Fatty liver disease can show up in blood work, but it doesn’t always. Standard blood tests detect elevated liver enzymes in many people with the condition, yet roughly 25% of people with fatty liver have completely normal enzyme levels. This means blood work is a useful starting point, not a definitive test. Imaging, such as ultrasound, is typically needed to confirm the diagnosis.
What Blood Work Actually Measures
The two liver enzymes most relevant to fatty liver are ALT and AST. These are proteins that leak into your bloodstream when liver cells are inflamed or damaged. A standard metabolic panel or liver function test will include both. When your doctor sees elevated ALT and AST on routine blood work, fatty liver is one of the first conditions they’ll consider, especially if you have metabolic risk factors like obesity, high blood sugar, or high triglycerides.
ALT tends to be more specific to the liver, while AST can also rise from muscle damage or other sources. In early fatty liver disease, ALT is usually higher than AST. When that pattern flips and AST climbs above ALT, it can signal more advanced scarring or progression toward cirrhosis. Your doctor may also check GGT, another enzyme that rises with liver stress, particularly from alcohol use or bile duct problems.
Normal Blood Work Doesn’t Rule It Out
This is the most important thing to understand. A large meta-analysis pooling data from over 4,000 patients found that 25% of people with confirmed fatty liver disease had normal ALT values. Even among those with the more severe inflammatory form (now called MASH, previously NASH), 19% had normal ALT. So if your blood work looks fine, that alone doesn’t mean your liver is healthy. Fatty liver can silently accumulate fat and even develop mild inflammation without pushing enzymes above the standard reference range.
This is partly why fatty liver disease is so underdiagnosed. Many people only discover it incidentally when they get an abdominal ultrasound or imaging for another reason.
Metabolic Markers That Raise Suspicion
Liver enzymes aren’t the only blood values that point toward fatty liver. Your lipid panel and blood sugar levels carry strong signals too. Research shows that people with fatty liver disease consistently have higher triglycerides, higher fasting blood sugar, higher LDL cholesterol, and lower HDL (“good”) cholesterol compared to those without it.
Among these markers, a few stand out as especially predictive. A triglyceride-to-HDL ratio of 1.44 or higher nearly quadruples the odds of having fatty liver. High triglycerides on their own (above about 1.61 mmol/L, or roughly 143 mg/dL) triple the risk. Elevated fasting blood sugar combined with low HDL also significantly raises the likelihood. These aren’t diagnostic on their own, but when your doctor sees this pattern alongside elevated liver enzymes, fatty liver becomes a strong working diagnosis.
Fatty liver disease has been renamed to reflect this metabolic connection. It’s now officially called metabolic dysfunction-associated steatotic liver disease, or MASLD. The new definition requires both fat in the liver and at least one cardiometabolic risk factor: things like abdominal obesity, high blood pressure, high triglycerides, low HDL, or elevated blood sugar. More than 30% of the global population meets these criteria.
Blood Tests That Check for Liver Scarring
Once fatty liver is suspected, the next concern is whether it has progressed to fibrosis, which is scarring of the liver tissue. A simple but powerful tool for this is the FIB-4 score, which your doctor can calculate from blood work you’ve probably already had done. It combines four values: your age, ALT level, AST level, and platelet count.
A FIB-4 score below 1.3 puts you in the low-risk category for advanced fibrosis. A score of 3.25 or higher suggests possible advanced scarring and warrants further evaluation. Scores between those two numbers fall into an intermediate zone that typically prompts additional testing. In one large community-based study, about 61% of patients scored in the low-risk range, 37% fell in the intermediate zone, and only 1.5% scored in the high-risk category.
Platelet count plays a key role here. Your liver helps regulate platelets, the tiny blood cells involved in clotting. As the liver scars, platelet production drops. A count below 150,000 with no other explanation is one of the laboratory findings that suggests cirrhosis.
For a more detailed look at scarring, doctors can order the Enhanced Liver Fibrosis (ELF) test. This specialized blood panel measures proteins involved in scar tissue formation. In fatty liver disease specifically, the ELF test performs well, with diagnostic accuracy ranging from 78% to 97% for detecting advanced fibrosis. It’s not available everywhere and isn’t part of a routine panel, but it can help avoid the need for a liver biopsy in some cases.
What Happens After Blood Work
Blood work is the first layer. If your results raise concern, the typical next step is imaging. An abdominal ultrasound can confirm the presence of fat in the liver. A FibroScan, which uses a specialized ultrasound technique to measure liver stiffness, gives a more precise picture of how much scarring has developed. Neither is painful, and both are done in an outpatient setting.
Liver biopsy remains the most definitive way to assess the degree of fat, inflammation, and scarring, but it’s invasive and usually reserved for cases where the diagnosis is uncertain or the doctor needs to determine exactly how advanced the disease is. For most people, the combination of blood work, a calculated fibrosis score, and imaging provides enough information to guide treatment.
If you’re getting routine blood work and notice your ALT or AST is flagged as high, or if your triglycerides and blood sugar are creeping up, those results are worth a conversation about liver health. And if your numbers look normal but you carry significant metabolic risk factors, it’s worth knowing that blood work alone might not catch what’s happening in your liver.