Elevated ALT and AST levels show up in routine panels for patients with no pain, no jaundice, and no prior liver diagnosis. Multiple perspectives matter at this point because the clinical meaning (possible hepatocellular injury), the documentation burden (what the provider must state), and the billing risk (what the payer accepts) pull in different directions. Clear coding starts with one fact: ICD-10-CM does not code the word “transaminitis.” It codes the measurable finding. This blog focuses on USA-based ICD-10-CM workflows and uses the code that payers and code sets align with for isolated ALT/AST elevation: R74.01.
What “Transaminitis” Means in Clinical Documentation
Multiple perspectives matter because “transaminitis” functions as shorthand in clinical speech, not as a diagnosis label in ICD-10-CM. Transaminitis refers to elevated transaminase enzymes in blood testing, primarily:
- ALT (alanine aminotransferase)
- AST (aspartate aminotransferase)
ALT and AST live inside cells. Hepatocellular irritation or injury increases membrane leakage, raising serum levels. ALT tracks liver injury more directly than AST, since AST rises with liver injury and non-hepatic injury such as skeletal muscle disorders. Clinical references describe severity bands using multiples of the upper limit of normal (ULN), such as <2× ULN, 2–5× ULN, 5–15× ULN, and >15× ULN, with different diagnostic urgency at higher tiers.
A cause-based evaluation often starts with pattern recognition and risk review. Hepatology education materials emphasize historical factors like alcohol intake, medication lists, herbal products, viral hepatitis risk, metabolic risk, and physical signs of chronic liver disease.
Why ICD-10 Does Not List “Transaminitis” as a Code Title
Multiple perspectives matter because ICD-10-CM prioritizes classified findings and diagnoses, not informal clinical terms. Transaminitis describes a lab pattern, not an etiology. ICD-10-CM places that pattern under abnormal clinical and laboratory findings, which is why the correct code uses measurable language.
The practical result: providers search the code set for “transaminitis,” pick a nearby “abnormal enzyme” option, and end up with a code that does not defend liver-specific medical necessity.
The Correct ICD-10-CM Code for Transaminitis
Multiple perspectives matter because the “right” code depends on the level of certainty. A confirmed disease needs a disease code. An isolated lab abnormality needs an abnormal-finding code.
R74.01 – Elevation of liver transaminase levels is the ICD-10-CM code that matches elevated ALT/AST when a definitive liver diagnosis has not been established.
Coding teams see R74.01 used to support:
- Repeat hepatic function panels
- hepatitis serologies
- iron studies
- abdominal ultrasound orders
- follow-up E/M for trend review
ICD-10-CM index entries show R74.01 as the destination for “elevation (ALT).”
Why R74.01 Gets Denials Even When It Is Correct
Multiple perspectives matter because a correct code still fails when documentation misses 1 of the payer-facing elements: severity, context, or plan.
Denial trigger 1: no numeric lab values
Claims reviewers often see “elevated LFTs” in the assessment with no ALT/AST numbers. A chart without values weakens the link between abnormal findings and follow-up testing.
Denial trigger 2: no assessment language that matches R74.01
R74.01 describes elevated liver transaminases. Notes that focus only on “abnormal liver function,” “elevated enzymes,” or “abnormal labs” without naming ALT/AST invite code drift.
Denial trigger 3: plan lacksa medical-necessity bridge
Orders like ultrasound, hepatitis B testing, hepatitis C testing, or medication changes need a sentence that connects the abnormality to the plan.
Denial trigger 4: code never transitions to the diagnosis
R74.01 is not a permanent label once fatty liver disease, hepatitis, alcoholic liver disease, drug-induced injury, or other diagnoses become established.
ICD-10-CM guidance states symptom/sign codes are acceptable when a related definitive diagnosis has not been established. The same guidance discourages coding symptoms as “extra” once the definitive diagnosis exists and the symptom is integral to it.
R74.01 vs R89.0: Right Choice
Multiple perspectives matter because both codes mention “abnormal enzymes,” but they describe different specimen contexts.
