Fatty Liver ICD-10 Codes: UK Guide

Fatty liver ICD-10 coding is essential for accurate clinical documentation, NHS commissioning and national audit across England. Fatty liver disease, now classified within the steatotic liver disease (SLD) framework, ranges from simple hepatic steatosis to metabolic dysfunction-associated steatohepatitis (MASH) and cirrhosis. Whether the cause is metabolic, alcohol-related or mixed, selecting the correct WHO ICD-10 code ensures patients are appropriately tracked and managed. This article explains the relevant ICD-10 codes used in UK practice, how fatty liver disease is classified and diagnosed, and what treatment options are currently available on the NHS.

What is fatty liver disease and how is it classified?

Fatty liver disease is classified under the steatotic liver disease framework into MASLD (metabolic), alcohol-related liver disease, and a mixed category (MetALD), with severity ranging from simple steatosis to cirrhosis.

Fatty liver disease is a condition in which excess fat accumulates within liver cells, and it is broadly divided into categories depending on whether alcohol is the primary cause. The main categories within the current steatotic liver disease (SLD) framework are metabolic dysfunction-associated steatotic liver disease (MASLD, formerly called non-alcoholic fatty liver disease or NAFLD), alcohol-related liver disease (ArLD), and a mixed category termed metabolic dysfunction-associated alcohol-related liver disease (MetALD), which applies when both metabolic risk factors and significant alcohol intake contribute. This distinction matters clinically because the underlying drivers, investigations and management pathways differ considerably between groups.

MASLD encompasses a spectrum of severity. At the milder end sits simple hepatic steatosis, where fat is present but inflammation and cell damage are minimal. A more serious form, metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH), involves active inflammation and hepatocyte injury, which can progress over years to fibrosis, cirrhosis and, in some cases, hepatocellular carcinoma.^[2][13] Risk factors for MASLD include:

• Obesity or overweight, particularly central adiposity

• Type 2 diabetes and insulin resistance

• Dyslipidaemia (raised triglycerides or low HDL cholesterol)

• Hypertension

Alcohol-related fatty liver results from the hepatotoxic effects of ethanol metabolism. Even in the absence of cirrhosis, chronic excess alcohol intake causes steatosis that can progress to alcoholic hepatitis and fibrosis. Importantly, both metabolic and alcohol-related factors can coexist in the same patient, and clinicians must assess alcohol intake carefully before assigning a diagnostic category.

Secondary causes of hepatic steatosis or steatohepatitis should also be considered and excluded as part of baseline assessment. These include viral hepatitis, certain medications (such as corticosteroids, amiodarone and tamoxifen), Wilson's disease, autoimmune hepatitis and haemochromatosis, among others. This exclusion step is standard practice in UK clinical pathways.

The terminology in this field has evolved rapidly since 2023, and some clinical documents still use the older NAFLD and NASH labels, so familiarity with both sets of terms is helpful when reading referral letters or discharge summaries.

Which ICD-10 codes are used for fatty liver in the UK?

UK NHS practice uses WHO ICD-10 codes K76.0 for non-alcoholic or metabolic fatty liver and K70.0 for alcoholic fatty liver; US ICD-10-CM codes do not apply in this context.

In the UK, fatty liver disease is coded using the World Health Organization's International Classification of Diseases, Tenth Revision (WHO ICD-10), and the relevant codes sit within the K70 to K77 block covering diseases of the liver. It is important to note that NHS services use WHO ICD-10, not the US adaptation ICD-10-CM, which contains specific NASH codes that do not apply in the UK context.^[1] The most commonly applied WHO ICD-10 codes for fatty liver are:

• K70.0 Alcoholic fatty liver

• K76.0 Fatty (change of) liver, not elsewhere classified (used for non-alcoholic or metabolic steatosis)

• K75.8 Other specified inflammatory liver diseases (sometimes applied when steatohepatitis with active inflammation is documented, though UK coding practice for NASH/MASH under this code varies and coders should refer to the current NHS England National Clinical Coding Standards for ICD-10 for definitive guidance)

• K74.0 Hepatic fibrosis and K74.6 Other and unspecified cirrhosis of liver (applied when disease has progressed)

NHS coding teams and clinical coders working within NHS trusts apply these codes to inpatient episodes. Outpatient diagnosis coding in Hospital Episode Statistics (HES) data held by NHS England is less consistently applied than inpatient coding, and the completeness of outpatient diagnostic data varies across trusts.^[15] Accurate coding is important not only for individual patient records but also for commissioning decisions made by Integrated Care Boards (ICBs) and for national audit purposes.

ICD-10 predates the 2023 nomenclature shift from NAFLD to MASLD. The transition to ICD-11, which introduces more granular metabolic liver disease codes, is underway internationally, but NHS systems in England continue to use ICD-10 as the primary coding framework for most clinical settings at the time of writing. Clinicians and coders should document the underlying aetiology and stage of disease as precisely as possible in clinical notes, as this supports accurate code selection and avoids the catch-all K76.0 being applied when a more specific code is appropriate.

How do doctors diagnose and stage fatty liver disease?

Diagnosis follows NICE NG49, using FIB-4 index as a first-line fibrosis tool in primary care, with the ELF test as second-line and transient elastography or biopsy in secondary care.

Fatty liver disease is most commonly identified incidentally on abdominal ultrasound or through abnormal liver blood tests, and NICE guidance (NG49) outlines a structured pathway for investigation and risk stratification. Initial assessment typically includes liver function tests (LFTs), a fasting lipid profile, HbA1c or fasting glucose, and a full alcohol history. A raised alanine aminotransferase (ALT) is a common but non-specific finding, and normal LFTs do not exclude significant steatosis or fibrosis.

