ICD-10 Code K71.2: Toxic liver disease with acute hepatitis

Key Takeaways

K71.2 (Toxic liver disease with acute hepatitis) is a billable ICD-10-CM diagnosis code effective for FY 2026 claims.

An additional code from T36-T50 (with fifth or sixth character 5) is required to identify the causative drug when documenting an adverse effect.

K71.2 is frequently confused with K71.1 (hepatic necrosis) and K71.3 (chronic persistent hepatitis); the clinical timeline and histology determine the correct code.

Practice management software like Pabau helps gastroenterology and hepatology practices attach the correct companion codes and reduce K71.2 claim denials.

ICD-10 Code K71.2 is the billable ICD-10-CM code for toxic liver disease with acute hepatitis, an inflammatory reaction of the liver caused by a drug, chemical, or toxic substance rather than a viral or autoimmune process.

The code rarely stands alone on a claim: payers expect a companion code identifying the causative drug, and leaving it off is the most common reason K71.2 claims are rejected.

ICD-10 Code K71.2 falls within the K71 category (Toxic liver disease), maintained by the CDC/NCHS ICD-10-CM classification system and updated annually for the US clinical setting. Histologically, the pattern resembles viral hepatitis, with lobular disarray, hepatocyte necrosis, and inflammatory infiltrate, but the clinical timeline is tied directly to drug exposure.

Correct use of K71.2 requires the clinician to have documented both the acute nature of the hepatitis and its toxic or drug-induced etiology in the medical record. Without both elements, a more general code such as K71.9 (Toxic liver disease, unspecified) may be more appropriate, though it carries less specificity for reimbursement purposes.

Drug-induced liver injury and the ICD-10 code K71.2

Drug-induced liver injury (DILI) is the umbrella term for liver damage caused by medications, chemicals, or toxins. The K71 category splits it into two patterns: drug-induced toxic (predictable) liver disease, which is dose-dependent, and drug-induced idiosyncratic (unpredictable) liver disease, which is not tied to dose. K71.2 sits inside that group.

K71.2 is the code to use when the record documents an acute inflammatory pattern tied to drug exposure, whether the clinical note calls it drug-induced liver injury, drug-induced hepatitis, drug-induced hepatotoxicity, or toxic hepatitis. These terms describe the same injury pattern, so they all map to K71.2, provided the timeline is acute rather than chronic.

Whichever term the note uses, K71.2 rarely travels alone. Every DILI claim still needs a companion T-code to name the causative agent, and the acute pattern has to be documented to separate K71.2 from the cholestatic, necrotic, and chronic presentations in the rest of the K71 family.

Liver injury tied to a systemic disease rather than a drug or toxin falls outside K71 entirely and maps to K77 instead.

Billable status and coding conventions for K71.2

K71.2 is a fully billable ICD-10-CM code, meaning it provides sufficient specificity to justify admission to an acute care hospital when used as a principal diagnosis. No additional sub-codes extend from K71.2 itself; the code is at its terminal node in the hierarchy.

The AAPC Codify ICD-10-CM reference and the official tabular list both confirm two mandatory coding conventions at the K71 category level that apply directly to K71.2:

• Use additional code for adverse effect, if applicable, to identify the drug (T36-T50 with fifth or sixth character 5). This applies when the patient suffered an adverse reaction to a correctly prescribed and administered drug.
• Code first poisoning due to drug or toxin, if applicable (T36-T65 with fifth or sixth character 1-4). This applies when the exposure resulted from overdose, wrong drug, or wrong route of administration.

The distinction between an adverse effect and a poisoning changes code sequencing entirely, and it is one of the areas where documentation most often falls short. Structured patient intake software helps capture the exposure context at the point of care rather than during retrospective chart review.

