Fibrosis is the universal pathological endpoint of chronic tissue injury — a healing response gone dysregulated, in which activated myofibroblasts (tissue-resident or recruited mesenchymal cells) secrete excessive amounts of extracellular matrix proteins, predominantly type I and III collagen, accumulating as dense, inelastic scar tissue that progressively replaces the functional architecture of the affected organ. Whereas acute wound healing uses fibrosis transiently and resolves it through matrix metalloproteinase (MMP) remodeling, pathological fibrosis is characterized by a self-perpetuating cycle of injury → inflammation → TGF-β₁ signaling → myofibroblast activation → collagen deposition → further injury, leading to irreversible organ stiffening and dysfunction. The three most clinically and coding-significant forms are: idiopathic pulmonary fibrosis (IPF) — a chronic, progressive, devastating interstitial lung disease of unknown etiology characterized by honeycombing on HRCT and usual interstitial pneumonia (UIP) pattern on pathology, with a median survival of only 3-5 years without treatment; hepatic fibrosis — the precirrhotic accumulation of fibrous tissue in the liver from chronic hepatitis, NASH/NAFLD, alcohol, or autoimmune hepatitis, staged F0-F4 on the Metavir scale; and cystic fibrosis (CF) — an autosomal recessive CFTR gene mutation disease in which defective chloride transport causes viscous mucus to obstruct and fibrose the lungs, pancreas, liver, and intestines. Clinical Indicators: ICD-10-CM scatters fibrosis diagnoses across multiple chapters — J84.x (pulmonary/interstitial lung fibrosis), K74.x (hepatic fibrosis/cirrhosis), and E84.x (cystic fibrosis) — each with their own instructional notes, sequencing rules, and Excludes1 boundaries. There is NO generic standalone “fibrosis” ICD-10-CM code applicable across all organ systems; coders must always identify the organ and fibrosis type to select the correct category.
”A fiber, filament, thread; entrails” — a Latin root of uncertain ultimate origin, possibly related to Latin filum (“thread”) or Latin findere (“to split”); in anatomy fibra designated both the fine fibrous structures of muscles and tendons and the abdominal viscera; appears in fibrosis, fibril, fibroma, fibrinogen, fibroblast
“Process, condition, abnormal or pathological state” — the highly productive Greek suffix denoting an ongoing or established pathological process; appears in fibrosis, acidosis, alkalosis, stenosis, cirrhosis
Literally: “A condition or process of fiber/fibrous tissue formation” — a Modern Latin compound first attested in English in 1871 (as documented in Online Etymology Dictionary) describing abnormal fibrous growth in an organ. The hybrid construction pairs the Latin root fibra with the Greek pathological suffix -osis, making fibrosis one of the classic Latin-Greek hybrid medical compounds of nineteenth-century pathological nomenclature (alongside acidosis, alkalosis, and cirrhosis). The specific root fibr- gave rise to a rich family of anatomical and pathological terms: fibril (a microscopic fiber unit), fibrinogen (the clotting protein precursor), fibroblast (the matrix-secreting cell driving fibrosis), and fibroma (a benign fibrous tumor) — making it one of the most generative roots in histopathology.
🔀 ALIASES / ALTERNATE TERMS
Term
Context
Idiopathic pulmonary fibrosis (IPF)
The most clinically significant pulmonary fibrosis subtype — unknown etiology, UIP pattern, progressive, poor prognosis; codes to J84.112 (the specific billable code); requires careful differentiation from other ILD/pulmonary fibrosis subtypes in documentation.
Interstitial lung disease (ILD)
The broad category encompassing IPF, NSIP, COP, and other fibrosing lung conditions; when IPF is specifically documented, J84.112 is used; unspecified ILD maps to J84.9.
Hepatic fibrosis
Liver-specific fibrosis preceding cirrhosis; ICD-10-CM now distinguishes early fibrosis (K74.01) from advanced fibrosis (K74.02) following FY2023 expansion — a critical change from the prior single K74.0 non-billable parent.
