Medical Coding Haemophilus Influenzae

by  Janine Mothershed
Jun 9th, 2025

Here's a clear and thorough guide for medical coding and billing for Haemophilus influenzae (H. influenzae) — not to be confused with the flu (influenza virus). This bacterium can cause serious invasive diseases like meningitis, epiglottitis, pneumonia, and sepsis.

Common ICD-10 Diagnosis Codes:

Tip: Always choose a specific site code (like J14 or G00.0) when available instead of A49.2 (nonspecific site).

Vaccination Coding for Hib (Haemophilus influenzae type b)

Vaccination is specifically for Hib, primarily in pediatric populations.

CPT Codes – Hib Vaccine:

Vaccine Administration Codes:

For information on medical coding flu vaccines, visit:  https://codingclarified.com/medical-coding-of-flu-vaccines/

The diagnosis code for immunization is Z23 – Encounter for immunization.

Billing Tips

When treating H. influenzae infection:

• Use the most specific ICD-10 code (e.g., J14 for pneumonia).
• Document organism identification (via culture or PCR).
• If multiple complications are present, code each condition (e.g., meningitis and sepsis).

When billing for Hib vaccine:

• Use Z23 as the primary diagnosis.

• Ensure proper documentation of:

  • Manufacturer, lot number

  • Route, site of administration

  • Parent/guardian consent

  • Counseling (if billing 90460/90461)

Clinical and Coding Scenarios

Example 1: Hib Meningitis

• ICD-10: G00.0

• Supporting codes: Fever (R50.9), seizures (R56.9) if present

Example 2: Hib Pneumonia

• ICD-10: J14

• Avoid generic pneumonia codes unless cause is unknown

Example 3: Well-child visit with Hib vaccine

• CPT: 90648

• Admin: 90460 (if counseling is given)

• ICD-10: Z23 + Z00.129 (routine child visit)

Compliance and Documentation Tips

• Use lab confirmation if billing for a specific organism (especially G00.0 or A41.3).

• Avoid generic infection codes when a specific bacterial etiology is documented.

• When giving the Hib vaccine:

  • Include documentation of education/counseling if using 90460.

  • Include Z23 in diagnosis.

• Check payor-specific policies: Some Medicaid/CHIP plans have unique guidelines for vaccine billing.

Summary Coding Table

Condition - ICD-10 Code - CPT Code (if vaccinated)

Janine Mothershed is the founder and CEO of Coding Clarified, an innovative online medical coding school committed to transforming lives through flexible, high-quality career training. A Certified Professional Coder (CPC) and licensed AAPC instructor, Janine brings over a decade of experience in healthcare administration, medical coding, and workforce development.

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