Excludes notes at the K71 category level

Two Excludes2 notes apply to the entire K71 category, including K71.2. Excludes2 means the excluded condition is not part of K71.2 but may be coded simultaneously if both are documented:

• Alcoholic liver disease (K70.-): A separate category entirely. If the patient has both drug-induced hepatitis and alcoholic liver disease, both code families may be reported, but the etiology must be clearly distinguished in the clinical record.
• Budd-Chiari syndrome (I82.0): Hepatic vein thrombosis is a vascular condition distinct from toxic hepatocellular injury. Code separately when both are present.

Other specified liver diseases without a toxic or drug-induced cause, such as focal hepatic lesions, are captured under K76.89 rather than K71.2.

A common documentation mistake is failing to distinguish alcoholic from drug-induced liver injury when a patient uses both alcohol and hepatotoxic medications. Clinicians who rely on structured patient record templates are less likely to leave this ambiguity unresolved at discharge.

K71.2 sequencing rules: Adverse effect vs. poisoning

Getting sequencing right for K71.2 is where most coder errors occur. The clinical scenario determines which code leads the claim and which serves as the secondary diagnosis.

When the exposure scenario is an adverse effect, K71.2 sequences first. When it is a poisoning, the T-code for the responsible substance sequences first, and K71.2 becomes the manifestation. This distinction follows the CMS ICD-10-CM guidelines, Section I.C.19 of the Official Guidelines for Coding and Reporting.

How K71.2 differs from adjacent codes in the K71 category

The K71 category has multiple subcodes that describe different clinical presentations of toxic liver disease. Selecting K71.2 over a sibling code requires clear documentation of the hepatitis pattern and its acuity.

The K71.2 vs K71.1 distinction is the most clinically consequential. Both present acutely, but K71.1 requires documented hepatic necrosis, which is typically evident on biopsy or imaging showing liver volume loss and failure markers. Percutaneous liver biopsy, billed under CPT 00702, is the procedure most often ordered to confirm or rule out necrosis.

K71.2 does not require necrosis; the acute hepatitis pattern with elevated transaminases and a compatible drug exposure timeline is sufficient. Gastroenterology and hepatology practices that use structured claims management software flag these distinctions during charge capture rather than at remittance.

MS-DRG mapping for ICD-10 Code K71.2

For inpatient hospital billing, K71.2 groups within the MS-DRG v43.0 liver disease groupings maintained by CMS, specifically DRG 441, 442, and 443 (Disorders of liver except malignancy, cirrhosis, or alcoholic hepatitis).

Which of the three applies depends on whether a major complication or comorbidity (MCC) or a complication or comorbidity (CC) is documented, and on whether hepatic failure is also coded.

When cirrhosis rather than acute hepatitis is the documented pattern, the case routes to K74.60 and a different DRG set, not the 441-443 family.

Practices billing under HIPAA-mandated ICD-10-CM requirements should verify the current-year MS-DRG grouper outputs directly, since DRG relative weights and assignment logic are updated annually in the CMS IPPS Final Rule. A DRG lookup tool can offer a useful starting reference, though the authoritative source remains the CMS Grouper software.

When acute hepatic failure (K72.00) is coded alongside K71.2 as a secondary diagnosis, it typically qualifies as a major complication or comorbidity (MCC), which moves the claim to DRG 441 within the same 441/442/443 liver-disease family rather than a separate liver failure grouping.

Documenting both conditions when clinically supported increases appropriate reimbursement and reduces under-coding. This is a common point of under-coding in hepatology practices, particularly those that have not implemented EHR and billing workflows.

Reduce K71.2 claim denials with better documentation workflows

Pabau helps gastroenterology and hepatology practices capture drug exposure context at the point of care, attach the correct T-code companions, and submit cleaner claims from day one.

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ICD-9-CM crosswalk for K71.2

For practices that still reference legacy data or work with payers using ICD-9-CM for historical claims analysis, K71.2 converts approximately to ICD-9-CM code 573.3 (Hepatitis, unspecified). This is an approximate crosswalk: 573.3 is broader and does not capture the toxic etiology or the acute pattern with the same specificity that K71.2 provides.

