ICD-10 Code R74.01: Elevation of Liver Transaminase Levels

Key Takeaways

ICD-10 Code R74.01 is the billable code for elevation of liver transaminase levels (ALT and/or AST) without a confirmed diagnosis.

Use R74.01 only when no definitive liver disease has been established – once a diagnosis is confirmed, transition to the appropriate specific code.

R74.01 has been a valid billable code since the implementation of ICD-10-CM on October 1, 2015 (FY2016) and remains valid for FY2025/FY2026 HIPAA-covered claim submissions.

Pabau’s claims management software helps practices track lab-flagged findings and link them to accurate diagnostic codes at the point of billing.

A patient’s routine bloodwork comes back with ALT at three times the upper limit of normal. There is no confirmed hepatitis diagnosis, no established NAFLD, no documented cirrhosis. What code goes on the claim? For many coders and clinicians, this scenario ends in a denial or an incorrect specificity flag. ICD-10 Code R74.01 is precisely the code designed for this situation: an isolated lab abnormality that warrants documentation and monitoring, but has not yet resolved into a definitive diagnosis.

This reference covers the official code description, clinical context, coding and sequencing rules, related codes, documentation standards, and billing considerations for R74.01 – the information coders and clinicians need to submit clean claims and maintain audit-ready records.

ICD-10 Code R74.01: Definition and Clinical Description

Official description: Elevation of levels of liver transaminase levels. R74.01 sits within the ICD-10-CM chapter R00-R99 (Symptoms, Signs, and Abnormal Clinical and Laboratory Findings) under block R70-R79 (Abnormal findings on examination of blood, without diagnosis). The code has been valid since the implementation of ICD-10-CM on October 1, 2015 (FY2016) and has had no changes in any subsequent fiscal year through FY2026.

According to the official ICD-10-CM tabular list, R74.01 explicitly includes two clinical conditions: elevation of levels of alanine transaminase (ALT) and elevation of levels of aspartate transaminase (AST). Both enzymes are captured under this single code, making it applicable whether only ALT is elevated, only AST is elevated, or both are elevated simultaneously.

Transaminases are intracellular enzymes released into the bloodstream when hepatocytes are damaged or inflamed. Elevated readings on a liver function panel – without a known underlying cause – represent exactly the clinical scenario R74.01 was designed to capture. Clinicians ordering repeat panels, monitoring statin-related hepatotoxicity, or investigating incidental lab findings during routine wellness visits will encounter this code frequently. Practices using lab management software can flag these abnormal results automatically, reducing the risk that elevated transaminases are documented but never coded.

When to Use ICD-10 Code R74.01

The defining criterion for R74.01 is the absence of a confirmed liver diagnosis. Under ICD-10-CM guidelines, codes from the R chapter are symptom and abnormal finding codes – they apply when the underlying cause has not been established. As soon as a definitive condition is documented, the appropriate etiology-specific code replaces R74.01.

• Correct use: ALT or AST elevated on routine bloodwork, cause under investigation, no confirmed diagnosis documented in the record
• Correct use: Monitoring a patient on hepatotoxic medications (statins, methotrexate, isoniazid) with asymptomatic transaminase elevation, no definitive DILI diagnosis established
• Correct use: Incidental finding of elevated liver enzymes during a wellness visit, follow-up testing ordered, no liver disease confirmed
• Incorrect use: Patient has confirmed viral hepatitis B (use B18.1), alcoholic hepatitis (K70.10), or non-alcoholic steatohepatitis (K75.81) – these are definitive diagnoses
• Incorrect use: Coding R74.01 after a liver biopsy confirms NAFLD or cirrhosis – transition to the specific diagnosis code

Functional medicine and integrative primary care practices that frequently order comprehensive metabolic panels will encounter R74.01 as part of ongoing monitoring protocols. Functional medicine software that integrates lab tracking with clinical notes makes the transition from monitoring code to definitive diagnosis code more traceable. For broader situational context on how abnormal finding codes work across different clinical presentations, the situational anxiety ICD-10 code article illustrates similar coding logic for symptom-level diagnoses.

Coding Guidelines and Sequencing Rules

Several sequencing and specificity rules govern correct use of R74.01. Misapplying these rules is one of the most common reasons claims with this code are returned or audited.

Principal vs. Secondary Diagnosis

R74.01 can be used as a principal diagnosis when the elevated transaminase finding is the primary reason for the encounter – for example, a visit specifically to review and discuss an abnormal lab result. It can also appear as a secondary diagnosis when the elevation is incidentally noted during a visit with a different primary reason. Payer policies on whether R74.01 is accepted as a primary diagnosis vary, so verifying coverage policies before submission is advisable.

Practices using digital intake forms linked to clinical documentation can capture the reason for visit clearly at the point of intake, making it easier to establish whether the transaminase finding drives the encounter or is secondary to another condition.

