Synthetic data only. Never enter patient information; nothing is sent or stored. For clinicians. Not FDA cleared.For licensed clinicians. Educational demonstration on synthetic data. Never enter real patient identifiers or protected health information: everything runs in your browser and nothing is sent or stored. Clinical decision support only; not FDA cleared; physician review is required.
CPE-005 · version 1.0.0
MASLD Pattern Engine: 2023 nomenclature, FIB-4 and fibrosis risk, step by step
Steatosis must be documented before MASLD is named. Fibrosis risk follows FIB-4, then elastography or ELF.
MASLD is a diagnosis that needs imaging or biopsy evidence of steatosis plus a cardiometabolic risk factor. Metabolic labs and a raised ALT alone only justify looking: they open a fibrosis-screening prompt, never a label.
Once steatosis is documented, the question that changes management is fibrosis. The engine calculates FIB-4 with the age-adjusted cutoff, brings in liver stiffness or ELF for indeterminate or discordant results, and keeps cirrhosis surveillance, decompensation and other liver diseases in view.
Playground
Load a synthetic case or type your own values. The result recomputes as you type, and every rule links to its page.
Fibrosis risk by non-invasive tests
● Low
FIB-4 <1.3 (<2.0 from 65), stiffness <8 kPa
○ Indeterminate
Needs a second-line test
○ High
FIB-4 >2.67, stiffness ≥12 kPa or ELF ≥9.8
Liver tests and imaging
Patient
A standard US drink is about 14 g.
Cardiometabolic criteria
Other liver disease and context
Cirrhosis, decompensation and trends
What it does
- Applies the 2023 nomenclature: MASLD, MetALD and alcohol-related liver disease separated by intake.
- Calculates FIB-4 with the lower cutoff of 2.0 from age 65, and stratifies liver stiffness and ELF.
- Flags discordant non-invasive tests and the pattern of falling ALT with falling platelets.
- Withholds the MASLD label when another liver disease (viral hepatitis, a hepatotoxic drug, an iron-overload pattern) is present.
- Raises decompensation, marked-aminotransferase, impaired-function and cirrhosis-surveillance alerts.
What it never does
- Name MASLD without documented steatosis.
- Stage fibrosis from a single test.
- Trigger cancer surveillance from FIB-4 alone.
- Recommend a drug.
Safety gates
These gates run before the pattern is shown, and urgent findings are displayed first.
- Jaundice, ascites, encephalopathy or portal-hypertensive bleeding raises an urgent alert.
- ALT or AST of 1,000 U/L or more raises an urgent alert; 200 to 999 raises a priority review.
- Bilirubin above 3 mg/dL, INR above 1.5 or albumin below 3.0 g/dL raises a priority review.
- Known cirrhosis without an ultrasound in the last 6 months raises a surveillance-gap alert.
Inputs
- AST, ALT, platelets, bilirubin, INR, albumin
- Steatosis evidence, liver stiffness (kPa), ELF
- BMI or waist, glucose or HbA1c, triglycerides, HDL, blood pressure
- Alcohol intake in grams per day
- Hepatitis B and C status, drugs, ferritin and saturation, cirrhosis and decompensation signs
Scope
In scope
- Adults aged 18 and over
Routed out
- Patients under 18
The full rule catalog
21 active rules and 1 sandbox or context entries. Each has its own page with conditions, outputs and evidence. 22 of 22 active rules are exercised by at least one synthetic case.
Scope and validity
Classification
Fibrosis risk
Safety
Context triggers
Missing data
Calculations
Synthetic cases
Every case is synthetic. Open one to see the inputs, the full result and the rule trace; then change the values.
LIVER-FX-01
Steatosis with metabolic risk and a low FIB-4
A 52-year-old man with fatty liver on ultrasound, BMI 31 and triglycerides 190.
LIVER-FX-02
Type 2 diabetes, no imaging yet
A 58-year-old with diabetes and normal enzymes: the screening question.
LIVER-FX-03
Indeterminate FIB-4
FIB-4 of 2.0 in a 56-year-old with steatosis.
LIVER-FX-04
High FIB-4
FIB-4 above 5 in a 63-year-old man with low platelets.
LIVER-FX-05
FIB-4 of 1.65 at age 70
Low risk under the age-adjusted cutoff of 2.0.
LIVER-FX-06
Stiffness 14 kPa with a low FIB-4
Discordant tests: the elastography result prevails as a warning.
LIVER-FX-07
ELF 10.1
A high ELF with FIB-4 in the indeterminate range.
LIVER-FX-08
Alcohol in the MetALD range
A woman drinking about 35 g a day with steatosis and metabolic risk.
LIVER-FX-09
Alcohol-related liver disease predominant
About 90 g a day in a man with steatosis.
LIVER-FX-10
Hepatitis B surface antigen positive
Steatosis plus a second liver disease.
LIVER-FX-11
Amiodarone exposure
A hepatotoxic drug is on the medication list.
LIVER-FX-12
ALT falling while platelets fall
Known fatty liver, ALT now normal and platelets down to 140.
LIVER-FX-13
Cirrhosis with no ultrasound for nine months
A surveillance gap in known cirrhosis.
LIVER-FX-14
Cirrhosis with recent surveillance
Ultrasound four months ago.
LIVER-FX-15
Jaundice and ascites
Signs of decompensation.