R74.01 (liver blood chemistry focus)
- Targets elevated liver transaminases
- supports liver-focused workups
R89.0 (non-blood, non-liver specimen focus)
R89.0 — Abnormal level of enzymes in specimens from other organs, systems,, and tissues is intended for abnormal enzyme findings in specimens outside the “blood without diagnosis” section, such as synovial fluid or other tissue specimens, ns depending on the clinical scenario.
R89.0 reduces clarity for a payer reviewing a liver enzyme workup because it does not explicitly describe ALT/AST elevation in serum.
“Is R74.01 Billable?” and What Billers Actually Need to Know
Multiple perspectives matter because “billable” means “valid code,” while reimbursement depends on coverage rules and documentation quality.
R74.01 is a specific, billable ICD-10-CM diagnosis code.
Payment still depends on:
- the billed service (E/M level, lab panel, imaging CPT)
- payer policy (frequency limits, diagnosis-to-test edits)
- documentation alignment (assessment-to-plan consistency)
“Can R74.01 Be Primary?”
Multiple perspectives matter because inpatient “principal diagnosis” rules differ from outpatient “first-listed diagnosis” rules, and payer audits often focus on diagnosis sequencing logic.
ICD-10-CM guidance states that codes that describe signs and symptoms are acceptable for reporting when a related definitive diagnosis has not been established.
That guidance supports R74.01 as first-listed when elevated transaminases represent the reason for the visit, and no diagnosis has been confirmed.
R74.01 becomes weaker as first-listed once documentation identifies an established etiology that has its own code. A confirmed condition should sequence ahead of the abnormal finding
Clinical Causes Where R74.01 is Not a Choice
Multiple perspectives matter because coders need cause categories that predict which diagnosis code will replace R74.01. Primary care literature lists common etiologies for mildly elevated transaminases, including NAFLD and alcohol-related liver disease, with other causes such as drug-induced liver injury, hepatitis B, hepatitis C, hemochromatosis, autoimmune hepatitis, and Wilson disease. Extrahepatic causes include thyroid disorders, celiac disease, hemolysis, and muscle disorders.
A practical way to document cause workup uses 4 buckets:
- Metabolic liver disease: obesity, insulin resistance, dyslipidemia, metabolic syndrome
- Alcohol-associated injury: high intake patterns, binge episodes, withdrawal history
- Viral hepatitis: hepatitis B risk factors, hepatitis C risk factors, exposure history
- Drug or toxin injury: acetaminophen use, statins, antifungals, supplements, bodybuilding products
Documentation Checklist for R74.01
Multiple perspectives matter because coders code what providers document, while payers reimburse what documentation proves.
Use this checklist in the assessment and plan:
Required elements
- ALT value and AST value with units and collection date
- Symptom review tied to liver disease red flags: jaundice, dark urine, pruritus, RUQ pain, nausea, weight loss
- Risk review: alcohol intake, medication list, supplement list, viral exposure risks, metabolic risks
- Plan statement that links R74.01 to the workup
Preferred phrasing that matches the code
- “Elevated ALT and AST on labs dated //____, ALT ___ U/L, AST ___ U/L.”
- “Assessment: elevation of liver transaminases without established etiology.”
- “Plan: repeat hepatic panel in ___ weeks, order hepatitis B testing and hepatitis C testing, order ultrasound, review medication exposures.”
Phrases that increase audit friction
- “Rule out liver disease” without a defined plan.
- “Abnormal labs” with no enzyme names and no values
- “Transaminitis” with no link to ALT/AST
ICD-10-CM guidance supports coding to the level of certainty known for the encounter. Documentation that states uncertainty plus an action plan fits that rule.
Coding Measures That Reduce Denials
Multiple perspectives matter because coding decisions are not clinical guesses. Coding follows ca ertainty level.
Step 1: Confirm the finding
- ALT and AST are listed in the record with values
Step 2: Check for an established diagnosis
- imaging-confirmed fatty liver
- documented viral hepatitis diagnosis
- documented alcohol-associated liver disease
- documented drug-induced liver injury
Step 3: Assign the code that matches certainty
- no diagnosis established → R74.01
- diagnosis established → assign the diagnosis code and stop leading with R74.01
Step 4: Update the problem list and claim sequencing
- R74.01 was removed or moved behind the definitive diagnosis once confirmed
Real-World Example With Proper Sequencing
Multiple perspectives matter because examples show how documentation and coding move together.
