🫀 Men's Health

Liver Function Tests Explained

Understanding your LFT results: what each number means

Liver function tests (LFTs): also called a liver panel or hepatic function panel, are a group of blood tests that assess the health of the liver and bile ducts. They are routinely ordered before starting medications metabolised by the liver (methotrexate, statins, antiepileptics), to investigate jaundice, fatigue, right-sided abdominal pain, alcohol-related disease, and for monitoring known liver disease (hepatitis B, cirrhosis, fatty liver). In Nigeria, where hepatitis B affects 8–11% of the population and liver cancer is among the most common malignancies, LFTs are clinically vital.

Signs and Symptoms

✓ LFTs are ordered for: jaundice (yellow eyes/skin), right upper abdominal pain, unexplained fatigue, before starting certain medications, alcohol monitoring, hepatitis B/C follow-up
✓ No fasting required for basic LFTs (though GGT is affected by recent alcohol)
✓ Results usually available within 4–24 hours

Risk Factors

  • The LFT panel includes: ALT, AST, ALP, GGT, bilirubin (total and direct), albumin, total protein
  • Some labs also include LDH and prothrombin time (PT/INR) in the liver panel
  • Different tests reflect different aspects of liver function, not all elevated results mean the same thing

When to Seek Help

Bilirubin > 3x normal + symptomsClinical jaundice with dark urine and pale stools, needs urgent liver assessment
ALT > 10x normalSevere hepatocellular damage: acute hepatitis, drug toxicity, ischaemia. Urgent review
ALP > 3x normal + GGT elevatedBiliary obstruction (gallstones, cholangitis, pancreatic cancer): imaging (ultrasound) urgently
Albumin falling + prothrombin time prolongedSynthetic failure: advanced cirrhosis or acute liver failure. Emergency
Any LFT abnormality on hepatotoxic medication (paracetamol overdose, antituberculous drugs)Stop or reduce medication and seek review immediately

Tests & Diagnosis

🧪 ALT (Alanine aminotransferase)
Normal 7–56 U/L. The most specific test of liver cell damage (hepatocellular injury). Elevated in: hepatitis B/C, fatty liver, alcoholic hepatitis, drug toxicity, paracetamol overdose. Very high ALT (>10x normal) = acute hepatitis or severe drug injury
🧪 AST (Aspartate aminotransferase)
Normal 10–40 U/L. Also found in heart, muscle, kidney. Less specific than ALT for liver. AST:ALT ratio > 2:1 suggests alcoholic liver disease. Raised in hepatitis, MI, muscle damage, haemolysis
🧪 ALP (Alkaline phosphatase)
Normal 44–147 U/L. Elevated in bile duct obstruction (gallstones, cholangitis), bone disease (fractures, Paget's), and growing children (normally higher). Isolated ALP elevation with normal ALT/AST points to bile duct or bone origin
🧪 GGT (Gamma-glutamyl transferase)
Normal 8–61 U/L. Elevated by alcohol (sensitive marker), bile duct disease, fatty liver, some medications. GGT + ALP elevation = bile duct problem. GGT alone = alcohol or fatty liver
🧪 Bilirubin
Normal total < 21 µmol/L. Elevated bilirubin = jaundice when > 35 µmol/L. Pre-hepatic (haemolysis, sickle cell): indirect bilirubin high. Hepatic (hepatitis): both elevated. Post-hepatic (obstruction): direct bilirubin high + pale stools + dark urine
🧪 Albumin
Normal 35–50 g/L. Made only by the liver. Low albumin = poor liver synthetic function (cirrhosis, malnutrition, protein-losing conditions). Important marker of liver reserve
🧪 Prothrombin time (PT/INR)
The liver makes clotting factors. Prolonged PT indicates liver failure or warfarin use. INR > 1.5 in liver disease suggests significant synthetic failure

Treatment Options

1
Elevated ALT/AST: identify cause
Hepatitis B/C serology, fatty liver ultrasound, alcohol history, medication review. Treat the underlying cause
2
Hepatitis B
See hepatitis B guide: antiviral treatment (tenofovir) indicated if ALT elevated + high viral load
3
Fatty liver (NAFLD)
Weight loss, exercise, alcohol cessation, diabetes control. No specific medication currently, lifestyle is the treatment
4
Drug-induced liver injury (DILI)
Stop the offending drug if possible. Supportive care. N-acetylcysteine for paracetamol toxicity. Most cases resolve on stopping the drug
5
Bile duct obstruction
Ultrasound identifies dilated bile ducts and gallstones. ERCP or surgery for gallstone removal
6
Cirrhosis
Treat complications (ascites, variceal bleeding, hepatic encephalopathy). Monitor for liver cancer with 6-monthly ultrasound + AFP

Frequently Asked Questions

I drink herbal medicine regularly: could this affect my liver?
Yes, significantly. Many traditional herbal preparations (agbo jedi, aidan fruit, bitter leaf concoctions, certain imported supplements) are hepatotoxic. They damage liver cells. This is one of the most common causes of elevated ALT in Nigeria. Always tell your doctor about all traditional medicines. If you're on herbs and have raised LFTs, stopping them is the first intervention.
My bilirubin is slightly high but I feel fine, what does it mean?
A mildly elevated indirect bilirubin (total < 40 µmol/L, direct normal) in an otherwise healthy young person with normal ALT/AST is usually Gilbert's syndrome, a benign genetic condition where bilirubin processing is slightly slow. It causes no damage and needs no treatment. Bilirubin may rise with fasting, illness, or exertion.
Can exercise affect liver tests?
Yes. Vigorous exercise raises AST, ALT, and LDH (from muscle damage), sometimes significantly. A strenuous workout 24–48 hours before a blood test can cause misleading results. If you exercise heavily, rest for 48 hours before LFTs.
What is the difference between hepatitis and cirrhosis?
Hepatitis means inflammation of the liver: the active damage phase, usually seen as high ALT. Cirrhosis is the end result of chronic inflammation, the liver has scarred and cannot regenerate. Cirrhosis shows as low albumin, prolonged PT, thrombocytopaenia, and structural changes on ultrasound. You can have hepatitis without cirrhosis, but long-term untreated hepatitis causes cirrhosis.

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Last updated 16 October 2026.