What Do Liver Function Test Results Mean?

A liver function test (LFT) is a blood test that measures specific proteins, enzymes, and substances produced or processed by the liver. Liver function test results can help provide insight into how well the liver is working and may highlight areas that warrant further medical advice. These tests are among the most commonly requested blood panels in the UK, both through the NHS and private clinics.

If you've recently had a liver function blood test — or you're considering one — understanding what each marker means can feel overwhelming. This guide breaks down the key biomarkers measured in a standard liver function test, explains what raised or lowered levels may suggest, and helps you decide when it might be appropriate to speak with a healthcare professional about your results.

At Private Blood Tests London, our nurse-led clinic provides liver function testing and clear, confidential reporting to help you take a more informed approach to your wellbeing.

What Is Included in a Liver Function Test?

A standard liver function test panel typically measures a group of biomarkers. Each one provides different information about liver health, bile duct function, and protein production. Here is a summary of the key markers commonly included:

Biomarker	Full Name	What It May Indicate		---	---	---		ALT	Alanine Aminotransferase	Liver cell damage or inflammation		AST	Aspartate Aminotransferase	Liver or muscle tissue damage		ALP	Alkaline Phosphatase	Bile duct function, bone health		GGT	Gamma-Glutamyl Transferase	Bile duct issues, alcohol-related changes		Bilirubin	Total Bilirubin	Red blood cell breakdown, bile processing		Albumin	Serum Albumin	Liver's protein production capacity		Total Protein	Total Serum Protein	Overall protein levels in the blood

Practical Insight: No single biomarker tells the full story. Liver function test results are most meaningful when reviewed together as a panel, giving a broader picture of liver health rather than relying on one number in isolation.

Understanding Each Liver Biomarker

ALT (Alanine Aminotransferase)

ALT is an enzyme found predominantly in liver cells. When liver cells are damaged or inflamed, ALT can leak into the bloodstream, which may result in elevated levels on a blood test. A raised ALT level is one of the more specific indicators of potential liver cell injury.

Common reasons ALT may be elevated include fatty liver changes, viral hepatitis, certain medications, and excessive alcohol consumption. However, mildly raised ALT levels can sometimes occur temporarily and may not always indicate a serious concern.

Normal reference range (approximate): 7–56 IU/L (varies by laboratory)

AST (Aspartate Aminotransferase)

AST is found in the liver but also in the heart, muscles, and kidneys. Because it is not exclusive to the liver, a raised AST level may sometimes reflect muscle injury or other non-liver causes. When both ALT and AST are elevated, this combination can provide more useful context.

Practical Insight: The ratio of AST to ALT is sometimes considered by healthcare professionals. For example, an AST/ALT ratio greater than 2:1 may sometimes be associated with alcohol-related liver changes, though this should always be interpreted by a qualified clinician.

ALP (Alkaline Phosphatase)

ALP is an enzyme associated with the bile ducts and bones. Elevated ALP levels may suggest bile duct obstruction, certain bone conditions, or other underlying factors. In some cases, ALP can be naturally raised during pregnancy or periods of bone growth in younger individuals.

GGT (Gamma-Glutamyl Transferase)

GGT is another enzyme linked to bile duct function. It is particularly sensitive to alcohol consumption and is frequently included in liver panels for this reason. Raised GGT alongside raised ALP may suggest bile duct involvement, whereas an isolated GGT elevation can sometimes be associated with alcohol intake or certain medications.

Bilirubin

Bilirubin is a yellowish substance produced when old red blood cells are broken down. The liver processes bilirubin so it can be excreted from the body. Elevated bilirubin levels may cause visible yellowing of the skin or eyes (jaundice) and can suggest the liver is not processing bilirubin efficiently.

It is worth noting that a mildly raised bilirubin level is sometimes linked to a benign inherited condition called Gilbert's syndrome, which affects a notable proportion of the UK population and is generally considered harmless.