Parent Hierarchy: R74 > R74.0 > R74.01

R74.01 sits within a two-level parent hierarchy. R74 (Abnormal serum enzyme levels) is the top-level non-billable category. R74.0 (Nonspecific elevation of levels of transaminase and lactic acid dehydrogenase [LDH]) is the immediate parent of R74.01 and is also non-billable. Claims submitted with either R74 or R74.0 will be rejected as lacking sufficient specificity. The billable child codes under R74.0 are:

• R74.01 – Elevation of levels of liver transaminase levels (ALT and/or AST)
• R74.02 – Elevation of levels of lactic acid dehydrogenase (LDH)
• R74.8 – Abnormal levels of other serum enzymes
• R74.9 – Abnormal serum enzyme level, unspecified

Always use R74.01, never the parent R74, when the clinical finding is specifically elevated ALT or AST. R74.9 should only be used when the specific enzyme involved is genuinely unknown – which is clinically rare given that modern metabolic panels specify each enzyme individually.

Related ICD-10 Codes and Crosswalks

Coders working with liver enzyme abnormalities need to know the landscape of adjacent codes to ensure they are selecting the most specific option available. The table below outlines the most relevant related codes for transaminase elevation scenarios.

When drug-induced liver injury (DILI) is suspected but not yet confirmed, continue using R74.01 alongside a medication code (Z79.899 or specific drug code). Once DILI is confirmed as the cause, transition to the appropriate toxic liver disease code (K71 series). For reference on how coding specificity works across other abnormal diagnostic findings, see these ICD-10 codes for other diagnostic findings as a parallel example of how the R00-R99 chapter governs symptom-level reporting.

Documentation Requirements for Accurate R74.01 Coding

Claims submitted with R74.01 require clinical documentation that supports the finding and demonstrates why a definitive diagnosis was not established. Auditors reviewing these claims look for three things: the lab result itself, the clinical context, and evidence of follow-up planning.

• Lab result documentation: The actual ALT and/or AST values should appear in the clinical note, with the reference range and the date the result was received
• Clinical context: A brief notation explaining why the finding is being coded – incidental discovery, monitoring visit, or chief complaint of abnormal labs
• Differential or plan: Documentation that a definitive diagnosis has not been established, with a plan for further workup (repeat LFTs, imaging, hepatology referral)
• Medication review: If the patient is on hepatotoxic medications, note this in the record and code the medication separately (Z79 series)
• Negative exclusions: Where appropriate, noting that viral hepatitis, alcoholic liver disease, and other common causes have been excluded or are under investigation

Clinicians who use AI-assisted clinical documentation can capture these elements more consistently at the point of care, reducing the gap between what was observed and what appears in the billing record. A structured client record system that links lab results directly to clinical notes and encounter diagnoses also reduces the risk that an elevated transaminase result is filed without a corresponding billable code. For context on how documentation specificity applies to other hemorrhagic and vascular findings, the intraparenchymal hemorrhage ICD-10 codes guide illustrates the same audit-readiness principles.

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Billing and Reimbursement Considerations

R74.01 is a fully billable ICD-10-CM code, valid for HIPAA-covered transactions submitted from October 1, 2025 onward under FY2026 guidelines. According to ICD List, R74.01 is confirmed billable and specific for claim submission purposes. The billing landscape for this code has several nuances that directly affect reimbursement outcomes.

Primary Diagnosis Acceptance

Whether payers accept R74.01 as a primary diagnosis depends on the clinical context and the specific payer’s policies. Medicare and most commercial payers will accept it as a primary code when the encounter is specifically for evaluation of an abnormal lab result. Practices that submit R74.01 as a primary diagnosis without clear documentation that the abnormal finding was the reason for the visit may face medical necessity denials. Always verify payer-specific local coverage determinations (LCDs) before assuming coverage.

Common CPT Code Pairings

R74.01 typically appears on claims paired with evaluation and management codes or lab panel codes. Common pairings include:

• 99213/99214: Office visit for review of abnormal lab results with moderate complexity medical decision-making
• 80076: Hepatic function panel (if ordered at the same visit)
• 80053: Comprehensive metabolic panel (if the transaminase elevation was found incidentally)
• 82150: Amylase (when ruling out pancreatic causes of enzyme elevation)

Practices managing high volumes of lab-driven visits benefit from claims management software that can apply coding rules consistently across similar encounter types, reducing the manual review burden on billing staff. The CMS ICD-10 codes page provides the official FY2026 tabular list and coding guidelines that govern R74.01 claim submission requirements.

Expert Picks

Expert Picks

Need guidance on interpreting lab biomarkers without overclaiming? Interpreting Biomarkers Without Overpromising provides a clinical framework for communicating abnormal findings to patients with appropriate clinical nuance.

Looking for how to handle complex metabolic panel interpretation? Organic Acids Test Interpretation covers lab result documentation and clinical note standards for functional and integrative medicine practices.

Want to reduce claim denials linked to documentation gaps? Pabau Claims Management helps practices link diagnosis codes to supporting documentation and automate resubmission workflows.

Conclusion

Elevated transaminases without a confirmed cause are a common clinical scenario – and R74.01 is the correct code for exactly that situation. The critical discipline is knowing when to use it and when to transition to a definitive diagnosis code as the clinical picture becomes clearer.

Pabau’s lab management and claims management tools help practices close the gap between lab findings and billing accuracy – so that every R74.01 encounter is documented, coded, and submitted with the specificity payers require. To see how Pabau supports coding accuracy across your practice, book a demo.

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