Fatty Liver Disease: How Blood Tests Detect It Before Symptoms Appear

Quick answer

Fatty liver disease means fat has built up inside your liver cells. It is often caused by insulin resistance, a diet high in refined carbs and sugar, alcohol, or metabolic syndrome. The earliest blood signs are a mildly high ALT (called SGPT on most Philippine lab reports) and GGT, often paired with high triglycerides and insulin. Most early stage fatty liver can improve with lifestyle changes within 6 to 12 months.

What fatty liver disease is

Doctors call fatty liver "hepatic steatosis." This means fat has built up in your liver cells, making up more than about 5% of your liver's weight. The disease moves through stages.

Simple steatosis (NAFL)

• Fat sits inside liver cells.
• There is no major swelling or damage yet.
• This stage usually improves with lifestyle change.

Non-alcoholic steatohepatitis (NASH)

• Fat is joined by swelling and cell injury.
• It can move on to scarring, called fibrosis.
• This stage can still improve with strong lifestyle change.

Fibrosis

• Your liver tissue starts to scar.
• Doctors grade this from F1 to F4, with F4 being the worst.
• Early stages can partly heal.

Cirrhosis

• This is heavy, advanced scarring that blocks normal liver function.
• It rarely fully heals.
• It raises the risk of liver failure and liver cancer.

Most people with fatty liver never move past the first stage. But some people, especially those with metabolic syndrome, do move on to NASH and beyond.

Why fatty liver is rising in Asia

Fatty liver now affects an estimated 25 to 30% of adults around the world, and even more in some Asian groups. Several things drive this:

• Rising obesity and metabolic syndrome.
• Diets high in refined carbs, such as white rice meals and sweet drinks.
• Sitting for long hours without much movement.
• Sugar, especially fructose, which your liver has to process on its own.
• Rising rates of type 2 diabetes.

There is also a pattern called "lean NAFLD." This affects Asian adults at a normal weight. It is often driven by fat stored deep around the organs, and by genes.

The blood tests that detect fatty liver

ALT (alanine aminotransferase)

Standard range: up to 40 U/L. Healthy target: under 25 for women, under 30 for men.

ALT (SGPT) is a liver enzyme, a protein your liver uses to do its job. It is the most useful early warning sign for fatty liver. A mild rise, 28 to 50 U/L, in someone with no symptoms is one of the most common first clues.

AST (aspartate aminotransferase)

Standard range: up to 40 U/L. Healthy target: similar to ALT.

AST (called SGOT on most Philippine lab reports) tends to rise later than ALT in fatty liver. Doctors compare AST to ALT as a ratio:

• AST/ALT under 1: typical of fatty liver.
• AST/ALT over 1: may point to alcohol related liver damage, or scarring.

GGT (gamma-glutamyl transferase)

Standard range: up to 50 to 60 U/L. Healthy target: under 25 U/L.

GGT rises with fatty liver. It is also sensitive to alcohol and to certain medicines. A high GGT together with a high ALT is a strong signal for fatty liver.

ALP (alkaline phosphatase) and bilirubin

These usually stay normal in early fatty liver. If they are off, it may point to a different liver problem, or a more advanced stage.

Albumin and INR

These show how well your liver makes key proteins and clotting factors. They usually only change once the disease is advanced.

Fibrosis scores (calculated from your results)

• FIB-4 score. Uses your age, ALT, AST, and platelet count to estimate scarring risk.
• NAFLD Fibrosis Score (NFS). Adds your BMI, diabetes status, and albumin.
• APRI. Uses AST and platelet count.

These scores use numbers already on a full panel. They give useful clues about scarring risk without needing a scan.

Common patterns

Pattern 1: Early fatty liver

• ALT 28 to 45 U/L.
• GGT 25 to 40 U/L.
• High triglycerides.
• High fasting insulin.
• Often paired with extra belly fat.
• What to do: change your lifestyle. This stage usually improves.

Pattern 2: Possible NASH

• ALT 50 to 100 or higher.
• High GGT.
• AST/ALT ratio moving toward 1.
• High FIB-4 score.
• What to do: see a doctor. Imaging or a specialist visit may follow.

Pattern 3: Advanced disease

• AST/ALT over 1.
• Low platelet count.
• High FIB-4, over 2.67 means a high chance of scarring.
• What to do: see a liver specialist. Imaging, and sometimes a biopsy, may be needed.

Pattern 4: Alcohol related pattern

• GGT very high.
• AST/ALT ratio over 2 to 1.
• High MCV, a red blood cell size marker.
• What to do: cut back on alcohol, and see a doctor.

Imaging: the next step after blood work

Blood tests show your body's chemistry. Imaging shows the fat itself.

