You have had a liver function test. One or more results are outside the reference range.
Now you may be wondering whether you need an ultrasound, a FibroScan, or another liver test. These tests are related, but they do not answer the same question.
An LFT examines blood markers. An ultrasound looks at the liver’s structure. A FibroScan estimates liver stiffness and fat. The right test depends on your symptoms, risk factors, and earlier results.
Start with the basic difference
An LFT is also called a liver profile or liver panel. The exact tests included can vary between laboratories. Most panels include markers such as ALT, AST, bilirubin, ALP, GGT, albumin, and total protein.
For a clearer explanation of the terminology, read LFT vs Liver Profile vs Liver Panel. The package name matters less than the individual tests included in the report.
An ultrasound and a FibroScan are imaging-based tests. They do not replace an LFT. Instead, they provide different information about the liver.
LFT, ultrasound and FibroScan compared
| Test | What it mainly checks | What it may help identify | Main limitation |
|---|---|---|---|
| LFT or liver profile | Blood markers linked to liver injury and function | Raised ALT, AST, bilirubin, ALP, GGT, or low albumin | Cannot measure liver fat or scarring by itself |
| Abdominal ultrasound | Liver and abdominal structure | Fatty appearance, gallstones, bile-duct changes, some masses | May not detect early fibrosis accurately |
| FibroScan | Liver stiffness and fat-related measurements | Fibrosis risk and liver fat | Does not explain every cause of an abnormal LFT |
| FIB-4 score | Estimated fibrosis risk using blood results and age | Low, intermediate, or higher fibrosis risk | It is an estimate, not a direct scan |
| Liver biopsy | Liver tissue under a microscope | Inflammation, fat, and scarring in selected cases | Invasive and not needed for most people |
These tests are often used together. A blood test may lead to an ultrasound. An ultrasound may then lead to a FibroScan or another fibrosis assessment.
What does an LFT tell you?
An LFT measures substances in your blood that may reflect liver-cell injury, bile flow, bilirubin processing, or protein production.
Common LFT markers include:
- ALT or SGPT.
- AST or SGOT.
- Alkaline phosphatase or ALP.
- Gamma-glutamyl transferase or GGT.
- Total and direct bilirubin.
- Albumin.
- Total protein.
- Sometimes globulin and other markers.
A high ALT or AST may suggest liver-cell injury. A high ALP, GGT, or bilirubin may point towards a bile-flow problem. Low albumin can have several causes and does not automatically mean advanced liver disease.
An LFT provides clues. It does not show the physical appearance of your liver.
Can an LFT detect fatty liver?
An LFT may provide clues about fatty liver, but it cannot confirm it on its own.
Some people with fatty liver have raised ALT or AST. Others have completely normal liver enzymes. This is why a normal LFT does not always rule out fatty liver or early liver disease.
If fatty liver is suspected, your doctor may consider an abdominal ultrasound, FibroScan, or another assessment. Blood sugar, HbA1c, cholesterol, triglycerides, weight, and waist circumference may also be relevant.
The Mayo Clinic guide to fatty liver diagnosis explains how doctors may combine blood tests, ultrasound, transient elastography, and other investigations.
What can an abdominal ultrasound show?
An abdominal ultrasound uses sound waves to create images of the liver and nearby organs. It does not involve radiation.
It may help identify:
- A fatty appearance of the liver.
- Gallstones.
- Enlargement of the liver.
- Changes in the gallbladder.
- Bile-duct dilation.
- Some cysts or masses.
- Other abdominal findings.
Ultrasound is often used when liver disease is suspected. It can be especially useful when a doctor wants to look at the liver’s structure or check for gallbladder and bile-duct problems.
However, a standard ultrasound cannot reliably measure the full amount of liver scarring. It may also miss early changes.
What is a FibroScan?
FibroScan is a non-invasive liver assessment. It uses ultrasound-based technology to measure liver stiffness.
Liver stiffness may increase when fibrosis, or scar tissue, develops. FibroScan can also provide a measurement related to liver fat.
The test is usually:
- Quick.
- Painless.
- Non-invasive.
- Performed without a needle.
- Suitable for many people with suspected chronic liver conditions.
The Leeds Teaching Hospitals guide to FibroScan explains that the test can assess both liver stiffness and liver fat. It also notes that FibroScan may be used with blood tests, other scans, or a biopsy.
FibroScan does not identify every cause of liver disease. Its results should be reviewed with your LFT, medical history, symptoms, and other investigations.
What does liver stiffness mean?
A healthy liver is generally soft and flexible. Repeated injury can lead to fibrosis. Over time, more advanced fibrosis can make the liver stiffer.
A higher FibroScan reading may indicate a higher risk of scarring. But the result is not interpreted in isolation.
Liver stiffness can sometimes be affected by factors such as:
- Recent food intake.
- Liver inflammation.
- Bile-flow problems.
- Congestion.