Cystic fibrosis (CF)
A genetic multi-organ fibrosing disease from CFTR mutation; maps to the E84.x family — E84.0 (pulmonary), E84.19 (other intestinal), E84.8 (other), E84.9 (unspecified).
Cirrhosis
The end-stage of hepatic fibrosis (F4 Metavir) — functionally distinct in ICD-10-CM; cirrhosis uses K74.60/K74.69 rather than K74.0x; do NOT code both hepatic fibrosis AND cirrhosis for the same liver simultaneously unless both are explicitly documented as co-existing stages.
Pulmonary fibrosis, chronic
May be used clinically for IPF or post-inflammatory/post-radiation pulmonary fibrosis; radiation-induced chronic pulmonary fibrosis maps to J70.1 (excluded from J84.1x family by Excludes1 note).
🔗 RELATED TERMS
Cirrhosis of the liver — K74.60 (unspecified) / K74.69 (other); the end-stage of hepatic fibrosis; ICD-10-CM explicitly excludes cirrhosis from the K74.0x fibrosis codes — do NOT code K74.01/K74.02 when cirrhosis is documented; cirrhosis supersedes fibrosis as the code.
Nonalcoholic steatohepatitis (NASH) — K75.81; the most rapidly growing etiology of hepatic fibrosis in the Western world; ICD-10-CM includes a “Code first” note under K74.0x instructing coders to code the underlying NASH (K75.81) first when it is the documented etiology of the hepatic fibrosis.
Hepatitis C — B18.2 (chronic); a leading cause of hepatic fibrosis and eventual cirrhosis; when both chronic HCV and hepatic fibrosis are documented, code both — the HCV as the etiology and K74.01/K74.02 as the fibrotic complication.
Pneumoconiosis — J60 (coal worker’s) / J62.8 (silicosis); occupational dust-induced pulmonary fibrosis; excluded from the J84.x interstitial lung disease family by instructional notes — occupational fibrotic lung disease uses the J60-J67 range.
Post-radiation pulmonary fibrosis — J70.1; chronic pulmonary fibrosis following radiation therapy; explicitly excluded from the J84.1x family by an Excludes1 note — do NOT use J84.112 for radiation-induced fibrosis.
Sarcoidosis — D86.0 (pulmonary) / D86.9 (unspecified); a granulomatous disease that can progress to pulmonary fibrosis; when both sarcoidosis AND fibrosis are documented, code both — D86.0 as the cause and the relevant J84.x code for the fibrotic sequela if explicitly documented.
Alcoholic fibrosis of the liver — K70.2; alcohol-induced hepatic fibrosis; explicitly excluded from K74.0x by an Excludes1 note — use K70.2 for alcohol-specific hepatic fibrosis, not K74.01/K74.02.
CODING CORNER
🏥 ICD-10-CM CODES
Pulmonary / Interstitial Fibrosis (J84.x Family)
⚠️ ICD-10-CM / Chapter Nuances: J84.1 and J84.11 are NON-BILLABLE parent codes. Use the specific subcode. J84.112 is the specific IPF code — use it ONLY when the physician explicitly documents “idiopathic pulmonary fibrosis” or “IPF.” J84.111 (interstitial pulmonary fibrosis with progressive fibrotic phenotype NOS) was added in FY2022 to capture non-IPF progressive fibrosing ILDs. Post-radiation pulmonary fibrosis (J70.1) is excluded from this family. Occupational/dust-related pulmonary fibrosis uses the J60-J67 range. Do NOT code J84.112 for a patient with “pulmonary fibrosis” NOS from an unspecified etiology — that maps to J84.10 (pulmonary fibrosis, unspecified).
Code
Description
J84.10
Pulmonary fibrosis, unspecified (Use when pulmonary fibrosis is documented but the type/etiology is not specified; do NOT use when IPF is explicitly documented — use J84.112 in that case)
J84.111
Idiopathic interstitial pneumonia, not otherwise specified (NOS category for non-IPF idiopathic interstitial pneumonias — use when ILD/IIP is documented but not specifically classified as IPF, UIP, NSIP, etc.)
