Accuracy of non-invasive tests for diagnosing liver fibrosis and steatosis: A systematic review

Abstract

BACKGROUND

Liver fibrosis is a key determinant of prognosis and management in chronic liver diseases. Although liver biopsy is considered the gold standard for fibrosis assessment, its invasiveness, sampling variability, and associated risks have prompted increasing reliance on non-invasive tests. This systematic review evaluates the diagnostic accuracy and clinical applicability of non-invasive modalities for diagnosing liver fibrosis in adult patients with chronic liver diseases.

AIM

To systematically evaluate the diagnostic accuracy, clinical utility, and applicability of non-invasive tests for detecting and staging liver fibrosis in adult patients with chronic liver diseases, using liver biopsy as the reference standard.

METHODS

A systematic literature search was conducted using predefined search terms combining liver fibrosis, chronic liver disease, non-invasive diagnostic tests, and diagnostic accuracy measures, with liver biopsy as the reference standard. Studies were selected based on a PICO (Population, Intervention, Comparison, Outcome) framework including adults (≥ 18 years) with chronic liver diseases such as hepatitis B, hepatitis C, non-alcoholic fatty liver disease, and alcohol-related liver disease. Eligible interventions included serum biomarkers (e.g., aspartate aminotransferase-to-platelet ratio index, fibrosis-4 index, enhanced liver fibrosis), imaging-based techniques (e.g., transient elastography, acoustic radiation force impulse, magnetic resonance imaging elastography), and combined diagnostic algorithms. Diagnostic accuracy outcomes including sensitivity, specificity, positive predictive value, and negative predictive value were extracted. Two independent reviewers performed abstract and full-text screening according to predefined inclusion and exclusion criteria, with disagreements resolved by consensus or a third reviewer.

RESULTS

The included studies comprised prospective and retrospective cohort studies, randomized controlled trials, and cross-sectional studies. Elastography-based techniques consistently demonstrated high diagnostic accuracy for detecting significant and advanced fibrosis across multiple chronic liver disease etiologies. Serum biomarker panels showed variable performance but were effective as first-line screening tools due to their accessibility and cost-effectiveness. Heterogeneity was observed in study design, fibrosis staging systems, and cut-off values.

CONCLUSION

Non-invasive tests represent reliable and clinically applicable alternatives to liver biopsy for fibrosis assessment in chronic liver diseases. Elastography-based modalities, particularly transient elastography and two-dimensional shear wave elastography, demonstrated consistently high diagnostic accuracy for advanced fibrosis across included studies. Serum biomarker panels such as fibrosis-4 index and enhanced liver fibrosis showed variable performance but are effective as first-line screening tools due to their accessibility and cost-effectiveness. A sequential diagnostic approach integrating serum biomarkers followed by imaging modalities improves overall diagnostic accuracy and reduces the need for invasive procedures. However, significant heterogeneity in study design, patient populations, and cut-off values limits standardization and highlights the need for larger multicentric validation studies.

Key Words: Liver fibrosis; Non-invasive test; Chronic liver diseases; Liver biopsy; Gold standard

Core Tip: Non-invasive tests are increasingly replacing liver biopsy for fibrosis assessment in chronic liver diseases due to their safety and accessibility. This systematic review highlights that elastography-based modalities provide high diagnostic accuracy for detecting significant fibrosis, while serum biomarkers serve as effective first-line screening tools. Despite variability in cut-off values and study designs, a stepwise approach combining serum and imaging-based non-invasive tests improves diagnostic reliability. Integrating these modalities into clinical practice can reduce the need for invasive procedures while maintaining accurate fibrosis staging and guiding patient management.

