What is ICD-10 code A01.03?

A01.03 is the ICD-10-CM diagnosis code for Typhoid pneumonia. This is a serious lung infection caused by the typhoid bacteria (Salmonella typhi) that has spread to the respiratory system. It represents a complication of typhoid fever where the infection affects the lungs and causes pneumonia. A01.03 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. A01.03 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. A01.03 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. A01.03 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for A01.03?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. A01.03 was a payment HCC under V24 (Pneumococcal Pneumonia, Empyema, Lung Abscess) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting A01.03?

This code should only be used when typhoid fever has specifically caused pneumonia as a documented complication; do not use for pneumonia from other causes in a typhoid patient Verify that the clinical documentation explicitly states the pneumonia is related to typhoid infection, as this is a specific manifestation code requiring clear causal relationship Because A01.03 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM A01.03: Typhoid pneumonia

ICD-10-CM Code View

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Code lookupA01.03Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Certain infectious and parasitic diseases (A00-B99) / Intestinal infectious diseases (A00-A09)

A01.03

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

Typhoid pneumonia

This is a serious lung infection caused by the typhoid bacteria (Salmonella typhi) that has spread to the respiratory system. It represents a complication of typhoid fever where the infection affects the lungs and causes pneumonia.

Buddy Insight

Typhoid pneumonia represents a severe extraintestinal complication of Salmonella typhi infection, indicating systemic disease spread to the lungs.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 115

Pneumococcal Pneumonia, Empye...

RAF 0.130

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

Mapped

HCC 115

Pneumococcal Pneumonia, Empye...

RAF 0.030

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

A01Typhoid and paratyphoid fevers

A01.0Typhoid fever

A01.03Typhoid pneumonia

Inclusion Terms

Official

Infection due to Salmonella typhi

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for A01.03 in this effective period.

Related Child Codes

Official

A01.00Typhoid fever, unspecified

A01.01Typhoid meningitis

A01.02Typhoid fever with heart involvement

A01.04Typhoid arthritis

A01.05Typhoid osteomyelitis

Includes

Official

ICD-10-CM does not list Includes notes for A01.03 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for A01.03 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for A01.03 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for A01.03 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for A01.03 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Confirmed or suspected Salmonella typhi infection with documented pulmonary involvement

Chest imaging findings (X-ray or CT) showing pneumonic infiltrates

Clinical correlation establishing the causal link between typhoid fever and pneumonia

Sputum or blood culture results identifying Salmonella typhi

MEAT Support

HCC Buddy guidance

Confirmed or suspected Salmonella typhi infection with documented pulmonary involvement

Chest imaging findings (X-ray or CT) showing pneumonic infiltrates

Clinical correlation establishing the causal link between typhoid fever and pneumonia

Sputum or blood culture results identifying Salmonella typhi

Audit Caution

HCC Buddy guidance

Do not assign A01.03 when pneumonia occurs incidentally in a typhoid patient without a documented causal relationship

Do not code J18.9 separately for the pneumonia — A01.03 is a combination code that captures both the infection and the pulmonary manifestation

Ensure the provider explicitly documents that the pneumonia is due to typhoid, not a concurrent community-acquired pneumonia

Common Mistakes

HCC Buddy guidance

A01.00 (Typhoid fever, unspecified) — Use A01.03 only when pneumonia is a documented complication; A01.00 is for typhoid without specified organ involvement

J15.9 (Unspecified bacterial pneumonia) — Use A01.03 when the pneumonia is specifically caused by typhoid, not J15.9 with a separate typhoid code

A02.22 (Salmonella pneumonia) — A02.22 is for non-typhi Salmonella species causing pneumonia; A01.03 is specifically for S. typhi

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 A01.03 an HCC code?

Yes. A01.03 maps to Pneumococcal Pneumonia, Empyema, Lung Abscess under the V24 model but is not retained in V28.

Code: A01.03
Description: Typhoid pneumonia
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

V24HCC 115, Pneumococcal Pneumonia, Empyema, Lung Abscess

0.130

ESRDHCC 115, Pneumococcal Pneumonia, Empyema, Lung Abscess

0.030

Each model's RAF is its CMS base weight for that model's standard population, so 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 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.

Work A01.03 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for A01.03

For A01.03 to 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 A01.03 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

A01.03 is the ICD-10-CM diagnosis code for typhoid pneumonia. This is a serious lung infection caused by the typhoid bacteria (Salmonella typhi) that has spread to the respiratory system. It represents a complication of typhoid fever where the infection affects the lungs and causes pneumonia. A01.03 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).

Under the older CMS-HCC V24 model, A01.03 maps to Pneumococcal Pneumonia, Empyema, Lung Abscess (HCC 115) with a community, non-dual, aged base RAF weight of 0.130. 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.

This code should only be used when typhoid fever has specifically caused pneumonia as a documented complication; do not use for pneumonia from other causes in a typhoid patient. Because A01.03 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 A01.03 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code should only be used when typhoid fever has specifically caused pneumonia as a documented complication; do not use for pneumonia from other causes in a typhoid patient
•Verify that the clinical documentation explicitly states the pneumonia is related to typhoid infection, as this is a specific manifestation code requiring clear causal relationship

Clinical Significance

Typhoid pneumonia represents a severe extraintestinal complication of Salmonella typhi infection, indicating systemic disease spread to the lungs. This complication significantly increases morbidity and mortality, requiring aggressive antimicrobial therapy and often intensive care management.

Documentation Requirements

✓Confirmed or suspected Salmonella typhi infection with documented pulmonary involvement
✓Chest imaging findings (X-ray or CT) showing pneumonic infiltrates
✓Clinical correlation establishing the causal link between typhoid fever and pneumonia
✓Sputum or blood culture results identifying Salmonella typhi
✓Respiratory symptoms (cough, dyspnea, pleuritic chest pain) in the setting of typhoid fever

Commonly Confused Codes

•A01.00 (Typhoid fever, unspecified): Use A01.03 only when pneumonia is a documented complication; A01.00 is for typhoid without specified organ involvement
•J15.9 (Unspecified bacterial pneumonia): Use A01.03 when the pneumonia is specifically caused by typhoid, not J15.9 with a separate typhoid code
•A02.22 (Salmonella pneumonia): A02.22 is for non-typhi Salmonella species causing pneumonia; A01.03 is specifically for S. typhi