J84.112
Idiopathic pulmonary fibrosis (The definitive IPF code — use ONLY when physician explicitly documents “IPF” or “idiopathic pulmonary fibrosis”; the primary diagnosis code supported by nintedanib [Ofev] and pirfenidone [Esbriet/Pirespa] antifibrotic therapy authorization)
J84.170
Interstitial lung disease with progressive fibrotic phenotype in diseases classified elsewhere (FY2022 addition; used for non-IPF progressive fibrosing ILDs — e.g., progressive fibrosing NSIP, systemic sclerosis-associated ILD; nintedanib is approved for this indication; requires the underlying disease coded first)
J84.2
Lymphoid interstitial pneumonia (Billable; use for LIP; excluded from J84.11 family)
J84.9
Interstitial pulmonary disease, unspecified (Last resort; use only when ILD is documented without further specification or subtype)
J70.1
Chronic and other pulmonary manifestations due to radiation (Chronic post-radiation pulmonary fibrosis — Excludes1 from J84.1 family; always use J70.1 for radiation-induced fibrosis and code the radiation adverse effect with T66.x)
Hepatic Fibrosis (K74.x Family)
⚠️ ICD-10-CM / Chapter Nuances: K74.0 is a NON-BILLABLE parent code. The FY2023 update expanded K74.0 into K74.00 (unspecified), K74.01 (early fibrosis), and K74.02 (advanced fibrosis) — a critical change that many coders still miss. Cirrhosis is explicitly Excluded1 from K74.0x — when cirrhosis is documented, use K74.60/K74.69. An instructional note requires coding the underlying liver disease first (e.g., NASH K75.81, viral hepatitis B18.x) when documented.
Code
Description
K74.00
Hepatic fibrosis, unspecified (Use when hepatic fibrosis is documented but the stage/severity is not specified; code the underlying etiology first per “Code first” instructional note)
K74.01
Hepatic fibrosis, early fibrosis (FY2023 addition; corresponds to Metavir F1-F2 staging on liver biopsy; use when physician explicitly documents early fibrosis or mild fibrosis)
K74.02
Hepatic fibrosis, advanced fibrosis (FY2023 addition; corresponds to Metavir F3 staging — bridging fibrosis not yet cirrhosis; use when physician explicitly documents advanced or bridging fibrosis; do NOT use for cirrhosis)
K74.60
Unspecified cirrhosis of liver (End-stage fibrosis [F4]; NOT a fibrosis code — cirrhosis is a distinct Excludes1-separated condition; use when cirrhosis is documented without further specification)
K74.69
Other cirrhosis of liver (Use when cirrhosis is specified as cryptogenic, macronodular, micronodular, or mixed; do NOT use K74.0x)
Cystic Fibrosis (E84.x Family)
⚠️ ICD-10-CM / Chapter Nuances: The E84.x family classifies cystic fibrosis by manifestation system, not by genotype or mutation type. E84 is a NON-BILLABLE parent code. Pulmonary manifestations (E84.0) and intestinal/other manifestations (E84.11, E84.19, E84.8) may be reported together when both are documented and present, since different organ systems are involved. Meconium ileus is excluded from E84.19 and has its own note.
Code
Description
E84.0
Cystic fibrosis with pulmonary manifestations (The primary diagnosis for CF patients managed primarily for lung disease — includes CF-related bronchiectasis, mucus plugging, recurrent pulmonary infections, and CF lung fibrosis; the most common CF code in pulmonology and inpatient encounters)
E84.11
Meconium ileus in cystic fibrosis (Use for neonatal CF presentation with intestinal obstruction from inspissated meconium — a specific and distinct complication code)
E84.19
Cystic fibrosis with other intestinal manifestations (Use for CF-related distal intestinal obstruction syndrome [DIOS], constipation, or exocrine pancreatic insufficiency-related GI manifestations other than meconium ileus)
E84.8
Cystic fibrosis with other manifestations (Use for CF with primarily hepatic, biliary, or musculoskeletal manifestations not captured by E84.0 or E84.1x)
E84.9
Cystic fibrosis, unspecified (Use only when manifestation system is not documented or the CF is newly diagnosed without manifest organ involvement)
🔧 COMMON CPT CODES (Evaluation, Diagnostics & Treatment)
Pulmonary Function Testing (PFT) — IPF / Pulmonary Fibrosis Monitoring
⚠️ CPT Nuance: PFTs are the cornerstone of IPF progression monitoring. In fibrosis, the spirometry pattern is restrictive (reduced FVC, normal or elevated FEV1/FVC ratio) — distinct from the obstructive pattern in COPD. The diffusing capacity (DLCO, 94729) is the most sensitive early marker of IPF and must not be separately billed when included in a comprehensive pulmonary function test panel that already includes it.
