, analyzed remotely | Younger children who cannot read a chart |
| 99177 | Instrument-based screening of both eyes, analyzed on-site | Younger children who cannot read a chart |
| 99172 | Automated visual function screening of acuity, alignment, color and fields | Rarely used |
The American Academy of Pediatrics recommends instrument-based screening for young children and chart-based acuity screening once a child can cooperate. Each state's EPSDT schedule sets the exact ages for Medicaid.
When Is 99173 Billed?
99173 is billed with a preventive visit when a chart-based acuity screening is performed and the measured result for each eye is recorded. It is not billed for a quick check that records no numbers.
These are the settings where 99173 is billed most.
- Well-child visits, with preventive E/M codes 99382 to 99385 or 99392 to 99395
- Medicaid EPSDT visits, often with modifier EP on the screening line
- School and sports physicals that include a chart test
The record should name the chart used and the acuity for each eye, such as 20/30 right and 20/40 left.
Can Eye Care Practices Bill 99173?
Eye care practices rarely bill 99173, because visual acuity is already part of the eye exam codes 92002 to 92014 and the eye-focused E/M visit. Billing 99173 with an exam double counts the same test.
An eye practice usually sees the child after a failed screening. That visit is billed as a full eye exam, such as 92004 for a new patient, with a diagnosis that shows why the child came in.
| Diagnosis code | Meaning |
|---|---|
| Z01.020 | Eye and vision exam after a failed vision screening, without abnormal findings |
| Z01.021 | Eye and vision exam after a failed vision screening, with abnormal findings |
When the exam finds a condition, such as amblyopia or a refractive error, code that condition as well. Our pediatric ophthalmology billing team handles these referral visits.
How Do Payers Cover Vision Screening?
Medicaid covers vision screening for children through EPSDT, most commercial plans cover it as preventive care and Medicare does not cover it. Coverage rules differ by age and by plan.
- Medicaid EPSDT. Covered at the ages on the state schedule, often with modifier EP.
- Commercial plans. Covered as a preventive service at recommended ages.
- Medicare. Not covered, because screening is excluded.
- Vision plans. Cover the routine eye exam, not a screening.
When a child cannot finish the screening, many Medicaid plans ask for modifier 52 and expect the screening at the next well visit.
Why Do 99173 Claims Deny?
99173 claims deny most often because they are billed with an eye exam, billed for a patient outside the covered age or billed without a recorded result. These checks catch most of them.
- 99173 billed with 92002 to 92014 or an eye-focused E/M visit
- 99173 billed with 99174 or 99177 to a payer that pays only one
- A screening sent to Medicare
- No measured acuity for each eye in the record
Our ophthalmology medical coding services check screening and exam codes so each visit is billed once.