Non-invasive fibrosis assessment is central to staging. In line with NICE NG49, the FIB-4 index (calculated from age, ALT, AST and platelet count) or the NAFLD Fibrosis Score (NFS) are recommended as first-line tools in primary care to identify patients at higher risk of advanced fibrosis.^[2][3] A low FIB-4 score (generally below 1.30 in those under 65, with a different threshold applying in those aged 65 and over) suggests low fibrosis risk and supports continued monitoring in primary care. Patients with indeterminate or high FIB-4 or NFS results are offered the Enhanced Liver Fibrosis (ELF) test as a second-line assessment, with referral to secondary care guided by the result.^[2][3] Clinicians should refer to NICE NG49 for the current age-specific thresholds and referral criteria, as these are subject to update.

In secondary care, transient elastography (FibroScan) provides a non-invasive measure of liver stiffness and steatosis. Liver biopsy remains the reference standard for confirming MASH and grading inflammation and fibrosis, but it carries procedural risks and is reserved for cases where non-invasive tests are inconclusive or where the diagnosis will directly change management. MRI-based techniques, including MR elastography and MRI-PDFF (proton density fat fraction), are increasingly used in specialist centres.

Patients with suspected cirrhosis require additional assessment including upper gastrointestinal endoscopy to screen for varices, and six-monthly liver ultrasound for hepatocellular carcinoma surveillance. The use of alpha-fetoprotein (AFP) alongside ultrasound in surveillance programmes may vary according to local protocol and BSG guidance; patients should follow the plan agreed with their hepatology team.

What treatment options are available on the NHS?

No drug is currently licensed specifically for MASLD or MASH in the UK; NHS treatment centres on lifestyle modification, weight loss, and management of underlying metabolic conditions.

At the time of writing, no pharmacological treatment is licensed specifically for MASLD or MASH in the UK. Clinicians should check current MHRA and NICE guidance, as the licensing landscape in this area is evolving. NHS management therefore centres on lifestyle modification, cardiovascular risk reduction and treatment of underlying metabolic conditions. Weight loss remains the most evidence-based intervention: a sustained reduction of 7 to 10 percent of body weight is associated with meaningful improvements in hepatic steatosis and, in some cases, regression of fibrosis.^[2][14] Structured dietary programmes and physical activity support are recommended as first-line measures.

For patients with type 2 diabetes and coexisting fatty liver disease, NICE-recommended glucose-lowering agents may offer additional hepatic benefit. GLP-1 receptor agonists such as semaglutide and the dual GIP and GLP-1 receptor agonist tirzepatide (Mounjaro), which is MHRA-authorised both for type 2 diabetes and for chronic weight management, have shown reductions in hepatic fat in clinical studies.^[6][7] SGLT-2 inhibitors are another class with emerging hepatic data. In all cases, use of these medicines is guided by their licensed indications rather than a specific liver disease indication, and prescribing decisions should follow NICE guidance and individual clinical assessment. Bolt Pharmacy is a GPhC-registered UK online pharmacy offering online weight-management consultations with prescriber review and pharmacist support; clinically appropriate options may be considered following assessment, where a prescriber determines this is suitable for an individual patient.

Alcohol-related fatty liver is managed primarily through supported alcohol reduction or abstinence, with referral to specialist alcohol services where appropriate. Cardiovascular risk management, including statin therapy where indicated, is important across both MASLD and ArLD populations given the high burden of cardiovascular comorbidity.

Patients with advanced fibrosis or cirrhosis are managed within hepatology services, and those with end-stage liver disease may be assessed for liver transplantation. Referral to hepatology should be considered when non-invasive tests indicate advanced fibrosis, when the diagnosis is uncertain, or when there are features of decompensation.

Patients and carers should seek same-day emergency care (by calling 999 or attending an emergency department) if they experience vomiting blood, passing black or tarry stools, sudden confusion or difficulty staying awake, or severe abdominal pain with fever, as these may indicate serious complications requiring urgent assessment. New or worsening jaundice, abdominal swelling or unexplained weight loss should prompt prompt contact with a GP for reassessment.

Scientific References

1. K70-K77: Diseases of liver — NHS ICD-10 5th Edition Class Browser.
2. Metabolic dysfunction-associated steatotic liver disease (NG49).
3. Non-alcoholic fatty liver disease (NAFLD) — short version of draft guideline (NG49).
4. NG49 Recommendations for research — non-invasive tests for MASLD and advanced liver fibrosis.
5. GID-TA11477 Draft scope post-referral — no medicines approved for MASLD or MASH in the UK.
6. MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss.
7. Tirzepatide | Drugs | BNF — NICE.
8. Tirzepatide: a medicine to manage type 2 diabetes and obesity.
9. Rezdiffra (resmetirom) — European Medicines Agency EPAR.
10. Newsome PN et al. A Placebo-Controlled Trial of Subcutaneous Semaglutide in Nonalcoholic Steatohepatitis. N Engl J Med..
11. Metabolic dysfunction and alcohol-related liver disease (MetALD): Position statement by an expert panel on alcohol-related liver disease.
12. Evolution of the nomenclature of steatotic liver diseases: Towards a paradigm shift.
13. Systematic Mapping of Worldwide Research on MASLD and MASH.
14. Histological efficacy of anti-diabetic agents in MASH and the mediating role of weight loss: A network meta-analysis.
15. Provisional Monthly Hospital Episode Statistics for Admitted Patient Care, Outpatient and Accident and Emergency Data.

Frequently Asked Questions