- Technical limitations.
- Body shape.
- The quality of the scan readings.
The Mayo Clinic explanation of ultrasound elastography notes that slightly raised stiffness may sometimes require a repeat scan, while very high readings may need further testing and imaging.
When might you need a FibroScan?
A doctor may consider FibroScan when there is concern about liver fibrosis or long-term liver injury.
This may include:
- Persistently high ALT or AST.
- Fatty liver seen on ultrasound.
- Type 2 diabetes.
- Obesity or increased waist circumference.
- High triglycerides or cholesterol.
- Chronic hepatitis B or hepatitis C.
- Regular heavy alcohol use.
- A history of liver disease.
- A family history of advanced liver disease.
- An uncertain or intermediate FIB-4 score.
Not everyone with a mildly abnormal LFT needs a FibroScan. The decision depends on the complete clinical picture.
What is a FIB-4 score?
FIB-4 is a calculation used to estimate the risk of liver fibrosis. It uses factors such as:
- Age.
- AST.
- ALT.
- Platelet count.
It is not a scan. It does not directly measure liver stiffness. It helps doctors decide whether further evaluation may be useful.
A low-risk score may reduce the need for immediate specialist testing. An intermediate or higher-risk score may lead to a FibroScan or another assessment.
The score should be interpreted carefully. Age and other health conditions can affect its meaning.
Which test may be used in different situations?
| Situation | Test a doctor may consider | Why it may be useful |
|---|---|---|
| Routine liver health check | LFT or liver profile | Provides basic blood markers |
| Mildly abnormal ALT or AST | Repeat LFT and medical review | Checks whether the change persists |
| Suspected fatty liver | Abdominal ultrasound | Looks for a fatty appearance |
| Fatty liver with diabetes or obesity | FIB-4 and possibly FibroScan | Helps estimate fibrosis risk |
| Persistent enzyme elevation | LFT, ultrasound, and further blood tests | Looks for possible causes |
| Raised bilirubin or jaundice | LFT and imaging if advised | Assesses bilirubin and bile flow |
| Suspected gallstones | Abdominal ultrasound | Examines the gallbladder and bile ducts |
| Chronic hepatitis | Blood tests and fibrosis assessment | Monitors liver injury and scarring risk |
| Unclear or conflicting results | Doctor-directed investigations | Helps avoid relying on one test |
This table is a general guide. Your doctor may recommend a different sequence based on your symptoms and medical history.
What if your LFT is abnormal?
Do not assume that an abnormal result means cirrhosis or liver failure.
ALT, AST, bilirubin, ALP, and GGT can change for many reasons. These may include recent illness, medicines, supplements, alcohol, intense exercise, or liver conditions.
Read What High ALT, AST, Bilirubin and GGT May Mean before trying to interpret one flagged result. It explains why doctors look at the pattern and degree of change rather than one number alone.
For a deeper explanation of how high is “too high,” see How Much Is Too Much for Your Liver?.
Your doctor may recommend:
- Repeating the LFT.
- Reviewing medicines and supplements.
- Testing for hepatitis B or hepatitis C.
- Checking blood sugar and HbA1c.
- Checking cholesterol and triglycerides.
- Having an abdominal ultrasound.
- Calculating a FIB-4 score.
- Having a FibroScan.
- Seeing a gastroenterologist or hepatologist.
How Metro life fits into the picture
Metro life often leaves little room for regular health routines. A typical day may involve an early start, a long commute, desk work, meals between meetings, and a late return home.
Exercise may be limited to weekend plans. Sleep may be inconsistent. Restaurant meals, sugary drinks, alcohol, and unmonitored supplements can become part of the routine.
These habits do not automatically cause liver disease. But they can add to risks such as weight gain, diabetes, high cholesterol, and fatty liver.
Read Can Your Daily Metro Routine Affect Your Liver? for a closer look at these everyday risk factors.
Do you need to fast before a FibroScan?
Preparation instructions can vary between centres and machines. Some providers ask patients to avoid food for a period before the scan because eating can affect liver blood flow and stiffness measurements.
Always follow the instructions from the diagnostic centre or your doctor. Ask whether you should:
- Fast before the appointment.
- Continue your regular medicines.
- Drink water.
- Avoid alcohol or strenuous exercise.
- Bring previous LFT or ultrasound reports.
Do not guess the preparation requirements from another person’s appointment.
When should you seek medical advice quickly?
Arrange medical advice promptly if you have an abnormal liver test along with:
- Yellowing of the eyes or skin.
- Very dark urine.
- Pale stools.
- Severe or persistent abdominal pain.
- Repeated vomiting.
- Increasing abdominal swelling.
- Confusion or unusual drowsiness.
- Unusual bleeding or easy bruising.
- Vomiting blood.
- Black, tar-like stools.
Severe symptoms may require urgent medical care. Do not wait for a routine scan appointment if you feel seriously unwell.
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