HCPCS M1226: IOP Measurement Not Documented, Reason Unspecified

HCPCS Level II code M1226 denotes that an intraocular pressure (IOP) measurement was not documented and no specific reason was recorded. This administrative code is used in ophthalmology and optometry service lines to capture instances where a standard diagnostic element—IOP—is missing from the clinical record. Nationally, accurate documentation of IOP is important for glaucoma screening and management, quality measurement, and claims integrity; a standardized code for undocumented IOP supports consistent reporting and auditing.

Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare and Medicare. Readers will find context on the clinical scenario reflected by the code, the typical outpatient ophthalmology or optometry setting where it appears, and the role such a code plays in administrative reporting. The publication summarizes expected use cases, documentation implications, and where readers can look for related billing or quality measure guidance.

This report does not provide state-level detail. It offers national perspective on documentation coding practice, the potential impacts on quality measurement and claims processing, and identifies where additional documentation or coding specificity may be required. Data not available in the input.

Billing Code Overview

HCPCS Level II code M1226 indicates Iop measurement not documented, reason not otherwise specified. The code represents a documentation entry noting that intraocular pressure (IOP) measurement was not recorded for the patient and that no specific reason is provided in the record.

Service type: Ophthalmology/Optometry diagnostic encounter without documented IOP measurement

Typical site of service: Outpatient ophthalmology or optometry clinic visit

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Clinical Context

A 68-year-old patient with a history of primary open-angle glaucoma presents to an ophthalmology clinic for routine follow-up. The clinician documents intraocular pressure (IOP) measurement as a standard component of the visit; however, on this encounter the recorded chart lacks a documented IOP value and no reason for omission is entered. Typical workflow for IOP measurement involves triage staff or ophthalmic technicians performing tonometry (applanation or non-contact) prior to provider evaluation, with results recorded in the chart. When IOP is omitted, billing staff may append the HCPCS Level II code M1226 to indicate that an IOP measurement was not documented and no specific reason is provided. Typical site of service is an outpatient ophthalmology clinic or ambulatory surgical center during routine eye examinations or glaucoma monitoring visits. Common patient scenarios include inability to obtain measurement due to equipment failure, uncooperative patient who nevertheless receives the visit, or an oversight where the measurement was not recorded; in all cases the encounter proceeds without a documented IOP value and no explanatory note is present in the record.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when work required is substantially greater than typically required, and documentation supports increased work for the visit where IOP measurement was omitted but additional unlisted services were performed.

Taxonomy Code	Specialty	Notes
`207K00000X`	Ophthalmology	Primary specialty performing IOP measurement and managing glaucoma patients.
`207KA0000X`	Optometry	Commonly performs IOP screening and documentation in ambulatory settings.
`2086S0121X`	Ophthalmic Plastic & Reconstructive Surgery	May be involved when periocular surgery impacts IOP measurement or documentation.
`261QP2300X`	Physician Assistant	Often documents and performs tonometry under supervision in clinic.
`363L00000X`	Registered Nurse	Nursing staff or ophthalmic technicians support IOP measurement workflow and documentation.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`H40.11X0`	Primary open-angle glaucoma, mild stage	Common indication for routine IOP monitoring; absence of a documented IOP is relevant to ongoing management.
`H40.1110`	Primary open-angle glaucoma, mild stage, right eye	Laterality-specific code often used for glaucoma surveillance where IOP is critical.
`H40.1210`	Primary open-angle glaucoma, moderate stage, right eye	Progressive glaucoma stages require IOP monitoring; missing measurements may affect staging and treatment decisions.
`H40.9`	Glaucoma, unspecified	General glaucoma diagnosis prompting routine tonometry; omission of IOP documentation impacts disease control assessment.
`H52.13`	Myopia, bilateral	Refractive errors are common in ophthalmology visits where IOP is often checked; missing IOP may be incidental but should be documented.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`92002`	Ophthalmological services: medical examination and evaluation, new patient; intermediate, with initiation of diagnostic and treatment program	Performed for new patient eye evaluations where IOP measurement is typically obtained; omission may be noted with `M1226`.
`92004`	Ophthalmological services: comprehensive, new patient, with initiation of diagnostic and treatment program	Comprehensive new patient exams include tonometry; `M1226` indicates IOP missing from such comprehensive exams.
`92012`	Ophthalmological services: medical examination and evaluation, established patient; intermediate, with initiation or continuation of diagnostic and treatment program	Used for established patients; IOP measurement omission during these visits is reported with `M1226`.
`92014`	Ophthalmological services: comprehensive, established patient, with initiation or continuation of diagnostic and treatment program	Comprehensive follow-up exams where IOP measurement is expected; `M1226` documents missing IOP.
`92100`	Serial tonometry (for glaucoma), with interpretation and report	Directly describes IOP measurement procedures; when tonometry is not documented, `M1226` is used instead of this CPT code being billed for that component.

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Summary & Overview