Researchers and health information managers working with Medicare claims data will find this transition covered in ResDAC’s Medicare ICD guidance. The broader ICD-9 mapping means that historical cohort studies using 573.3 will include cases of infectious, drug-induced, and idiopathic hepatitis that would now be coded separately under ICD-10.

For billing teams reviewing denied historical claims, the broader ICD-9 crosswalk reflects a genuine difference in granularity between the two classification systems, rather than a documentation problem. Practices with HIPAA-compliant medical record management will have the documentation depth needed to support the more specific ICD-10 code.

Documentation requirements for K71.2 claims

Payers reviewing K71.2 claims look for specific documentation elements. Missing any one of them is sufficient grounds for a medical necessity denial. The clinical record should contain:

• Named causative drug or toxin: The specific agent (e.g., amoxicillin-clavulanate, methotrexate, isoniazid) must be documented by the treating clinician, not inferred from the medication list by the coder.
• Onset and duration: Acute hepatitis has a distinct onset. The note should specify when symptoms began relative to drug initiation or dose change.
• Laboratory pattern: Elevated ALT/AST, typically transaminase-predominant and sometimes charted as drug-induced transaminitis. A note using that label still resolves to K71.2 once the acute hepatitis pattern is confirmed. Bilirubin and ALP levels help characterize cholestatic vs. hepatocellular patterns. Isolated transaminase elevation without a confirmed hepatitis pattern codes to R74.01 instead.
• Causal relationship statement: The physician should explicitly state that the hepatitis is drug-induced or toxic in origin, not simply list it in the differential diagnosis.
• Adverse effect vs. poisoning determination: Was the drug correctly prescribed and taken as directed? This determines T-code assignment and sequencing.

The lab draws that generate these values are typically billed under 36415. Practices formalizing these documentation standards can start from a HIPAA privacy policy template and adapt the causative-agent field to their own EHR.

Practices using clinical documentation software to standardize these fields see fewer queries from coders. The pattern applies equally to hepatology as it does to other specialties coding behavioral or neurological conditions.

Common payer denial reasons for ICD-10 Code K71.2

Understanding why K71.2 claims are denied is as important as knowing how to code the diagnosis correctly. The most common denial patterns fall into three categories.

Missing T-code companion

K71.2 submitted without a corresponding adverse effect or poisoning code from the T36-T65 range is the leading cause of denial. Payers treat the absent T-code as incomplete coding and may down-code to K71.9 or request additional documentation before processing. The same missing-companion-code pattern drives denials for 97014 and other codes that require a paired modifier or diagnosis.

Etiology not supported in clinical notes

When a coder assigns K71.2 based on a lab result showing elevated transaminases and a drug on the medication list, but the physician note never states the hepatitis is drug-induced, the claim lacks physician documentation support. This is a query-generating scenario: the coder should seek clarification before coding, not after submission.

Wrong code selected for clinical presentation

K71.2 requires an acute hepatitis pattern. When the hepatitis has persisted beyond the six-month threshold, K71.3 or K71.5 is more appropriate. Submitting K71.2 for a presentation with a documented nine-month history may trigger a clinical review. Similarly, if hepatic necrosis is present on biopsy, K71.1 is the correct code.

Practices that build these clinical decision points into revenue cycle management catch wrong-code selections before submission rather than at the denial stage. The principle holds across all specialty-specific code families: internal review against the clinical note is always faster than appeals.

Conclusion

K71.2 is precise where ICD-9 was vague. Drug-induced acute hepatitis now has its own code, its own sequencing rules, and its own documentation requirements. Getting it right means capturing the causative agent, the exposure timeline, and the clinical pattern in the physician note before the chart ever reaches a coder.

Pabau’s claims management software gives gastroenterology and hepatology practices a structured way to attach T-code companions at charge capture, flag sequencing requirements, and track denial patterns by diagnosis code. To see how it fits your billing workflow, book a demo.

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