Healthcare Provider Information about Non-Alcoholic Steatohepatitis (NASH)

NASH is a chronic liver disease characterized by liver cell injury (hepatocellular ballooning) and inflammation as a result of fatty accumulation (steatosis) seen in at least 5% of hepatocytes.

This leads to liver scarring and the development of fibrosis (scored F0 to F4). As fibrosis worsens, liver-related morbidity (including cirrhosis and hepatocellular carcinoma) and mortality increase.

Labcorp can help meet your NAFLD-NASH needs

Contact a Labcorp representative to learn more about how we can help meet your NASH and NAFLD testing needs.

Symptoms and Diagnosis of NASH

  • The symptoms of NASH may be very non-specific and can include fatigue, daytime tiredness, or abdominal pain early in the disease.
  • NAFLD patients with obesity and features of the metabolic syndrome have a higher risk of progression to NASH. Not all patients have all manifestations of the metabolic syndrome, however.
  • With the development of NASH, the cardio-metabolic profile worsens, leading to a higher risk of cardiovascular events and death.
  • It is usually discovered incidentally due to elevated liver enzymes, abnormal imaging studies or surgery.
  • As cirrhosis advances, NASH-specific symptoms are more commonly manifested.

NASH, NAFLD, & NIS4: Ask an Expert

Dr. Connelly, the lead scientist behind Labcorp's NASH and NAFLD portfolio, discusses the clinical significance of NASH and what positive NASH and liver fibrosis test results mean for patients.

Fibrosis scoring and what does it mean?

Histology is important in the evaluation of NAFLD. There have been three scoring systems for NAFLD in recent years, with the most recent being a semiquantitative scoring system validated by the National Institutes of Health–sponsored Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) in 2001. This system outlines the NAFLD activity score (NAS), a composite score of steatosis, lobular inflammation, cytological ballooning, and fibrosis (disease stage).

NASH CRN Scoring System: NAS and Fibrosis Score

Fibrosis Score 1a
Mild (delicate) zone 3 perisinusoidal fibrosis

Steatosis Grade
Degree 0
Description (%) <5

Fibrosis Score 1b
Moderate (dense) zone 3 perisinusoidal fibrosis

Steatosis Grade
Degree 1
Description (%) 5-33

Fibrosis Score 1c
Portal/periportal fibrosis only

Steatosis Grade
Degree 2
Description (%) 34-66

Fibrosis Score 2
Zone 3 perisinusoidal fibrosis with portal/periportal fibrosis

Steatosis Grade
Degree 3
Description (%) >66

Fibrosis Score 3
Bridging Fibrosis

Fibrosis Score 4
Cirrhosis

Fibrosis scoring and what does it mean?

Histology is important in the evaluation of NAFLD. There have been three scoring systems for NAFLD in recent years, with the most recent being a semiquantitative scoring system validated by the National Institutes of Health–sponsored Nonalcoholic Steatohepatitis Clinical Research Network (NASH CRN) in 2001. This system outlines the NAFLD activity score (NAS), a composite score of steatosis, lobular inflammation, cytological ballooning, and fibrosis (disease stage).

NASH CRN Scoring System: NAS and Fibrosis Score

Steatosis Grade Fibrosis Score
Degree Description (%) 0 None
0 <5 1a Mild (delicate) zone 3 perisinusoidal fibrosis
1 5-33 1b Moderate (dense) zone 3 perisinusoidal fibrosis
2 34-66 1c Portal/periportal fibrosis only
3 >66 2 Zone 3 perisinusoidal fibrosis with portal/periportal fibrosis
3 Bridging Fibrosis
4 Cirrhosis

*NASH Clinical Research Network (CRN) Scoring System