LIVER-FX-16
ALT 1,350 U/L
Values far above anything MASLD explains.
LIVER-FX-17
ALT 260 U/L
Marked but not extreme elevation.
LIVER-FX-18
Bilirubin 4.2 and INR 1.7
Impaired liver function.
LIVER-FX-19
Transferrin saturation 62% with ferritin 780
An iron-overload pattern in a man with steatosis.
LIVER-FX-20
Raised ALT and no viral testing
ALT 78 with no hepatitis B or C results.
LIVER-FX-21
A teenager is outside the adult pathway
Fourteen years old.
LIVER-FX-22
No steatosis and no screening trigger
A healthy 32-year-old.
LIVER-FX-23
Steatosis but no platelet count
FIB-4 cannot be calculated.
LIVER-FX-24
Asian patient with BMI 24
The Asian BMI criterion (23) is met.
LIVER-FX-25
Steatosis in a lean patient with no metabolic risk
Fatty liver but no cardiometabolic criterion.
Evidence
Guidelines and references the rules cite. Each rule page lists the ones that support it.
EV-AASLD-2023Rinella ME, Neuschwander-Tetri BA, Siddiqui MS, et al. AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease. Hepatology. 2023;77(5):1797-1835.
Supports: FIB-4 first for risk stratification; thresholds <1.3 and >2.67; elastography 8 and 12 kPa; ELF 7.7 and 9.8 ALT upper limits near 29–33 U/L (men) and 19–25 U/L (women) Cardiovascular risk is the leading cause of death in MASLD
EV-DELPHI-2023Rinella ME, Lazarus JV, Ratziu V, et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology. 2023;78(6):1966-1986.
Supports: MASLD criteria: steatosis plus at least one cardiometabolic risk factor and no other cause MetALD and alcohol-related liver disease separated by intake
EV-MCPHERSON-2017McPherson S, Hardy T, Dufour JF, et al. Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis. Am J Gastroenterol. 2017;112(5):740-751.
Supports: FIB-4 lower cutoff of 2.0 in patients aged 65 and over
EV-EASL-NIT-2021European Association for the Study of the Liver. EASL Clinical Practice Guidelines on non-invasive tests for evaluation of liver disease severity and prognosis, 2021 update. J Hepatol. 2021;75(3):659-689.
Supports: Use of elastography and serum tests in sequence, and handling of discordant results
EV-AASLD-HCC-2023Singal AG, Llovet JM, Yarchoan M, et al. AASLD Practice Guidance on prevention, diagnosis, and treatment of hepatocellular carcinoma. Hepatology. 2023;78(6):1922-1965.
Supports: Surveillance with ultrasound with or without AFP every 6 months in cirrhosis
EV-CDC-HEP-2020Schillie S, Wester C, Osborne M, et al. CDC Recommendations for Hepatitis C Screening Among Adults. MMWR Recomm Rep. 2020;69(2):1-17; and Conners EE, et al. Screening and Testing for Hepatitis B Virus Infection: CDC Recommendations. MMWR Recomm Rep. 2023;72(1):1-25.
Supports: One-time universal screening for hepatitis C and hepatitis B in adults
EV-EASL-HFE-2022European Association for the Study of the Liver. EASL Clinical Practice Guidelines on haemochromatosis. J Hepatol. 2022;77(2):479-502.
Supports: Transferrin saturation >45% with raised ferritin prompts HFE testing
Frequently asked questions
Can the engine call MASLD from labs alone?
No. MASLD needs hepatic steatosis documented by imaging or biopsy plus at least one cardiometabolic risk factor. With risk factors but no steatosis the engine opens a FIB-4 screening prompt, in line with AASLD 2023, and says plainly that it is not a diagnosis.
Which FIB-4 cutoffs does it use?
Below 1.3 is low risk, 1.3 to 2.67 indeterminate, above 2.67 high risk. From age 65 the lower cutoff is 2.0, because FIB-4 rises with age and the standard cutoff over-calls risk in older patients.
What happens when FIB-4 and elastography disagree?
The engine says so and does not reassure. FIB-4 low with stiffness at 12 kPa or above, or FIB-4 high with stiffness below 8 kPa, is flagged as discordant and prompts a repeat or a different test.
Does a high FIB-4 trigger hepatocellular carcinoma surveillance?
No. AASLD 2023 recommends surveillance in cirrhosis. A high FIB-4 raises the question of advanced fibrosis and a hepatology referral; surveillance is flagged only when cirrhosis is documented and no ultrasound has been done in six months.
Why does falling ALT with falling platelets get a warning?
In steatotic liver disease, ALT can fall as the liver scars. Together with falling platelets that pattern can mean advancing fibrosis rather than improvement, so the engine asks for FIB-4 to be recalculated.
Specification status: Executable specification v1.0.0, authored by Biod from the narrative CPE-005 specification and current guidance. Reviewed by Dr. Vinicius Amaral, D.O. Not for clinical production use.
Clinical review: Dr. Vinicius Amaral, D.O., Medical reviewer, 2026-10-03.
Keep going
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CPE-007
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CPE-004
Iron Deficiency Pattern Engine
Iron status from ferritin and transferrin saturation, read correctly when inflammation, heart failure or kidney disease changes the rules.
Resources
Chronic low-grade inflammation and biomarker patterns
Game
Pattern challenge
Guess what the engine will report.
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