Liver Function Test (LFT): Purpose, Parameters, Preparation and Results

A Liver Function Test (LFT) is a blood-test panel that measures enzymes, proteins and bilirubin associated with liver health. It can help doctors screen for possible liver or bile-duct problems, investigate symptoms, monitor an existing liver condition and assess the effects of certain medicines.

Dr Lal PathLabs Liver Function Test (LFT) includes 12 parameters. No special preparation is required, and reports are processed daily. However, patients should follow any additional instructions provided by their doctor.

What Does the Liver Do?

The liver performs several essential functions, including:

• Processing nutrients from food
• Producing proteins such as albumin
• Producing bile to support fat digestion
• Processing medicines
• Helping regulate blood glucose and cholesterol
• Storing certain vitamins and minerals
• Removing bilirubin and other waste products from the blood

Because the liver has many different roles, one test cannot measure every aspect of its health. An LFT combines multiple markers to provide a broader picture.

What Does the Liver Function Test Measure?

Dr Lal PathLabs Liver Function Test includes the following 12 parameters:

Parameter	What it may indicate
SGOT/AST	An enzyme found in the liver, muscles and other tissues; an increase may occur with liver or muscle injury
SGPT/ALT	An enzyme found mainly in the liver; increased levels may indicate liver-cell injury
AST:ALT Ratio	Compares the AST and ALT results and may help a doctor evaluate the pattern of enzyme elevation
Alkaline Phosphatase (ALP)	An enzyme associated with the liver, bile ducts and bones
GGTP/GGT	An enzyme that may increase in some liver and bile-duct conditions
Bilirubin Total	Measures the total amount of bilirubin in the blood
Bilirubin Direct	Measures bilirubin that has been processed by the liver
Bilirubin Indirect	Represents bilirubin that has not yet been processed by the liver
Protein Total	Measures the combined amount of albumin and globulins
Albumin	Measures a major protein produced by the liver
Globulin, Calculated	Estimates a group of proteins involved in functions including immunity
A/G Ratio	Compares albumin with globulin levels

These values are assessed together. A single high or low result may have several possible explanations and should not be interpreted in isolation.

When Is an LFT Recommended?

A doctor may recommend an LFT to:

• Investigate symptoms suggesting a liver or bile-duct problem
• Screen people with risk factors for liver disease
• Assess possible hepatitis or fatty liver disease
• Monitor a known liver condition
• Evaluate the effect of treatment
• Monitor medicines that may affect the liver
• Investigate previously abnormal liver enzymes
• Assess liver health before certain treatments or procedures

Testing may be considered more often in people with obesity, diabetes, high triglycerides, regular or heavy alcohol consumption, viral-hepatitis risk, a family history of liver disease or prolonged use of certain medicines.

Some liver conditions do not cause obvious symptoms in their early stages. Therefore, a doctor may recommend testing based on risk factors or another abnormal result even when a person feels well.

Symptoms That May Require a Liver Test

Consult a doctor if you experience:

• Yellowing of the skin or eyes
• Dark-coloured urine
• Pale or clay-coloured stools
• Persistent tiredness
• Loss of appetite
• Nausea or vomiting
• Pain or discomfort in the upper-right abdomen
• Unexplained itching
• Swelling in the abdomen, feet or legs
• Easy bruising or bleeding
• Unexplained weight loss
• Confusion or unusual sleepiness

These symptoms can have causes unrelated to the liver. Clinical assessment and suitable tests are required to identify the cause.

Seek urgent medical assistance for severe abdominal pain, vomiting blood, black stools, marked confusion, loss of consciousness or rapidly worsening jaundice.

How Is the Liver Function Test Performed?

An LFT requires a blood sample, usually collected from a vein in the arm. The collection process generally takes only a few minutes.
Mild discomfort, bruising or tenderness can occasionally occur at the needle site. Serious complications from routine blood collection are uncommon.

Is Fasting Required for an LFT?

No special preparation is required for this panel.

However, fasting may be needed if an LFT is being performed with other investigations, such as fasting glucose or a lipid profile. Follow the instructions given for the complete test order.

How Are LFT Results Interpreted?

FT interpretation depends on the combination and degree of abnormal results rather than one number alone.

High ALT or AST

ALT and AST may enter the blood when cells are injured. ALT is more closely associated with the liver, while AST is also found in muscles and other organs. Increased values may occur with viral hepatitis, fatty liver disease, alcohol-related injury, medicine-related injury or other conditions.

AST or ALT levels alone do not establish the cause or measure the full severity of liver disease.

High ALP or GGT

ALP may increase in liver or bile-duct disorders, but it can also rise because of bone-related conditions. GGT can help a doctor assess whether an abnormal ALP result may be related to the liver or biliary system.

High Bilirubin

Bilirubin is produced during the normal breakdown of red blood cells. The liver processes bilirubin so it can be removed from the body.
Increased bilirubin may occur because of liver-cell injury, impaired bile flow, increased red-cell breakdown or certain inherited conditions. High bilirubin can lead to jaundice, but the cause requires medical evaluation.

Low Albumin

Albumin is produced by the liver, but a low result is not specific to liver disease. It may also occur with kidney disease, inflammation, poor nutrition, intestinal protein loss or other health conditions.

Abnormal Protein, Globulin or A/G Ratio

Changes in total protein, globulin or the albumin-to-globulin ratio may occur with liver, kidney, inflammatory, immune or nutritional conditions. These results must be evaluated with other laboratory findings.

Can an LFT Diagnose Fatty Liver or Hepatitis?

An LFT can identify an abnormal pattern that may suggest liver injury, but it cannot independently confirm fatty liver disease or identify the type of viral hepatitis.

Depending on the findings, additional investigations may include:

• Hepatitis B or hepatitis C tests
• Ultrasound or other imaging
• Complete Blood Count
• Prothrombin Time/INR
• Blood glucose and lipid testing
• Autoimmune or metabolic tests
• Other tests selected according to the suspected condition

Liver enzymes can sometimes remain within their reference ranges despite an existing liver condition. Diagnosis should therefore not depend on an LFT alone.

How to Support Liver Health?

Practical measures that may help protect the liver include:

• Avoiding or limiting alcohol
• Maintaining an appropriate body weight
• Exercising regularly
• Managing diabetes, cholesterol and blood pressure
• Taking medicines only as directed
• Avoiding unverified “liver detox” remedies
• Not sharing needles or personal items that may carry blood
• Following recommended hepatitis vaccination and testing advice
• Eating a balanced diet and limiting highly processed foods

Book a Liver Function Test

The Liver Function Test can help assess liver-associated enzymes, proteins and bilirubin in one blood sample. It may be used for screening, symptom evaluation and treatment monitoring.

Book a Liver Function Test (LFT) with Dr Lal PathLabs and consult a doctor for personalised interpretation of the results.
This information is intended for general awareness and is not a substitute for professional medical advice, diagnosis or treatment. Test availability, preparation requirements and reference intervals should be confirmed from the current laboratory report and test instructions.