Albumin

Albumin is a protein made by the liver. It plays a key role in maintaining fluid balance in the body and transporting substances through the bloodstream. Low albumin levels may suggest the liver's ability to produce protein has been affected over time and can sometimes be associated with chronic liver conditions, nutritional factors, or kidney-related issues.

Total Protein

This measures the combined level of albumin and globulins in the blood. Abnormal total protein levels — either high or low — may prompt further investigation into liver function, immune function, or nutritional status.

Practical Insight: Mild variations in liver biomarkers are relatively common and do not always indicate a significant health concern. Factors such as recent exercise, medications, supplements, and diet can sometimes influence results.

What Do Abnormal Liver Function Test Results Mean?

Receiving results that fall outside the normal reference range can understandably cause concern. However, it is important to understand that abnormal liver function test results do not automatically mean there is a serious liver condition present. Results may be influenced by a wide range of factors.

Common Reasons Liver Markers May Be Raised

Alcohol consumption — even moderate intake can temporarily affect GGT and ALT

Medications — including over-the-counter painkillers, statins, and certain supplements

Fatty liver changes — increasingly common in the UK, often linked to diet and lifestyle

Viral infections — such as hepatitis A, B, or C

Recent intense physical exercise — which can temporarily raise AST

Herbal supplements — some herbal products may affect liver enzymes

When Results May Suggest Further Investigation

If liver function test results show significantly elevated levels, persistently abnormal results across repeated tests, or a pattern affecting multiple biomarkers simultaneously, it may be appropriate to seek medical advice for further evaluation.

Important: Our clinic provides testing and reporting only. We do not offer diagnosis, treatment, or prescriptions. If your results suggest any areas of concern, we recommend discussing them with an appropriate healthcare professional who can provide personalised medical advice.

Who Should Consider a Liver Function Test?

Liver function testing may be particularly relevant for individuals who:

Consume alcohol regularly or above recommended UK guidelines

Are taking long-term medications that may affect the liver

Have a family history of liver conditions

Are living with metabolic risk factors such as obesity or type 2 diabetes

Have experienced unexplained fatigue, abdominal discomfort, or changes in appetite

Want a baseline health check as part of a proactive wellness approach

Have previously had abnormal liver results and wish to monitor changes over time

Many people across London choose to include liver function testing as part of a broader health screening blood test to build a clearer picture of their overall wellbeing.

Practical Insight: You do not need to have symptoms to consider liver function testing. Many liver-related changes develop gradually and may not produce noticeable symptoms in the early stages, which is why routine screening can be a valuable part of preventive health.

How Often Should You Have a Liver Function Test?

There is no single answer that applies to everyone. The frequency of liver function testing depends on individual circumstances, lifestyle factors, and any existing health considerations.

As a general guide:

Annual testing may be appropriate for individuals who consume alcohol regularly, take long-term medication, or have metabolic risk factors

Every 6 months may be considered for those monitoring previously abnormal results

One-off testing can be helpful for anyone seeking a baseline understanding of their liver health

Your healthcare provider can advise on the most appropriate schedule based on your personal circumstances.

NHS vs Private Liver Function Testing in London

Factor	NHS	Private (e.g., Private Blood Tests London)		---	---	---		Referral required	Typically yes	No referral needed		Waiting time	Can vary, sometimes several weeks	Appointments often available promptly		Result turnaround	Varies by practice	Typically faster turnaround		Walk-in convenience	Generally appointment-based via GP	Flexible booking options		Cost	Free at point of care	Fee applies — [check our website for details](https://www.privatebloodtestslondon.co.uk/)		Follow-up advice	GP provides next steps	Results provided; further advice via your healthcare provider

Both NHS and private routes are valid options. Private liver function testing in London can be a practical choice for individuals who prefer quicker access without a referral, or those who want to include liver markers as part of a wider blood test panel.

Practical Insight: Private testing complements rather than replaces NHS services. If your results highlight areas of concern, sharing them with your registered healthcare provider can support continuity of care.

