If your doctor has ordered a Liver Function Test, or LFT, you’ve probably looked at the report and wondered what all those abbreviations actually mean. Bilirubin, SGOT, SGPT — these terms can feel confusing, but each one tells your doctor something specific about how well your liver is working. This guide breaks down what a Liver Function Test measures, what each value means, and when it’s time to get one done.
What Is a Liver Function Test?
A Liver Function Test is a group of blood tests that check different substances produced or processed by the liver. Since the liver plays a central role in digestion, detoxification, and metabolism, changes in these levels can signal inflammation, damage, or an underlying liver condition — often before symptoms even appear. This is part of the broader category of liver and kidney tests commonly used for early detection.
Bilirubin: What It Measures
Bilirubin is a yellow pigment produced when your body breaks down old red blood cells. Normally, your liver processes bilirubin and removes it from your body. When the liver isn’t functioning properly, bilirubin can build up, leading to jaundice — the yellowing of skin and eyes.
Types of Bilirubin measured:
- Total Bilirubin — the overall amount in your blood
- Direct (Conjugated) Bilirubin — processed by the liver, ready to be removed from the body
- Indirect (Unconjugated) Bilirubin — not yet processed by the liver
What elevated bilirubin can indicate:
- Liver inflammation or damage
- Bile duct blockage
- Certain blood conditions affecting red blood cell breakdown
SGOT (AST): What It Measures
SGOT, also called AST (Aspartate Aminotransferase), is an enzyme found in the liver, but also in the heart and muscles. When liver cells are damaged, SGOT leaks into the bloodstream, causing levels to rise.
What elevated SGOT can indicate:
- Liver cell damage or inflammation
- Hepatitis
- Effects of certain medications or heavy alcohol use
- In some cases, muscle or heart-related causes, since SGOT isn’t liver-exclusive
SGPT (ALT): What It Measures
SGPT, also called ALT (Alanine Aminotransferase), is an enzyme found almost exclusively in the liver, which makes it a more specific marker of liver damage compared to SGOT.
What elevated SGPT can indicate:
- Liver inflammation, often linked to conditions like fatty liver or hepatitis
- Liver cell injury from infection, alcohol, or certain medications
- Ongoing liver stress that needs further evaluation if levels stay high
Doctors often look at the SGOT-to-SGPT ratio together, since the pattern between the two can offer additional clues about the underlying cause.
Normal Ranges: A Quick Reference
| Test | Typical Normal Range* |
|---|---|
| Total Bilirubin | 0.1 – 1.2 mg/dL |
| Direct Bilirubin | 0.0 – 0.3 mg/dL |
| SGOT (AST) | 5 – 40 U/L |
| SGPT (ALT) | 7 – 56 U/L |
*Reference ranges can vary slightly between labs depending on the testing method used — always refer to the range printed on your specific report rather than a general guide.
Other Values Often Included in an LFT
- Alkaline Phosphatase (ALP) — helps assess bile duct function
- Total Protein and Albumin — reflect the liver’s protein-production capacity
- GGT (Gamma-Glutamyl Transferase) — often checked alongside SGOT/SGPT for a fuller picture
Why Might Your Doctor Order an LFT?
- Routine health checkups, especially as part of a full body screening
- Unexplained fatigue, nausea, or loss of appetite
- Yellowing of skin or eyes
- Abdominal pain or swelling
- Monitoring known liver conditions like fatty liver or hepatitis
- Before starting certain long-term medications that can affect the liver
- Monitoring alcohol-related liver health
What Do Abnormal Results Mean?
It’s important to understand that a single abnormal LFT value doesn’t automatically mean serious liver disease. Levels can be temporarily elevated due to recent alcohol consumption, certain medications, intense exercise, or even a viral infection unrelated to the liver. This is exactly why your doctor interprets LFT results alongside your symptoms, medical history, and sometimes additional tests, rather than in isolation.
Persistently elevated levels, however, may point toward conditions like fatty liver, hepatitis, or other liver conditions that need further evaluation and monitoring.
How to Prepare for a Liver Function Test
- Fasting for 8-10 hours is often recommended, though your doctor will confirm if it’s required for your specific test
- Avoid alcohol for at least 24 hours before the test, as it can temporarily elevate liver enzyme levels
- Inform your doctor about any medications or supplements you’re currently taking
Get Your Liver Function Test Done at Prakash Pathology & Radiology
At Prakash Pathology & Radiology in Varanasi, our Liver Function Tests are processed with precision and reviewed carefully to give your doctor an accurate picture of your liver health. You can book an appointment online, explore our full range of pathology services, or contact us for more details.
FAQs
What is a normal SGPT level? A typical normal range is around 7-56 U/L, though this can vary slightly depending on the lab’s specific reference range.
Does high bilirubin always mean liver disease? Not always. Elevated bilirubin can be caused by liver issues, bile duct blockage, or certain blood conditions, so your doctor will interpret it alongside other findings.
Do I need to fast before a Liver Function Test? Fasting for 8-10 hours is often recommended, but it’s best to confirm with your doctor or the lab based on your specific test panel.
What’s the difference between SGOT and SGPT? SGPT is more specific to the liver, while SGOT is found in the liver as well as the heart and muscles, which is why doctors often look at both together for a clearer picture.
How often should I get a Liver Function Test done? This depends on your health history — routine checkups may include it annually, while those with known liver conditions may need more frequent monitoring as advised by their doctor.
Related Reads:
- Liver & Kidney Tests in Varanasi
- What Is a Bone Density (DEXA) Scan? Who Should Get It?
- Radiology Services — Prakash Pathology & Radiology
Need a Liver Function Test done? Book an appointment with Prakash Pathology & Radiology in Varanasi for accurate, fast results.