How to Read Your Liver Function Test (LFT)

An LFT printout looks like a verdict. It is not. It is a snapshot of enzymes, pigments and proteins that hint whether liver cells are leaking, bile is flowing, and the organ is still manufacturing what the body needs. Reading it well means understanding patterns — and knowing what a neat set of “normals” can still miss.

Visible yellowing and its causes live in what causes jaundice in adults. Symptom-led scarring lives in warning signs of cirrhosis. Stages of fat and fibrosis live in fatty liver: when does it become serious. This article owns panel literacy — what each line means and what to do next.

What an LFT panel actually includes

Think in three baskets:

Labs print reference ranges that vary slightly by method and lab. Compare yourself to your report’s range, and prefer trends over a single spooky digit.

ALT and AST — injury enzymes

ALT (alanine aminotransferase) is relatively liver-specific. When hepatocytes are inflamed or dying, ALT rises. Mild persistent elevation is a classic early flag in metabolic fatty liver (MASLD).

AST (aspartate aminotransferase) also lives in muscle and heart. A lone AST bump after a hard gym session is not automatic liver disease. When both ALT and AST rise, liver injury is the leading explanation.

Clinicians sometimes glance at the AST:ALT ratio. A ratio above about 2:1 can suggest alcohol-related injury in the right history; ALT-predominant patterns are common in viral hepatitis and fatty liver. Ratios are clues, not courtroom evidence.

ALP and GGT — the biliary side

ALP (alkaline phosphatase) rises when bile canaliculi and ducts are irritated or blocked — and also in bone growth or bone disease. That dual origin is why we need context.

GGT helps. If ALP and GGT rise together, the ALP is likely hepatic/biliary. If ALP is high and GGT is normal, think bone (or pregnancy-related ALP) before assuming a blocked duct.

Cholestatic patterns point toward stones, strictures, drugs or infiltrative disease — often the next step is ultrasound or MRCP, not another herbal tonic. Ductal stone disease is covered separately in bile duct stones.

Bilirubin — direct vs indirect

Bilirubin is the yellow pigment from broken-down red cells. The liver conjugates it so it can leave in bile.

• Indirect (unconjugated) high → excess production (hemolysis) or slow conjugation (commonly Gilbert syndrome — usually benign).
• Direct (conjugated) high → liver cell failure to export bile, or downstream obstruction.

When totals climb enough, you see jaundice — eyes and skin yellow, urine dark, stools pale if bile never reaches the gut. The clinical story of yellowing is in the jaundice article; here the point is reading the split on the report.

Albumin and INR — is the liver still building?

Enzymes shout about leakage. Albumin and INR whisper about factory output.

Albumin has a long half-life (~three weeks), so low levels usually reflect chronic synthetic impairment, malnutrition or protein loss — not a one-day cold. INR (from prothrombin time) rises when clotting-factor production falls; those factors turn over quickly, so a climbing INR is a sharper warning in acute failure or decompensated cirrhosis.

A patient can have scary ALT with preserved albumin/INR (acute injury, still compensating) — or near-normal ALT with falling albumin and rising INR (scarred, failing synthetic function). Those are different emergencies.

Hepatocellular vs cholestatic patterns

Specialists read patterns and trends, not isolated flags. A single ALT of 55 after a viral illness is a different conversation from ALT of 800 with jaundice.

Normal LFT ≠ healthy liver

This is the sentence patients need tattooed on the report folder. Significant steatosis, bridging fibrosis and compensated cirrhosis can hide behind normal enzymes. The liver is quiet until it is not. If risk is high — diabetes, central obesity, heavy alcohol history, viral hepatitis, family disease — ask for imaging and stiffness assessment, not only a corporate health-package LFT. Alcohol dose and recovery context sit in how much alcohol is too much and what happens after you stop drinking.

Children, pregnancy and extreme exercise each tweak interpretation further. Paediatric ranges differ; pregnancy raises ALP from the placenta; a marathon can spike AST from muscle. Mention those contexts when you hand the sheet over — otherwise a normal story looks like a disease story on paper.

Common report scenarios (examples, not self-diagnosis)

These patterns show how clinicians think — your own numbers need a physician:

• Mild ALT/AST up, ALP/GGT normal, you feel fine. Often metabolic fatty liver, medication effect, or a transient viral insult. Repeat the panel, check metabolic risk, consider ultrasound if it persists.
• ALP and GGT clearly dominate. Lean biliary until imaging says otherwise — stones and strictures hide here.
• Bilirubin up with pale stools and dark urine. Treat as potential obstruction until proven otherwise — this is not a “wait and see enzymes” situation.
• Near-normal enzymes, low albumin, high INR, swollen abdomen. Synthetic failure / decompensation territory — urgency is clinical, not the ALT digit.

Printouts also hide traps: wrong units, different lab ranges, and samples drawn after intense exercise. Bring the full sheet with reference intervals.

What to do with an abnormal report

1. Do not panic over a mild one-off bump — repeat and correlate.
2. Stop alcohol while sorting it; list every medicine and supplement.
3. Skip unregulated liver tonics — they cause injury more often than they heal.
4. Expect ultrasound when abnormalities persist or the pattern is cholestatic.
5. Ask about FibroScan when fatty liver or fibrosis risk is the question — CAP for fat, kPa for stiffness.

Reversibility of early fat is covered in can fatty liver be completely reversed; this page stops at reading the bloods and choosing the next honest test.

When to see a liver specialist in Chennai

Bring the full PDF or printout with reference ranges, not a WhatsApp crop of one line. Seek sooner if enzymes stay high, bilirubin rises, albumin falls, INR climbs, or you develop jaundice, swelling, confusion, vomiting blood or black stools. Evaluation may lead toward medical hepatology, HPB imaging, or — when anatomy and function fail — liver transplant pathways. A single abnormal corporate health check is a starting signal, not a complete work-up — ask what the next test should be before the next annual package.

Book an appointment or call +91 99626 60009.

This article is general information, not personal medical advice. Lab reference ranges differ between laboratories. Seek urgent care for jaundice with confusion, vomiting blood, black stools, or severe abdominal pain with fever.