B97.33 Human T-cell lymphotrophic virus, type I [HTLV-I] as the cause of diseases classified elsewhere

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from B97.3 Retrovirus as the cause of diseases classified elsewhere

Excludes1 (never code together)

• Human immunodeficiency virus [HIV] disease (B20)

MS-DRG index

Defines the logic of DRG(s) 865-866 in MDC 18.

Approximate ICD-9-CM (GEMs)

• 079.51 Human T-cell lymphotrophic virus, type I [HTLV-I]

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to B97.33

Back-references to B97

• Type 1 Excludes: B34 Viral infection of unspecified site ("viral agents as the cause of diseases classified elsewhere (B97.-)")
• Use Additional: E06.0 Acute thyroiditis ("code (B95-B97) to identify infectious agent.")
• Use Additional: G06 Intracranial and intraspinal abscess and granuloma ("code (B95-B97) to identify infectious agent.")
• Use Additional: H65 Nonsuppurative otitis media ("infectious agent (B95-B97)")
• Use Additional: I30.1 Infective pericarditis ("code (B95-B97) to identify infectious agent")
• Use Additional: I33.0 Acute and subacute infective endocarditis ("code (B95-B97) to identify infectious agent")
• Use Additional: I40.0 Infective myocarditis ("code (B95-B97) to identify infectious agent")
• Use Additional: J01 Acute sinusitis ("code (B95-B97) to identify infectious agent.")
• Use Additional: J02.8 Acute pharyngitis due to other specified organisms ("code (B95-B97) to identify infectious agent")
• Use Additional: J03.8 Acute tonsillitis due to other specified organisms ("code (B95-B97) to identify infectious agent.")
• Use Additional: J04 Acute laryngitis and tracheitis ("code (B95-B97) to identify infectious agent.")
• Use Additional: J05 Acute obstructive laryngitis [croup] and epiglottitis ("code (B95-B97) to identify infectious agent.")
• Use Additional: J06.9 Acute upper respiratory infection, unspecified ("code (B95-B97) to identify infectious agent, if known, such as:")
• Use Additional: J32 Chronic sinusitis ("infectious agent (B95-B97)")
• Use Additional: J36 Peritonsillar abscess ("code (B95-B97) to identify infectious agent.")
• Use Additional: J37 Chronic laryngitis and laryngotracheitis ("infectious agent (B95-B97)")
• Use Additional: J85 Abscess of lung and mediastinum ("code (B95-B97) to identify infectious agent.")
• Use Additional: J86 Pyothorax ("code (B95-B97) to identify infectious agent.")
• Use Additional: J95.851 Ventilator associated pneumonia ("code to identify the organism, if known (B95.-, B96.-, B97.-)")
• Use Additional: K65 Peritonitis ("code (B95-B97), to identify infectious agent, if known")
• Use Additional: M46.3 Infection of intervertebral disc (pyogenic) ("code (B95-B97) to identify infectious agent.")
• Use Additional: M60.0 Infective myositis ("code (B95-B97) to identify infectious agent")
• Use Additional: M86 Osteomyelitis ("code (B95-B97) to identify infectious agent")
• Use Additional: N10 Acute pyelonephritis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N11 Chronic tubulo-interstitial nephritis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N13.6 Pyonephrosis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N30 Cystitis ("code to identify infectious agent (B95-B97)")
• Use Additional: N34 Urethritis and urethral syndrome ("code (B95-B97), to identify infectious agent.")
• Use Additional: N39.0 Urinary tract infection, site not specified ("code (B95-B97), to identify infectious agent.")
• Use Additional: N41 Inflammatory diseases of prostate ("code (B95-B97), to identify infectious agent.")
• Use Additional: N43.1 Infected hydrocele ("code (B95-B97), to identify infectious agent")
• Use Additional: N45 Orchitis and epididymitis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N47.6 Balanoposthitis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N47.7 Other inflammatory diseases of prepuce ("code (B95-B97), to identify infectious agent.")
• Use Additional: N48.1 Balanitis ("code (B95-B97), to identify infectious agent")
• Use Additional: N48.2 Other inflammatory disorders of penis ("code (B95-B97), to identify infectious agent.")
• Use Additional: N49 Inflammatory disorders of male genital organs, not elsewhere classified ("code (B95-B97), to identify infectious agent")
• Use Additional: N70 Salpingitis and oophoritis ("code (B95-B97), to identify infectious agent")
• Use Additional: N71 Inflammatory disease of uterus, except cervix ("code (B95-B97), to identify infectious agent")
• Use Additional: N72 Inflammatory disease of cervix uteri ("code (B95-B97), to identify infectious agent")
• Use Additional: N73 Other female pelvic inflammatory diseases ("code (B95-B97), to identify infectious agent.")
• Use Additional: N76 Other inflammation of vagina and vulva ("code (B95-B97), to identify infectious agent")
• Use Additional: O03.37 Sepsis following incomplete spontaneous abortion ("code to identify infectious agent (B95-B97)")
• Use Additional: O03.87 Sepsis following complete or unspecified spontaneous abortion ("code to identify infectious agent (B95-B97)")
• Use Additional: O04.87 Sepsis following (induced) termination of pregnancy ("code to identify infectious agent (B95-B97)")
• Use Additional: O07.37 Sepsis following failed attempted termination of pregnancy ("code (B95-B97), to identify infectious agent")
• Use Additional: O08.82 Sepsis following ectopic and molar pregnancy ("code (B95-B97), to identify infectious agent")
• Use Additional: O75.3 Other infection during labor ("code (B95-B97), to identify infectious agent")
• Use Additional: O85 Puerperal sepsis ("code (B95-B97), to identify infectious agent")
• Use Additional: O86 Other puerperal infections ("code (B95-B97), to identify infectious agent")
• Use Additional: P23.0 Congenital pneumonia due to viral agent ("code (B97) to identify organism")

Diagnosis Index entries for B97.33

• Human › T-cell lymphotropic virus › type-1 (HTLV-I) infection › as cause of disease classified elsewhere
• Infection, infected, infective (opportunistic) › retrovirus › as cause of disease classified elsewhere › human › T-cell lymphotropic › type I (HTLV-I)
• Infection, infected, infective (opportunistic) › virus, viral NOS › as cause of disease classified elsewhere › human › T-cell lymphotropic, › type I (HTLV-I)
• Infection, infected, infective (opportunistic) › virus, viral NOS › as cause of disease classified elsewhere › retrovirus › human › T-cell lymphotropic, › type I (HTLV-I)
• Retrovirus, as cause of disease classified elsewhere › human › T-cell lymphotropic › type I (HTLV-I)

Nearby codes

• B97.29 Other coronavirus as the cause of diseases classified elsewhere
• B97.3 Retrovirus as the cause of diseases classified elsewhere
• B97.30 Unspecified retrovirus as the cause of diseases classified elsewhere
• B97.31 Lentivirus as the cause of diseases classified elsewhere
• B97.32 Oncovirus as the cause of diseases classified elsewhere
• B97.33 Human T-cell lymphotrophic virus, type I [HTLV-I] as the cause of diseases classified elsewhere (this code)
• B97.34 Human T-cell lymphotrophic virus, type II [HTLV-II] as the cause of diseases classified elsewhere
• B97.35 Human immunodeficiency virus, type 2 [HIV 2] as the cause of diseases classified elsewhere
• B97.39 Other retrovirus as the cause of diseases classified elsewhere
• B97.4 Respiratory syncytial virus as the cause of diseases classified elsewhere
• B97.5 Reovirus as the cause of diseases classified elsewhere