Blood tests can give us useful clues about how the liver is coping. One abnormal result does not automatically mean that there is serious liver disease. It is usually the overall pattern of the blood results, along with symptoms, medications, alcohol intake, diet and general health, that gives the clearest picture.
Gamma GT – GGT
Gamma GT, usually written as GGT, is an enzyme linked with the liver and bile ducts.
A raised GGT can be a sign that the liver is under extra pressure, but GGT is quite sensitive and can increase for many different reasons.
These may include:
- Fatty liver
- Alcohol intake
- Certain medications
- Some supplements
- Being overweight, particularly carrying weight around the middle
- High blood sugar or insulin resistance
- Problems affecting the gallbladder or bile ducts
- Other liver conditions
For example, a GGT result of 60 U/L may be only mildly raised, depending on the person’s sex and the laboratory reference range.
Rather than looking at GGT on its own, doctors will usually look at other liver blood tests as well.
ALT and AST
ALT and AST are enzymes found inside cells.
When liver cells become irritated or damaged, more of these enzymes can enter the bloodstream.
Raised ALT or AST can occur with:
- Fatty liver
- Alcohol-related liver irritation
- Some medications
- Viral infections
- Other causes of liver inflammation
AST can also rise after muscle injury or very strenuous exercise, so it is not specific to the liver.
ALP
ALP can give information about the liver and bile ducts.
When both ALP and GGT are raised, doctors may look more closely at the gallbladder, bile ducts and the way bile is flowing from the liver.
ALP can also come from bone, so the result always needs to be interpreted alongside other blood tests.
Bilirubin
Bilirubin is a yellow substance produced when old red blood cells are broken down.
The liver normally processes bilirubin and helps remove it from the body.
Raised bilirubin can sometimes cause:
- Yellowing of the skin or eyes
- Dark urine
- Pale stools
- Itching
A raised bilirubin result may need further investigation, particularly when other liver or bile-duct tests are also abnormal.
Albumin
Albumin is a protein made by the liver.
It helps keep fluid in the bloodstream and carries many substances around the body.
A persistently low albumin level can sometimes indicate that the liver is not producing proteins as well as it should, although low albumin can have other causes too.
Platelets
Platelets help our blood to clot.
A low platelet count can sometimes be seen in people with longstanding liver disease, particularly when there is scarring of the liver.
One slightly low result does not diagnose liver disease, but it may encourage the doctor to investigate further.
INR and Blood Clotting
The liver makes many of the proteins needed for normal blood clotting.
A test called INR, or prothrombin time, can help show how well this part of liver function is working.
If INR becomes significantly raised without another explanation, further medical assessment may be needed.
Looking at the Bigger Picture
Liver health is rarely judged from one blood result alone.
Doctors may also look at:
- Cholesterol and triglycerides
- Fasting blood glucose
- HbA1c
- Weight and waist measurement
- Blood pressure
- Iron and ferritin levels
- Medications and supplements
- Alcohol intake
- Family and medical history
This is particularly important because fatty liver is often connected with insulin resistance, raised blood sugar, raised triglycerides and carrying excess weight around the abdomen.
Understanding Common Patterns
A raised GGT on its own may lead to a review of alcohol intake, medications, supplements and metabolic health.
Raised GGT together with ALT or AST can suggest that liver cells are irritated or inflamed.
Raised GGT together with ALP may encourage further investigation of the gallbladder, bile ducts and bile flow.
Raised bilirubin together with GGT or ALP generally needs closer medical assessment.
Changes in albumin, INR or platelet levels can be particularly important because they may give information about how well the liver is carrying out its normal functions.
The Important Message
An abnormal liver blood test is a clue rather than a diagnosis.
A mildly raised result may simply need to be repeated and monitored. Your doctor may also review medications, alcohol intake, metabolic health and lifestyle factors.
The liver has a remarkable ability to recover and repair itself when the underlying cause of the problem is identified and addressed.
Seek medical advice promptly if liver concerns are accompanied by symptoms such as yellowing of the skin or eyes, very dark urine, pale stools, severe abdominal pain, swelling of the abdomen, vomiting blood, unusual bleeding, severe drowsiness or confusion.
This information is for education and does not replace individual medical advice, diagnosis or blood-test interpretation from your GP or healthcare professional.