Frequently Asked Questions About Liver Function Test Results

1. What does a liver function test actually measure?

A liver function test measures a panel of enzymes, proteins, and substances — including ALT, AST, ALP, GGT, bilirubin, and albumin — that reflect different aspects of liver health and bile duct function. Together, these biomarkers can help provide a broad overview of how the liver is performing and whether further medical advice may be appropriate.

2. Can liver function test results be abnormal without liver disease?

Yes, liver function test results can sometimes fall outside normal ranges due to factors unrelated to liver disease. Recent vigorous exercise, certain medications, herbal supplements, temporary viral illness, and even recent alcohol intake may influence enzyme levels. Persistently abnormal results are generally more significant than a single mildly raised reading.

3. Do I need to fast before a liver function blood test?

Fasting is not always required for a standard liver function test, although some clinics may recommend it if the test is being combined with other markers such as cholesterol or glucose. It is advisable to check with your testing provider in advance to receive specific preparation instructions.

4. How quickly will I receive my liver function test results?

At Private Blood Tests London, results are typically available within a short timeframe following your appointment. Turnaround times may vary depending on the specific panel requested. Our team will advise you on expected timescales when you book.

5. What should I do if my liver function test results are abnormal?

If any of your liver function biomarkers fall outside the reference range, we recommend discussing the results with a qualified healthcare professional. They can assess your results alongside your medical history, symptoms, and lifestyle to determine whether further investigation or monitoring may be appropriate.

6. Can I get a liver function test in London without seeing a GP first?

Yes. At our nurse-led clinic in London, you can book a liver function test without needing a GP referral. This makes private blood testing a convenient option for individuals who want proactive access to health screening. Visit our booking page for available appointments.

7. Is a liver function test the same as a liver disease test?

Not exactly. A liver function test measures biomarkers that reflect liver activity and health, but it is not a definitive diagnostic tool for specific liver diseases. Abnormal results may prompt further evaluation by a healthcare professional, which could include additional tests or clinical assessment.

8. Can lifestyle changes improve liver function test results?

In many cases, lifestyle modifications — such as reducing alcohol intake, maintaining a balanced diet, increasing physical activity, and reviewing medications with a healthcare professional — may positively influence liver biomarker levels over time. Repeat testing can help monitor changes.

9. Are liver function tests suitable for young adults?

Liver function testing is not limited to older adults. Young adults who consume alcohol regularly, take certain medications, or have relevant family history may also benefit from having their liver biomarkers checked. Early awareness can support proactive health management.

10. How does Private Blood Tests London ensure quality and accuracy?

Our nurse-led clinic follows rigorous quality standards. Samples are processed by accredited UK laboratories, and our service complies with relevant regulatory standards to ensure reliability and accuracy in reporting.

About This Article — Editorial Standards

This article has been produced by the content team at Private Blood Tests London in accordance with UK medical editorial best practice. All information is intended for educational purposes only and does not constitute medical advice, diagnosis, or treatment.

The content is informed by widely recognised clinical references and is written using evidence-based phrasing to support clear, accessible public health education. Our clinic operates as a nurse-led testing and reporting service and does not provide diagnoses, prescriptions, or treatment.

If you have concerns about your liver health or any blood test results, please consult an appropriate healthcare professional for personalised advice. If you are experiencing severe symptoms such as jaundice, severe abdominal pain, or persistent vomiting, seek urgent medical care immediately.

Take a Proactive Step Towards Understanding Your Health

Knowing what your liver function test results mean is an important part of taking ownership of your wellbeing. Whether you're looking for a baseline check, monitoring existing markers, or simply seeking peace of mind, understanding your blood test results can help you have more informed conversations with your healthcare provider.

If you'd like to arrange a liver function test at our central London clinic, you can explore the options available on our website or book an appointment at a time that suits you. Our friendly, nurse-led team is here to support you every step of the way.

*Private Blood Tests London — Accessible, confidential health screening in the heart of London.*

What Do Liver Function Test Results Mean?