ICD-10 Code B35.1: Overview

Medical Billing Codes

Code: B35.1
Description: Tinea unguium
Context: This code is used for cases where a patient is diagnosed with tinea unguium, a fungal infection affecting the nails, commonly known as onychomycosis.

Guidelines for Proper Use

  • Specific Diagnosis for Nail Fungal Infection: Use B35.1 for patients diagnosed with tinea unguium, characterized by a fungal infection of the nails, which can cause nail discoloration, thickening, and brittleness.
  • Accurate Documentation: Ensure the healthcare provider’s documentation clearly indicates a diagnosis of tinea unguium. This diagnosis should be based on clinical findings and, if necessary, confirmed by laboratory tests such as fungal cultures or microscopy.
  • Exclusion of Other Nail Conditions: Do not use B35.1 for other conditions affecting the nails that are not due to a fungal infection, such as psoriasis of the nails or bacterial infections.
  • Differentiation from Other Tinea Infections: Be cautious not to use B35.1 for other types of tinea infections (such as tinea pedis or tinea corporis) that do not affect the nails.
  • Compliance with Coding Standards: Utilize B35.1 in line with clinical documentation and adhere to relevant coding guidelines, including payer-specific requirements.

Common Misuses of B35.1

  • Use for Non-Fungal Nail Disorders: Misuse occurs when B35.1 is used for nail disorders not caused by fungal infection, such as nail dystrophy or trauma-related nail changes.
  • Confusion with Other Tinea Infections: Avoid using B35.1 for fungal skin infections that do not involve the nails.
  • Application to Non-Infectious Conditions: Do not use B35.1 for conditions that mimic fungal nail infections but are non-infectious in nature, such as nail changes due to aging or nutritional deficiencies.