INTRODUCTION

Liver cirrhosis is a chronic, progressive liver disease characterized by fibrosis and the formation of regenerative nodules that distort the normal hepatic lobular architecture. It represents the end stage of various chronic liver injuries and is a major global health concern. According to the Global Burden of Disease study, cirrhosis accounts for more than one million deaths annually and ranks among the top 15 causes of mortality worldwide. The disease burden is particularly high in low-income and middle-income countries, including India, where viral hepatitis, alcohol consumption, and metabolic syndrome contribute substantially to its rising incidence. The etiologies of cirrhosis are diverse. Chronic hepatitis B virus and hepatitis C virus infections remain the leading causes globally, although their prevalence has been reduced in some regions through vaccination and antiviral therapy[1,2]. Excessive alcohol intake is another major driver, responsible for nearly half of cirrhosis deaths in Western countries[3].

Non-alcoholic fatty liver disease (NAFLD), linked to obesity and type 2 diabetes, has emerged as a rapidly increasing cause of chronic liver disease and cirrhosis worldwide[4]. Other etiologies include autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, Wilson’s disease, and hemochromatosis. Regardless of etiology, the pathophysiological hallmark is chronic hepatocellular injury, activation of hepatic stellate cells, deposition of extracellular matrix, and progressive fibrosis that eventually culminates in cirrhosis[5].

Liver biopsy has been considered the gold standard for diagnosis and staging of liver fibrosis. A liver biopsy involves inserting a needle into the liver to obtain a small piece of tissue, which is then examined under a microscope. Histological features assessed include fibrous septa, loss of lobular architecture, regenerative nodules, and inflammatory infiltrates. Despite its diagnostic value, liver biopsy is invasive, painful, and associated with potential complications such as bleeding, bile leak, and injury to adjacent organs, with complication rates reported between 0.5%-1% and mortality less than 0.1%[4,5]. Furthermore, biopsy suffers from sampling variability and inter-observer differences, which can affect diagnostic accuracy[6,7].

To overcome these limitations, non-invasive diagnostic alternatives have been developed. Transient elastography (FibroScan) is one such method, which measures liver stiffness by assessing the velocity of shear waves propagated through hepatic tissue. It is painless, quick, and reproducible, with high diagnostic accuracy for advanced fibrosis and cirrhosis. However, it has reduced reliability in obese patients, those with ascites, and in cases of acute inflammation[8]. Serum biomarkers, such as the aspartate aminotransferase to platelet ratio index (APRI) and fibrosis-4 index (FIB-4), are inexpensive and widely available. These indices rely on routine laboratory parameters but their diagnostic performance can be influenced by comorbid conditions like thrombocytopenia or hemolysis. More advanced imaging-based techniques, including magnetic resonance elastography and acoustic radiation force impulse (ARFI) imaging, have shown excellent results but are limited by high cost and availability[9].

The present study aims to evaluate the diagnostic accuracy and clinical applicability of non-invasive tests including transient elastography, APRI, liver viscosity and FIB-4 in patients with chronic liver disease, and to compare their performance against liver biopsy. By identifying the strengths and limitations of each method, this research seeks to contribute to the optimization of diagnostic pathways, improve patient compliance, and reduce reliance on invasive liver biopsy.

MATERIALS AND METHODS

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Search strategy

A comprehensive literature search was performed using the PubMed database. The following search strategy, combining keywords and Boolean operators, was applied: (“liver fibrosis” OR “chronic liver disease” OR “hepatic fibrosis”) AND (“non-invasive tests” OR “serum biomarkers” OR “liver elastography” OR “transient elastography” OR “MRI elastography”) AND (“diagnostic accuracy” OR “sensitivity” OR “specificity” OR “PPV” OR “NPV”) AND (“liver biopsy” OR “gold standard”). The search was limited to studies published within the last five years.

PICO framework

Population (P): Adults (≥ 18 years) diagnosed with compensated chronic liver disease, including hepatitis B, hepatitis C, NAFLD, and alcohol-related liver disease.

