Introduction

The liver is one of the most hardworking organs in your body — responsible for over 500 vital functions, from detoxification to digestion and hormone regulation. Yet liver problems often go unnoticed until they become serious. A Liver Function Test (LFT) is the simplest and most accurate way to evaluate liver health. It helps detect inflammation, fatty liver, alcohol-related damage, infections like hepatitis, and even medication side effects before symptoms appear.

According to the World Health Organization, non-alcoholic fatty liver disease (NAFLD) now affects nearly 30% of the global adult population [1]. In India, sedentary lifestyles and metabolic disorders have made LFT a must-have part of every Full Body Checkup.

1. What Is a Liver Function Test (LFT)?

An LFT is a blood test panel that measures key enzymes, proteins, and substances produced or processed by the liver. Abnormal values can indicate inflammation, damage, or impaired function. The test is quick, painless, and requires no fasting in most cases.

Parameters Included in a Standard LFT:

Alanine Aminotransferase (ALT): Measures liver-cell injury. Normal range: 7–56 U/L.
Aspartate Aminotransferase (AST): Indicates liver and muscle enzyme activity. Normal: 10–40 U/L.
Alkaline Phosphatase (ALP): Reflects bile duct function; elevated in gallbladder obstruction or bone disease.
Total and Direct Bilirubin: Measures bile pigment buildup; high levels cause jaundice.
Albumin: A protein made by the liver, important for nutrient transport and tissue repair.
Gamma-Glutamyl Transferase (GGT): Sensitive marker for alcohol use and bile duct health.
Prothrombin Time (PT): Indicates blood-clotting ability; prolonged time suggests reduced liver function.

Abnormalities in two or more of these parameters often prompt further evaluation with imaging or hepatitis testing.

2. Why Is LFT Important?

The liver regulates metabolism, stores vitamins, and removes toxins. Damage to liver cells affects digestion, hormone balance, and immunity. Early LFT screening identifies issues like:

Fatty Liver Disease: Often caused by obesity, high sugar intake, or alcohol [2].
Viral Hepatitis: Infections like Hepatitis A, B, or C elevate enzymes dramatically.
Drug Toxicity: Painkillers, antibiotics, or statins can strain the liver over time.
Alcohol-Related Liver Disease (ARLD): Caused by chronic alcohol intake; GGT and AST rise disproportionately.
Autoimmune or Genetic Disorders: Such as Wilson’s disease or autoimmune hepatitis.

In India, lifestyle diseases combined with alcohol consumption make liver dysfunction one of the top ten causes of mortality [3]. Regular LFTs are therefore critical even for symptom-free adults.

3. Symptoms of Liver Dysfunction

Liver damage often starts silently, but early signs include:

Persistent fatigue and weakness
Loss of appetite or nausea
Yellowing of skin and eyes (jaundice)
Dark urine or pale stools
Abdominal bloating or pain under the ribs
Itchy skin or swelling in feet

If you experience these symptoms, an immediate LFT Test is recommended. If combined with a Liver Ultrasound, it can provide a complete liver health picture.

4. Interpreting LFT Results

Understanding LFT values helps you take proactive steps. Here’s how doctors interpret them:

Parameter	Normal Range	Meaning if High
ALT	7–56 U/L	Fatty liver, hepatitis, medication reaction
AST	10–40 U/L	Liver or heart damage, alcohol use
ALP	44–147 U/L	Bile obstruction, gallbladder issue
Bilirubin (Total)	0.1–1.2 mg/dL	Jaundice, liver inflammation
Albumin	3.5–5.5 g/dL	Low in chronic liver or kidney disease
GGT	9–48 U/L	High alcohol intake or bile injury

A mild, temporary rise may occur after heavy exercise or medication. Persistently elevated readings, however, warrant consultation and repeat testing.

5. Lifestyle Factors That Affect Liver Enzymes

Diet: Processed foods, fried snacks, and sugary drinks overload the liver.
Alcohol: The most common cause of reversible enzyme elevation.
Medications: Acetaminophen and certain antibiotics can raise ALT/AST.
Obesity and Diabetes: Insulin resistance leads to fat accumulation in the liver [4].
Sleep Deprivation: Increases oxidative stress, impairing detoxification pathways.

Adopting a Mediterranean or Indian whole-food diet — rich in vegetables, legumes, and healthy oils — can normalize enzyme levels within months.

6. How to Maintain a Healthy Liver

Eat Liver-Friendly Foods

Leafy greens (chlorophyll aids detox)
Beetroot, garlic, turmeric (natural liver cleansers)
Green tea (antioxidant EGCG reduces fat buildup)
Fruits like papaya and apple (fiber improves bile flow)

Avoid Toxins

Reduce alcohol intake, processed sugars, and avoid self-medication with over-the-counter painkillers.

Exercise Regularly

At least 30 minutes of brisk walking or yoga daily improves blood flow and reduces liver fat by up to 25% [5].

Monitor Regularly

Include an LFT Test every 6–12 months, especially if you have diabetes, obesity, or drink alcohol. Combine it with a Full Body Checkup for early detection of abnormalities.

7. FAQs

Can I take the LFT after eating?

Yes, LFTs generally do not require fasting. However, if done with lipid or glucose tests, fasting for 8–10 hours is recommended.

What causes sudden elevation in liver enzymes?

Common causes include fatty liver, viral infection, alcohol consumption, or drug toxicity. A doctor may advise repeating the test or adding imaging for clarity.

Can LFT detect liver cancer?

Not directly, but persistently high ALT, AST, and ALP along with symptoms like weight loss or jaundice may prompt further tests like alpha-fetoprotein (AFP) or ultrasound.

Liver Function Test (LFT): What It Reveals About Your Health