CPT Code
Description
94010
Spirometry, including graphic record, total and timed vital capacity, expiratory flow rate measurement(s), with or without maximal voluntary ventilation (Basic spirometry — documents the restrictive pattern [reduced FVC, normal FEV1/FVC] characteristic of pulmonary fibrosis; essential for baseline and serial monitoring)
94060
Bronchodilator responsiveness, spirometry as in 94010, pre- and post-bronchodilator administration (Use when bronchodilator response testing is performed to differentiate obstructive from restrictive disease and to evaluate for a reversible component)
94070
Bronchospasm provocation evaluation, extended, with multiple spirometric determinations (Report for methacholine challenge when bronchospasm/asthma must be excluded in the differential)
94726
Plethysmography for determination of lung volumes and, when performed, airway resistance (Body plethysmography — the gold standard for measuring total lung capacity [TLC]; reduced TLC is the defining feature of a restrictive ventilatory defect in pulmonary fibrosis)
94727
Gas dilution or washout for determination of lung volumes and, when performed, distribution of ventilation and closing volumes (Helium dilution or nitrogen washout lung volume measurement; an alternative to plethysmography for TLC determination)
94729
Diffusing capacity (e.g., DLCO, DLCO/VA) (The most sensitive PFT parameter for IPF monitoring — reduced DLCO reflects alveolar membrane thickening from fibrosis; report separately from spirometry unless included in a bundled panel; a ≥10% decline in FVC or ≥15% decline in DLCO over 6 months is the standard progression threshold triggering antifibrotic therapy initiation)
Bronchoscopy — Diagnosis of Pulmonary Fibrosis
CPT Code
Description
31628
Bronchoscopy, rigid or flexible, including fluoroscopic guidance when performed; with transbronchial lung biopsy(s), single lobe (Transbronchial biopsy for tissue diagnosis in ILD/suspected pulmonary fibrosis; each additional lobe adds 31632 as an add-on)
31632
+Bronchoscopy; with transbronchial lung biopsy(s), each additional lobe (Add-on; list separately in addition to 31628; never alone; report for each additional lobe sampled beyond the first)
31624
Bronchoscopy; with bronchial alveolar lavage (BAL — cytological and microbiological assessment of alveolar cells; often performed alongside transbronchial biopsy in ILD workup to characterize the inflammatory and cellular fibrotic pattern)
31622
Bronchoscopy, rigid or flexible, including fluoroscopic guidance when performed; diagnostic, with cell washing when performed (Diagnostic bronchoscopy base code; report when no biopsy or BAL is performed; if BAL or biopsy is added, use those codes instead — do NOT report 31622 with 31624, 31625, or 31628 for the same procedure)
Liver Biopsy — Hepatic Fibrosis Staging
CPT Code
Description
47000
Biopsy of liver, needle; percutaneous (Percutaneous liver biopsy — the gold standard for hepatic fibrosis staging using Metavir F0-F4 or Ishak 0-6 scales; supports coding K74.01 [early] vs. K74.02 [advanced] vs. K74.60 [cirrhosis] based on pathology report)
47001
+Biopsy of liver, needle; when done for indicated purpose at time of other major procedure (Add-on; report when liver biopsy is performed incidentally alongside another major abdominal procedure; never alone)
47100
Biopsy of liver, wedge (Open or laparoscopic wedge biopsy — larger tissue sample for fibrosis staging when percutaneous biopsy is contraindicated; also used for focal lesion evaluation)
Non-Invasive Liver Fibrosis Assessment
CPT Code
Description
91200
Liver elastography, mechanically induced shear wave (e.g., vibration controlled transient elastography), without imaging, with interpretation and report (FibroScan/transient elastography — non-invasive liver stiffness measurement used as an alternative to biopsy for fibrosis staging; covered by Medicare for chronic HCV and other chronic liver diseases with fibrosis risk; always requires J84.112 / K74.00 etc. as the supporting diagnosis on the claim)