Intervention (I): Non-invasive tests for liver fibrosis diagnosis, including serum biomarkers [e.g., FIB-4, APRI, enhanced liver fibrosis (ELF)] and imaging modalities (e.g., transient elastography and other elastography) based techniques such as ARFI, vibration-controlled transient elastography (VCTE), virtual touch quantification (VTQ) and viscosity plane-wave ultrasound (Vi PLUS) and magnetic resonance elastography.

Comparator (C): Liver biopsy, considered the gold standard for fibrosis assessment. In one study, VCTE, was used as an alternative reference standard.

Outcome (O): Diagnostic accuracy measures, including sensitivity, specificity, positive predictive value, and negative predictive value, along with clinical applicability such as cost-effectiveness and feasibility.

Inclusion criteria

Studies meeting the following criteria were included: (1) Diagnostic accuracy studies, including prospective and retrospective cohort studies, randomized controlled trials, and cross-sectional studies; (2) Studies involving adult participants (≥ 18 years) with chronic liver disease; (3) Studies evaluating non-invasive diagnostic tests for liver fibrosis using liver biopsy as the reference standard; (4) Studies reporting diagnostic accuracy outcomes (sensitivity, specificity, positive predictive value, negative predictive value) and addressing clinical applicability; and (5) Studies published within the last five years.

Exclusion criteria

Studies were excluded if they: (1) Focused exclusively on acute liver disease or included patients with decompensated chronic liver disease; (2) Included pediatric populations; (3) Were review articles, case reports, editorials, or lacked full diagnostic data; (4) Did not use liver biopsy or an equivalent gold standard comparator (vibration controlled transient elastography); and (5) Did not report diagnostic accuracy metrics (e.g., sensitivity or specificity).

Study selection

A total of 147 studies were initially identified. After removing 10 duplicates, 137 studies underwent primary screening based on titles and abstracts.

Primary screening: 20 studies were included, and 117 were excluded.

Secondary (full-text) screening: 9 studies were included, while 11 were excluded for the following reasons: Wrong comparator (n = 7), wrong outcome (n = 2), wrong intervention (n = 1), wrong study design (n = 1).

Data extraction

Data extraction was performed independently by two reviewers using predefined data extraction sheets. Discrepancies were resolved through discussion and consensus.

RESULTS

Study selection and characteristics

A total of eight studies met the inclusion criteria, evaluating non-invasive diagnostic modalities for liver fibrosis and steatosis, with liver biopsy serving as the reference standard (and VCTE in one study). The studies were predominantly single-center cohort designs and included patients with NAFLD/metabolic dysfunction-associated steatotic liver disease (MASLD), mixed chronic liver disease, and chronic hepatitis B with coexisting MASLD. Fibrosis staging was most commonly performed using the METAVIR or non-alcoholic steatohepatitis clinical research network scoring systems. The terminology varied across studies, with the use of NAFLD, MASLD, and metabolic dysfunction-associated steatohepatitis (MASH), reflecting the evolving nomenclature in this field.

Elastography-based tests

Transient elastography measures liver stiffness and can be performed bedside with good reproducibility. Two-dimensional (2D)-shear wave elastography (SWE) is a new SWE in two dimensions such as point SWE and real-time SWE. ARFI, an imaging technique which is available on ultrasound machines produces short- wave duration acoustic pulses that generate shear waves, providing quantitative tissue stiffness measurements (measured in m/second). ARFI values increase with the severity of fibrosis. The general cut-off values suggested are < 1.3 m/second for mild/no fibrosis, 1.3-1.7 m/second for significant fibrosis and > 1.7-2.1 m/second for advanced fibrosis/cirrhosis.

Transient elastography, 2D-SWE, ARFI-based techniques, and VCTE demonstrated good to excellent diagnostic performance for advanced fibrosis and cirrhosis across studies. VCTE is a non-invasive, bedside diagnostic tool that measures liver stiffness (fibrosis) and steatosis (fat).