Scenario
A 52-year-old patient reviews routine labs. ALT = 145 U/L. AST = 118 U/L. No prior liver disease diagnosis exists. Fatigue appears in ROS. Alcohol intake documented as 2–3 drinks on weekends. The medication list includes a statin and acetaminophen PRN.
Provider documentation (assessment)
- “Elevation of liver transaminases without established etiology. ALT 145 U/L, AST 118 U/L.”
Provider documentation (plan)
- “Repeat hepatic function panel in 4 weeks.”
- “Order hepatitis B surface antigen and hepatitis C antibody.”
- “Order RUQ ultrasound.”
- “Review acetaminophen dosing limits and supplement exposures.”
Coding
- First-listed diagnosis for that problem-focused visit: R74.01
- Add secondary codes based on documented conditions that affect care that day, such as obesity or alcohol use disorder,, only if documented and addressed.
A follow-up visit after an ultrasound showing fatty infiltration should switch away from R74.01 and use the confirmed diagnosis code that matches the imaging and provider assessment.
Reimbursement Guidelines
Multiple perspectives matter because code validity does not equal coverage approval.
R74.01 supports medical necessity for workups that match liver enzyme elevation. Clinical evaluation references describe structured approaches to abnormal liver enzymes that start with history, exam, and targeted testing.
R74.01 does not justify unrelated services. A claim with R74.01 paired to unrelated imaging or unrelated specialty referrals often triggers edits.
Major ICD-10 Coding Mistakes With Transaminitis
Multiple perspectives matter because the same mistake repeats across practices.
- Mistake 1: Using a non-specific enzyme code instead of R74.01 for ALT/AST elevation
- Mistake 2: Using R74.01 after a definitive diagnosis is documented
- Mistake 3: Missing ALT/AST values in the note
- Mistake 4: Listing R74.01 with a plan that does not address liver enzymes
- Mistake 5: Treating “transaminitis” as a diagnosis label rather than an abnormal finding
ICD-10-CM guidance explicitly supports symptom/sign reporting only until confirmation of a related definitive diagnosis.
How Long Does R74.01 Stay Appropriate?
Multiple perspectives matter because monitoring is clinical, while coding is certainty-based.
R74.01 stays appropriate across repeated visits only while the record still reflects:
- ALT/AST elevation present
- etiology not established
- workup in progress or monitoring required
Persistent elevation drives more structured evaluation pathways in clinical guidance, with NAFLD and alcohol-related liver disease listed as common causes in outpatient care.
A diagnosis established during that workup should replace R74.01 as the leading code.
Conclusion
Multiple perspectives matter because transaminitis coding sits at the intersection of clinical uncertainty and payer certainty. Elevated ALT and AST levels require documentation that states the finding, quantifies it, and explains the plan.
R74.01 is the correct ICD-10-CM code for elevation of liver transaminase levels when no definitive liver diagnosis exists.
Clean documentation protects reimbursement, supports medical necessity for workups, and reduces audit exposure. Code transitions complete the cycle once a confirmed diagnosis appears in the record.
FAQs
What is the ICD-10-CM code for transaminitis?
R74.01 matches the elevation of liver transaminase levels in ICD-10-CM.
Is R74.01 a billable code?
R74.01 is a billable ICD-10-CM diagnosis code.
Can R74.01 be first-listed?
R74.01 fits the first-listed use when elevated transaminases drive the visit, and no definitive diagnosis has been established. ICD-10-CM guidance supports symptom/sign code reporting under that condition.
What causes elevated ALT and AST?
Common causes cited in primary care literature include NAFLD and alcohol-related liver disease, with other causes such as viral hepatitis, drug-induced liver injury, and hereditary disorders.
When should R74.01 be replaced?
A confirmed diagnosis code should replace R74.01 once the provider documents a definitive etiology that has its own ICD-10-CM code.