0001M
Infectious disease, HCV, six biochemical assays (FibroTest) (A proprietary serum fibrosis marker panel for HCV-associated hepatic fibrosis — verify individual payer coverage as many commercial plans consider non-invasive fibrosis panels investigational)
Manipulation chest wall, such as cupping, percussing, and vibration to facilitate lung function; initial demonstration and/or evaluation (Chest physiotherapy/airway clearance technique instruction — used for CF mucus clearance management; initial training session)
94668
…subsequent (Report for each subsequent chest PT session after the initial; do NOT use 94668 without a prior 94667 on the claim history)
94640
Pressurized or nonpressurized inhalation treatment for acute airway obstruction for therapeutic purposes and/or for diagnostic purposes such as sputum induction with an aerosol generator, nebulizer, metered dose inhaler or intermittent positive pressure breathing (IPPB) device (Nebulized DNase [dornase alfa/Pulmozyme] treatment for CF mucus clearance — report for each treatment session; verify same-day bundling rules with E&M on the same date)
Significant, separately identifiable E/M service — Append to 99213 / 99214 when the physician performs a separately documented E/M on the same day as PFT testing (94010, 94729) or a bronchoscopy/liver biopsy procedure
Distinct procedural service — Append to 94729 (DLCO) when billed alongside 94726 (plethysmography) to prevent bundling; also use to distinguish 31624 (BAL) from 31628 (transbronchial biopsy) when both are performed in the same bronchoscopy session
Professional component — Append to PFT codes when the physician provides interpretation and report only, without performing the technical component (e.g., when PFTs are performed in a hospital PFT lab and the pulmonologist bills only for reading/interpretation)
Technical component — Append to PFT codes when the facility bills only for the equipment, technician, and supplies without the professional interpretation
Reduced services — Append to a bronchoscopy code when the planned procedure is reduced (e.g., BAL performed but transbronchial biopsy was aborted due to poor oxygenation) without anesthesia termination
Discontinued procedure — Append to a bronchoscopy code when the procedure is terminated after anesthesia induction due to clinical deterioration before the intended procedure is completed
⚠️ Coding Note: The most critical fibrosis coding distinctions span three separate ICD-10-CM chapters, making cross-chapter fluency essential. For pulmonary fibrosis, the highest compliance risk is using J84.112 (IPF) when the record only documents “pulmonary fibrosis” — IPF requires explicit physician documentation of the specific diagnosis; without it, J84.10 (pulmonary fibrosis, unspecified) is the appropriate code. For hepatic fibrosis, the K74.01/K74.02 expansion (FY2023) is still frequently undercoded — when the pathology report specifies Metavir F1/F2 (early) vs. F3 (advanced/bridging), coders must query the physician to confirm documentation supports K74.01 vs. K74.02 rather than defaulting to K74.00. For cystic fibrosis, it is clinically appropriate and ICD-10-CM-compliant to report multiple E84.x codes simultaneously (e.g., E84.0 + E84.19) when both pulmonary AND gastrointestinal manifestations are documented in the same encounter — CF is a multi-system disease and multi-organ manifestation coding is expected. For bronchoscopy, never report 31622 (diagnostic base) alongside 31624 (BAL), 31625 (endobronchial biopsy), or 31628 (transbronchial biopsy) — the therapeutic/biopsy code replaces the diagnostic base code when both are performed in the same session; reporting both is an NCCI bundle violation.
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