In mixed chronic liver disease, transient elastography and ElastPQ (ElastPQ is an ARFI-based point SWE technique) achieved area under the receiver operating characteristics (AUROCs) ranging from 0.81 to 0.93 for ≥ F3-F4 fibrosis, with sensitivities of approximately 76%-93% and specificities of 71%-91% at cut-offs between 8.3 kPa and 16.5 kPa. VTQ ARFI demonstrated comparable sensitivity but slightly lower specificity. VTQ measures the velocity of shear wave generated by a short-duration acoustic force impulse, with values expressed in units of velocity (m/second).

In chronic liver disease cohorts, 2D-SWE showed AUROCs of 0.85-0.87 for significant and severe fibrosis (≥ F2-F3), with sensitivities of approximately 76% and specificities of 86%-88%, and an AUROC of 0.96 for cirrhosis. Transient elastography demonstrated similar performance across these stages, with AUROCs ranging from 0.87 to 0.96.

In MASLD populations, both 2D-SWE and TE showed strong diagnostic accuracy for advanced fibrosis, with AUROCs of approximately 0.90-0.93 at cut-offs of 7.2-8.4 kPa. Vi PLUS achieved an AUROC of 0.81 kPa at 2.1 kPa, with very high sensitivity (100%) but modest specificity (58%). Vi PLUS is a new imaging technique that investigates the dispersion properties of shear waves that can serve as an indirect way to measure liver viscosity. Another MASLD/MASH study reported excellent diagnostic performance for S-Shearwave (AUROC = 0.94), TE (AUROC = 0.98), and 2D-SWE (AUROC = 0.91) for ≥ F3 fibrosis, with transient elastography demonstrating both high sensitivity (95.6%) and specificity (94.2%) at a cut-off of 8.9 kPa. Simpler non-invasive scores such as FIB-4 and NAFLD fibrosis score (NFS) also showed acceptable performance in this cohort.

In patients with chronic hepatitis B and coexisting MASLD, VCTE liver stiffness measurement detected cirrhosis with an AUROC of 0.86 at a cut-off of 11.25 kPa (sensitivity 79%, specificity 90%), while controlled attenuation parameter quantified severe steatosis with an AUROC of 0.84 at 313 dB/m (sensitivity 86%, specificity 82%). Detailed elastography estimates are presented in Table 1.

Table 1 Elastography assessment results.

Ref.	Population	Test	Cut-off	Target	Sensitivity (%)	Specificity (%)	AUROC	PPV (%)	NPV (%)
Elastography studies
Atzori et al[12]	Mixed CLD (n = 150)	TE	9.7 kPa	≥ F3	79	75	0.841
		TE	16.5 kPa	F4	93	91	0.939
		ElastPQ	8.32 kPa	≥ F3	76	71	0.812
		ElastPQ	10.41 kPa	F4	83	73	0.856
		VTQ ARFI	10.88 kPa	≥ F3	76	72	0.782
		VTQ ARFI	12.47 kPa	F4	69	78	0.826
Kovatsch et al[13]	CLD	2D-SWE		≥ F2	76.4	86	0.852
		2D-SWE		≥ F3	75.6	88.1	0.868
		2D-SWE		F4			0.956
		TE		≥ F2			0.875
		TE		≥ F3			0.868
		TE		F4			0.956
Liguori et al[11]	MASLD	2D-SWE	7.2 kPa	≥ F3			0.9
		TE	8.4 kPa	≥ F3			0.93
		Vi PLUS	2.1 kPa	Fibrosis	100	58.1	0.81
Liguori et al[12]	MASLD/MASH	S-Shearwave	8.1 kPa	≥ F3	95.6	78.8	0.942
		TE	8.9 kPa	≥ F3	95.6	94.2	0.979
		2D-SWE	7.6 kPa	≥ F3	82.6	84.6	0.906
		FIB-4		≥ F3			0.768
		NFS		≥ F3			0.833
Liu et al[14]	CHB + MASLD (n = 368)	VCTE (LSM)	11.25 kPa	Cirrhosis	79	90	0.86	89	81
		CAP	313 dB/m	Severe steatosis	86	82	0.84	82	85
Serum biomarker studies
Kang et al[20]	MASLD (n = 153)	ELF	9.6	F3-F4	67.9	84	0.829	48.7	89.2
		FIB-4 to ELF	ELF 9.8	F3-F4	67.9	90.4	0.791	75.2	86.8
Younossi et al[21]	NAFLD (n = 829)	ELF		Advanced fibrosis			0.811
		ELF + FIB-4 (low)	ELF ≥ 7.2, FIB-4 ≥ 0.74	Rule out	92.5				95.1
		ELF + FIB-4 (high)	ELF ≥ 9.8, FIB-4 ≥ 2.9	Rule in		99.7		95
Modeling study
Tapper et al[28]	NAFLD (model)	FIB-4		≥ F3	69-772	70
		ELF	9.37	≥ F3	73	80
		VCTE	9.1 kPa	≥ F3	77	78

