Raised liver enzymes: what abnormal liver blood tests mean and what happens next

Liver enzymes are proteins made in liver cells that appear in small amounts in the blood. A liver blood test, often called a liver function test or LFT, measures several of them together with bilirubin and proteins. When liver cells are inflamed or damaged, or when bile flow is blocked, some of these enzymes rise.

A raised level is a signal, not a diagnosis. Lab Tests Online UK, which is written by UK laboratory professionals, stresses that abnormal results can occur in conditions that do not involve the liver or bile ducts, and that normal results can be found in people with serious liver disease. A single abnormal result is therefore usually the start of a conversation with a GP rather than a reason for alarm.

Lab Tests Online UK describes a liver panel as up to five tests measured at the same time on a blood sample, with others added when needed. The pattern of results matters more than any single number.

The NHS names three main causes of liver disease: obesity, an undiagnosed hepatitis infection and alcohol misuse. In everyday practice, raised enzymes most often reflect one of the following.

• Non-alcoholic fatty liver disease, where fat builds up in the liver. The NHS says you are more likely to get it if you are overweight, particularly with fat around the waist, have type 2 diabetes, polycystic ovary syndrome, high blood pressure or high cholesterol, or are over 50.

• Alcohol-related liver disease, which the NHS says develops over months or years of drinking too much. Regularly drinking just over the recommended levels can be harmful.

• Viral hepatitis, which the NHS lists as a possible cause of liver disease.

• Medicines, over-the-counter products and supplements. Lab Tests Online UK gives excessive paracetamol, and paracetamol combined with alcohol, as examples of severe liver damage.

• Inherited and immune conditions such as haemochromatosis and primary biliary cholangitis, which the NHS lists among types of liver disease. Lab Tests Online UK also names Wilson's disease and alpha-1 antitrypsin deficiency as inherited conditions.

• Causes outside the liver, such as muscle damage from severe exercise, shock, burns, severe infection, trauma or pregnancy, which Lab Tests Online UK says can make liver blood tests abnormal.

A GP will ask about symptoms, alcohol, medicines, supplements, family history and risk factors for hepatitis, and may check height, weight and waist measurement. The NHS says they may arrange more blood tests and sometimes scans such as an ultrasound of the tummy to confirm a build-up of fat, rule out other causes, find out whether there is damage to the liver and check for linked conditions.

Lab Tests Online UK notes that, depending on the history, examination and results, further tests may include hepatitis virus antibodies, iron studies, and tests for autoimmune or inherited conditions, and sometimes imaging. Repeat testing is common because some rises settle on their own, for example after an illness or a change in medication.

If you have fatty liver, the NHS says that apart from healthy lifestyle changes you will not need any other treatment unless the condition has progressed and you have liver damage, and you should have check-ups at least once a year and tests every 2 to 3 years to monitor your condition. If alcohol is involved, the NHS recommends no more than 14 units a week, spread across 3 days or more.

The NHS advises asking for an urgent GP appointment or contacting NHS 111 if your skin or the whites of your eyes look yellow, particularly with itchy skin, darker urine or paler stools than usual.

If you are worried alcohol may be affecting your liver, the NHS says to call 999 or go to A&E if you vomit blood, your stools are black and sticky, you have pain in your tummy, you have difficulty breathing, or you feel suddenly confused, dizzy or have difficulty staying awake. Do not drive yourself.

Other symptoms of more advanced liver disease listed by the NHS include persistent tiredness and weakness, loss of appetite, weight loss, itchy skin and feeling or being sick.

The NHS says you can reduce your risk of many types of liver disease by trying to maintain a healthy weight and not drinking too much alcohol, and that vaccines are available for hepatitis A and hepatitis B for people at risk. It also notes that some types of liver disease, such as alcohol-related liver disease, may improve if you stop drinking.

Tell any doctor or pharmacist about every medicine and supplement you take, and avoid exceeding the dose on paracetamol packs. Do not stop a prescribed medicine because of a raised liver test without advice, because the GP will weigh the benefit against the risk.

Liver blood tests are routine in NHS primary care. A GP can repeat them, arrange an ultrasound and refer to a hepatology or gastroenterology clinic when the cause is unclear or results are persistently abnormal.

Private blood tests and scans are available without a referral, and some people use them for convenience or reassurance. The tests are the same, but the result still needs to be interpreted in context and shared with your GP so that follow-up and monitoring are organised.