Q02
BillableMicrocephaly
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is Q02 an HCC code?
Yes. Q02 maps to Spinal Cord Disorders/Injuries under the CMS-HCC V28 risk adjustment model (and Spinal Cord Disorders/Injuries under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for Q02
For Q02to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed Q02 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
Q02 is the ICD-10-CM diagnosis code for microcephaly. A birth defect where the baby's head and brain are smaller than normal, which can affect development and function. Q02 sits in the ICD-10-CM chapter for congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (q00-qa0), within the section covering congenital malformations of the nervous system (q00-q07).
Under the CMS-HCC V28 risk adjustment model, Q02 maps to Spinal Cord Disorders/Injuries (HCC 182) with a community, non-dual, aged base RAF weight of 0.478. Under the older V24 model, Q02 mapped to the same category but with a base RAF weight of 0.481 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Document the severity (mild, moderate, severe) if specified in clinical notes. Because Q02 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q02 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the severity (mild, moderate, severe) if specified in clinical notes
- •Note any associated conditions such as intellectual disability or seizures
Clinical Significance
Microcephaly represents significantly reduced head and brain size at birth, indicating impaired brain development with high risk for intellectual disability, developmental delays, and neurological complications. This diagnosis requires comprehensive evaluation for underlying causes and early intervention services.
Documentation Requirements
- ✓Head circumference measurements below 2-3 standard deviations for gestational age
- ✓Documentation of small brain size on neuroimaging
- ✓Associated dysmorphic features if present
- ✓Maternal history including infections, exposures, genetic factors
- ✓Neurological examination findings
- ✓Genetic testing results if performed
- ✓Developmental assessments and early intervention referrals
- ✓Ophthalmologic and hearing evaluations
Includes
- hydromicrocephaly
- micrencephalon
Excludes 1 — Do NOT code together
- Meckel-Gruber syndrome (Q61.9)
Code First
- , if applicable, congenital Zika virus disease