¹Area under the receiver operating characteristic reported for the detection of advanced fibrosis; sensitivity and specificity were not provided separately in the original study.

²Sensitivity is presented as a range because different diagnostic thresholds or scenarios were evaluated in the modeling study.

CLD: Chronic liver disease; MASLD: Metabolic dysfunction-associated steatotic liver disease; MASH: Metabolic dysfunction-associated steatohepatitis; CHB: Chronic Hepatitis B; NAFLD: Non-alcoholic fatty liver disease; NFS: NAFLD fibrosis score; TE: Transient elastography; VTQ: Virtual touch quantification; ARFI: Acoustic radiation force impulse; 2D: Two-dimensional; SWE: Shear wave elastography; Vi PLUS: Viscosity plane-wave ultrasound; VCTE: Vibration-controlled transient elastography; LSM: Liver stiffness measurement; CAP: Controlled attenuation parameter; ELF: Enhanced liver fibrosis; FIB-4: Fibrosis-4 index; AUROC: Area under the receiver operating characteristic; PPV: Positive predictive value; NPV: Negative predictive value.

Serum-based tests and multistep algorithms

Serum ELF testing demonstrated consistently good accuracy for detecting advanced fibrosis in biopsy-confirmed NAFLD/MASLD. ELF represents a notable marker derived from three serum biomarkers: Hyaluronic acid, procollagen III N-terminal peptide and tissue inhibitor of matrix metalloproteinase 1. FIB-4 is a non-invasive tool to calculate liver scarring and is calculated using age, aspartate aminotransferase, alanine aminotransferase and platelets.

In MASLD cohorts, an ELF cut-off around 9.6 yielded an AUROC of approximately 0.83, with sensitivity of about 68% and specificity of approximately 84%, providing a high negative predictive value (approximately 89%) for ruling out advanced fibrosis (F3-F4). Larger NAFLD datasets showed similar performance, with AUROCs of 0.81 compared with biopsy and 0.79 compared with elastography, and higher ELF values observed in patients with advanced fibrosis.

Sequential testing strategies improved diagnostic accuracy compared with individual tests. In MASLD, applying an ELF cut-off of 9.8 within the indeterminate FIB-4 range (1.30-2.67) maintained sensitivity (approximately 68%) while increasing specificity to approximately 90%, thereby reducing the need for further evaluation in a substantial proportion of patients.

In a larger NAFLD cohort, combined low cut-offs (ELF ≥ 7.2 and FIB-4 ≥ 0.74) achieved high sensitivity (92.5%) and negative predictive value (95.1%) for ruling out advanced fibrosis. Conversely, higher cut-offs (ELF ≥ 9.8 and FIB-4 ≥ 2.9) demonstrated near-perfect specificity (99.7%) and high positive predictive value (95.0%) for ruling in advanced fibrosis.