• Abdominal ultrasound. The first choice. It is widely available and can spot liver fat once it reaches about 30% or more.
• Transient elastography. This measures how stiff your liver is, which points to scarring. It also estimates fat.
• MRI proton density fat fraction (MRI-PDFF). The most accurate option. Mostly used in specialist centers and research.

Most people with high ALT and GGT do not need a biopsy. Imaging plus the calculated fibrosis scores usually give enough information.

How to help reverse fatty liver

The good news is that early stage fatty liver often improves a lot. These steps have the strongest evidence behind them.

1. Lose weight, the single most powerful step

• Losing 5% of your body weight can lower liver fat.
• Losing 7% often clears up NASH.
• Losing 10% can help reverse scarring.

2. Cut refined carbs and sugar, especially fructose

This is the most useful diet change you can make:

• Cut out sweet drinks.
• Eat less white rice, bread, and instant noodles.
• Avoid added sugar and high fructose corn syrup.
• Cut back on alcohol, or stop.

3. Move more

• Aim for 150 or more minutes of aerobic exercise each week.
• Add 2 to 3 strength sessions a week.
• Both lower liver fat, even without weight loss.

4. Try a Mediterranean style diet

• Eat more vegetables, fruit, fish, olive oil, nuts, and beans.
• This diet pattern improves liver markers and slows disease.

5. Coffee, a surprising helper

Studies link regular coffee, 3 or more cups a day, to slower fatty liver progress.

6. Vitamin E, for some patients

There is some evidence it helps NASH in people without diabetes. Ask your doctor first.

7. Newer medicines

• GLP-1 drugs, such as semaglutide and tirzepatide, have shown they can lower liver fat.
• Some drugs made just for NASH are approved or close to approval.
• Talk with a liver specialist about these options.

8. Treat conditions that make it worse

• Manage diabetes well.
• Statins can help lower ApoB, and may protect the liver in fatty liver disease.
• Treat sleep apnea if you have it.
• Cut back on medicines that stress the kidneys, when possible.

When to retest

After making lifestyle changes, retest at 12 weeks. ALT and GGT usually respond by then.

For ongoing checks, test every 6 months until your numbers are normal. After that, once a year is enough. If you want a clear baseline to track against, you can book a full panel here.

How &you Labs reports your liver markers

Every &you Labs panel checks ALT, AST, GGT, ALP, bilirubin, albumin, total protein, and platelets. Your FIB-4 score is worked out for you automatically. Your report reads these together with your metabolic markers, such as fasting insulin, HbA1c, and triglycerides, since fatty liver rarely shows up alone. You can see the full list of markers we test on our biomarker page.

Frequently asked questions

What does SGPT mean in a blood test?

SGPT is the older name for ALT, a liver enzyme. Most Philippine labs still print SGPT on the report, so the two mean the same thing. A high SGPT is often the first sign of fat in the liver. The healthy target is under 25 U/L for women and under 30 U/L for men.

Is SGOT the same as AST?

Yes. SGOT is the older name for AST, another liver enzyme. In fatty liver, SGOT usually rises later than SGPT. Doctors read the two together as a ratio.

My ALT is 32. Is that fatty liver?

By the standard range, up to 40, this counts as "normal." By the healthy target, under 25 for women and under 30 for men, it is mildly high. If it comes with other signs, such as high triglycerides, high insulin, or extra belly fat, it is worth asking your doctor about an ultrasound.

Can I have fatty liver without being overweight?

Yes. This is called "lean NAFLD." It affects Asian adults at a normal weight. Fat stored deep around the organs, genes, and diet all play a part.

How fast can ALT improve?

Most people see a real drop in ALT within 6 to 12 weeks of steady lifestyle change.

Is alcohol always the cause?

No. Fatty liver, or NAFLD, is defined as liver fat without heavy alcohol use. Alcohol causes a related but separate condition. Many people have a mix of both factors.

Do I need a liver biopsy?

Most people with fatty liver do not. Imaging, such as an ultrasound or a liver elastography scan, plus the calculated fibrosis scores, usually give enough information. A biopsy is saved for cases where the diagnosis is unclear.

Key takeaways

• Fatty liver disease, or NAFLD, is now the most common long term liver condition, and it is rising fast across Asia.
• Early signs include a mildly high ALT, 28 to 45, and GGT, often with high triglycerides and fasting insulin.
• The AST/ALT ratio and FIB-4 score help show how far the disease has moved along.
• Most early stage fatty liver improves with weight loss, less sugar and refined carbs, exercise, and less alcohol.
• "Lean NAFLD" can affect people at a normal weight, so do not rule it out based on weight alone.