P04.42 maps to CMS-HCC V28 137. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupP04.42

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain conditions originating in the perinatal period (P00-P96) / Newborn affected by maternal factors and by complications of pregnancy, labor, and delivery (P00-P04)

P04.42

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Newborn affected by maternal use of hallucinogens

A newborn whose mother used hallucinogens (such as LSD) during pregnancy, which may affect the baby's development and health.

Buddy Insight

Maternal hallucinogen use during pregnancy poses unknown but potentially significant risks to fetal development and neonatal health.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 137

Drug Use Disorder, Moderate/S...

Coefficient HCC 137: 0.424 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Context needed

HCC 082

Conditional HHS-HCC mapping: HCC 082 when age < 2. Select the member context before showing a coefficient reference. Metal level and model segment are required for coefficients; no single RAF is shown.

Coefficient needs member context

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

P04Newborn affected by noxious substances transmitted via placenta or breast milk P04.4Newborn affected by maternal use of drugs of addiction P04.42Newborn affected by maternal use of hallucinogens

Inclusion Terms

Official

No inclusion terms are included in this display for P04.42. Check the code and parent instructions in the Code Book.

Excludes 2

Official

newborn affected by other maternal medication (P04.1-)
congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from P00-P96, P04
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from P00-P96, P04
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from P00-P96, P04
neoplasms (C00-D49)Inherited from P00-P96, P04
tetanus neonatorum (A33)Inherited from P00-P96, P04
congenital malformations (Q00-Q99)Inherited from P00-P96, P04
encounter for observation of newborn for suspected diseases and conditions ruled out (Z05.-)Inherited from P00-P96, P04
neonatal jaundice from excessive hemolysis due to drugs or toxins transmitted from mother (P58.4)Inherited from P00-P96, P04
newborn in contact with and (suspected) exposures hazardous to health not transmitted via placenta or breast milk (Z77.-)Inherited from P00-P96, P04

Related Codes

Official

P04.40Newborn affected by maternal use of unspecified drugs of addiction P04.41Newborn affected by maternal use of cocaine P04.49Newborn affected by maternal use of other drugs of addiction

Includes

Official

conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs laterInherited from P00-P96, P04
nonteratogenic effects of substances transmitted via placentaInherited from P00-P96, P04

Excludes 1

Official

No Excludes 1 notes are included in this display for P04.42. Check the code and parent instructions in the Code Book.

Code First

Official

any current condition in newborn, if applicableInherited from P04

Use Additional

Official

No Use Additional Code instructions are included in this display for P04.42. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for P04.42. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of maternal hallucinogen use during pregnancy

Specific hallucinogenic substances if known (LSD, PCP, etc.)

Frequency and timing of maternal use

Clinical observations of newborn behavior

MEAT Support

HCC Buddy guidance

Documentation of maternal hallucinogen use during pregnancy

Specific hallucinogenic substances if known (LSD, PCP, etc.)

Frequency and timing of maternal use

Clinical observations of newborn behavior

Audit Caution

HCC Buddy guidance

Confusing hallucinogens with other psychoactive substances

Using general drug codes when hallucinogen specific

Missing documentation of specific substance class

Incorrectly coding unusual behaviors as separate conditions

Common Mistakes

HCC Buddy guidance

P04.41 — Newborn affected by maternal use of cocaine (cocaine vs hallucinogens)

P04.40 — Newborn affected by maternal use of unspecified drugs of addiction

P04.81 — Newborn affected by maternal use of cannabis

P96.89 — Other specified conditions originating in the perinatal period

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is P04.42 an HCC code?

Yes. P04.42 (Newborn affected by maternal use of hallucinogens) maps to HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.424. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: P04.42 is billable and maps to V28 HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: P04.42
Description: Newborn affected by maternal use of hallucinogens
HCC (V28): HCC 137 — Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications
RAF reference coefficient: 0.424
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 137, Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications

0.424

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work P04.42 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for P04.42

For P04.42, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

P04.42 is the ICD-10-CM diagnosis code for newborn affected by maternal use of hallucinogens. A newborn whose mother used hallucinogens (such as LSD) during pregnancy, which may affect the baby's development and health. P04.42 sits in the ICD-10-CM chapter for certain conditions originating in the perinatal period (p00-p96), within the section covering newborn affected by maternal factors and by complications of pregnancy, labor, and delivery (p00-p04).

Under the CMS-HCC V28 risk adjustment model, P04.42 maps to Drug Use Disorder, Moderate/Severe, or Drug Use with Non-Psychotic Complications (HCC 137) with a source-labeled community, non-dual, aged reference coefficient of 0.424. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This code indicates maternal substance use history; document the specific hallucinogen if known for complete clinical picture. For P04.42, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for P04.42 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code indicates maternal substance use history; document the specific hallucinogen if known for complete clinical picture
•Use with other perinatal codes to describe any resulting neonatal conditions or complications

Clinical Significance

Maternal hallucinogen use during pregnancy poses unknown but potentially significant risks to fetal development and neonatal health. These newborns require careful observation for unusual behavioral patterns and potential developmental complications, though specific effects may be difficult to predict.