Modeling evidence

In a cost-effectiveness model of NAFLD, biopsy-calibrated diagnostic performance for advanced fibrosis showed FIB-4 sensitivity ranging from 0.69 to 0.77 with specificity of 0.70. ELF (cut-off 9.37) demonstrated sensitivity of 0.73 and specificity of 0.80, while VCTE (cut-off 9.1 kPa) showed sensitivity of 0.77 and specificity of 0.78. Within this framework, ELF and VCTE were modestly more specific than FIB-4, supporting their role as second-line tests in multistep diagnostic pathways.

DISCUSSION

This systematic review evaluated the diagnostic accuracy of noninvasive biomarkers for the assessment of liver fibrosis in patients with chronic liver diseases. The principal finding is that no single noninvasive test is sufficient for reliable fibrosis staging across the full spectrum of disease severity; rather, the available evidence supports a sequential, multistep diagnostic approach that combines the complementary strengths of serum markers and elastography. Across the included studies, transient elastography (transient elastography, Fibroscan) consistently demonstrated the highest accuracy for fibrosis detection across different patient populations, including those with coexisting CHB and MASLD, with AUROCs ranging from 0.86 to 0.98[9-14]. However, its use is limited in obese patients and those with ascites with failure rates ranging between 2.4% and 9.4%[15-19]. A key finding is the significant inter-device variability across elastography methods, with clinical and statistical implications. A direct comparison of three shear wave elastography technologies revealed that transient elastography and ElastPQ were statistically equivalent, while VTQ ARFI showed significantly lower accuracy and was additionally confounded by hepatic steatosis and lobular inflammation, an effect particularly problematic in MASLD where steatosis is definitionally present. An advantage that ARFI has over transient elastography is that it can be used in patients with ascites.

The ELF test emerged as the best performing standalone serum biomarker, outperforming both FIB-4 and NFS[20,21]. A meaningful clinical advantage of the ELF test is its ability to maintain diagnostic performance in elderly patients and those with type 2 diabetes, populations in whom FIB4 tends to overclassify due to age related changes in aspartate aminotransferase and platelet count[22]. However, ELF is a proprietary assay with associated costs and limited global availability, and its standalone performance, particularly in terms of sensitivity at the ≥ 9.8 threshold, remains insufficient to confidently rule out advanced fibrosis without supplementary testing. The ELF test is best used within a two-step FIB-4 plus ELF algorithm, which not only demonstrated reliable diagnostic capabilities but also reduced the need for unnecessary liver biopsy or specialist referral by 67%-80% across cohorts. This is further supported by evidence showing ELF’s strong prognostic value for hepatic decompensation and liver related mortality[23,24].

Perhaps the most clinically pressing finding of this review is the identification of liver viscosity (Vi PLUS) as a promising noninvasive marker for necroinflammatory activity in MASLD. Vi PLUS progressively increased with both hepatocyte ballooning and lobular inflammation grades, and the viscosity-aspartate aminotransferase-speed of sound MASH ultrasound score, combining Vi PLUS, aspartate aminotransferase, and shear stiffness plane-wave ultrasound - achieved an AUROC of 0.75 for diagnosing MASH. The ability to noninvasively identify MASH without relying solely on fibrosis staging is crucial, as MASH rather than simple steatosis carries the prognostic risk of disease progression[24,25].

These findings are largely consistent with the broader evidence base, which strengthens the credibility of our conclusions. Our observation that transient elastography cannot be used as a standalone test for significant fibrosis aligns with a prior meta-analysis that also recommended its inclusion in an algorithm with serum markers. The diagnostic performance of the ELF test and its superiority to FIB-4 in predicting outcomes is supported by multiple recent studies in both clinical and general population cohorts. The identification of liver viscosity as a marker of activity is in line with work by Sugimoto et al[26] supporting the hypothesis that necroinflammatory changes affect the viscoelastic properties of liver tissue. However, our results contrast with the milestone study by Deffieux et al[27], which found viscosity to be a poor predictor of disease activity across various chronic liver diseases. A possible explanation for this discrepancy is that the association between viscosity and necroinflammatory activity appears particularly strong in MASLD compared to other etiologies. The cost-effectiveness of a primary care strategy using FIB-4/ELF, followed by specialist care VCTE/biopsy is loosely supported by earlier health economic analyses[25-28].

The variability across the included studies must be acknowledged, as it influences the interpretation and generalizability of the findings. Cohorts varied in terms of underlying liver disease etiology (e.g., MASLD, chronic hepatitis B), disease stage, and patient demographics. Most studies did not include asymptomatic individuals from the general population, limiting insights into early-stage fibrosis detection. A key source of heterogeneity was the use of different elastography devices and technologies (transient elastography, 2D-SWE, point SWE). Crucially, cutoff values for fibrosis staging are not interchangeable across devices or manufacturers, complicating clinical implementation. While liver biopsy was the common reference standard, variations in biopsy technique, sample size, and histopathological scoring systems introduce potential measurement error[29].

This review has several strengths that enhance the reliability of its conclusions, including a comprehensive search strategy across multiple databases to capture the most recent and relevant evidence, adherence to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines ensuring methodological rigor and transparency, inclusion of studies that used liver biopsy as the reference standard thereby minimizing verification bias, and a clinical and practical focus that extended beyond diagnostic accuracy to consider practical limitations, prognostic utility, and the rationale for sequential testing algorithms feasible in real world clinical pathways.

However, limitations inherent to the included studies and this review should be considered. The overall sample size across studies was modest (< 1000 patients for many comparisons). Furthermore, the lack of studies involving asymptomatic, general population cohorts limits our ability to assess the utility of these tests for early detection in unselected individuals. Although our search was broad, we cannot rule out the possibility of publication bias, and the review was restricted to English language publications, which may have excluded relevant data. Promising findings, such as those for liver viscosity (Vi PLUS), are based on proprietary measurements from specific ultrasound systems (e.g., Aixplorer MACH 30) and derived from single center cohorts, which limits immediate clinical applicability and underscores the need for independent validation.

These findings have important implications for clinical practice and future research. For clinical practice, a sequential diagnostic pathway starting with FIB-4, followed by the ELF test for indeterminate cases, and then elastography (preferably transient elastography or 2D-SWE) for high-risk patients represents a cost-effective and accurate strategy for fibrosis staging. Clinicians must be aware of the limitations of each test, particularly device specific cutoffs and confounding factors like acute inflammation. Future studies should focus on validating noninvasive tests for long-term monitoring of antiviral treatment efficacy and cirrhosis complications, conducting genetic studies to identify patients at high risk for progression to end-stage liver disease, determining the optimal, standardized algorithm for staging and prognosis across different liver disease etiologies and healthcare settings, and pursuing independent, multicenter validation of novel biomarkers like liver viscosity across different device platforms.

CONCLUSION

In conclusion, eight non-invasive techniques have been identified in this study: ELF, FIB-4, NFS, liver viscosity, transient elastography, 2D-SWE, ARFI based techniques and VCTE. Compared to liver biopsy, these tests are reliable and have a good clinical applicability in diagnosing and staging liver fibrosis and steatosis. No single test can replace biopsy however a multi-step sequential diagnostic algorithm approach integrating serum biomarkers and imaging modalities shows good results. The best algorithm starts with FIB-4 followed by ELF and then elastography. Their sequential combination, which is mindful of device specific cut-offs and patient specific confounding factors offers the most promising results. Future work must address the existing heterogeneity and technical limitations to pave the way for standardized, widely accessible non-invasive liver disease management.

However, the available evidence is limited by small predominantly single-center cohorts, heterogeneity in study populations and cut-off values, and limited inclusion of early and symptomatic disease. Future research should prioritize large, prospective studies to standardize thresholds across platforms, validate widely applicable diagnostic algorithms, and expand the role of invasive tools in early detection, longitudinal monitoring and prognostication.

ACKNOWLEDGEMENTS

We thank the Research MD to help us with their guidance on doing this project.