Liver function

Liver function tests (LFTs)

A liver panel assesses how the liver is working. Functions of the liver include:

  • Separating nutrients from waste.
  • Detoxifying and purifying blood.
  • Producing bile (for digesting fat and removing waste), cholesterol, clotting factors, globin (a colourless protein that carries oxygen in the red blood cells), and immune factors that protect against infection.  
  • Absorbing fats and vitamins, including A, D, E, and K.
  • Metabolising and distributing the nutrients from foods (fats, proteins, and carbohydrates).
  • Storing energy in the forms of glycogen, vitamins, and minerals (including iron reserves).
  • Excreting bilirubin, cholesterol, hormones, drugs, and bile.

Toxins, viruses, and cancer can all damage liver function. Cirrhosis is an irreversible, chronic condition that scars normal liver architecture, interfering with blood flow through the liver and leading to the liver’s inability to perform its biochemical functions. Alcoholic hepatitis causes serious liver damage, but is sometimes reversible. When the liver is not working properly, the body's ability to produce protein is reduced, energy levels fall, and the blood may not be properly cleaned. 

Liver function is commonly monitored among people taking antiretroviral therapy because of the risk of liver dysfunction from toxicity. Nevirapine and efavirenz are two drugs that require careful monitoring, particularly in the first months of therapy.

Liver function tests (LFTs) include alanine aminotransferase (ALT/SGPT), alkaline phosphatase (ALP), aspartate aminotransferase (AST/SGOT), total bilirubin, direct bilirubin, albumin, ammonia, and total protein, among others. All of these tests can be done with a blood sample obtained from a vein in the arm. 

Liver biopsy

A liver biopsy may be needed if X-ray, ultrasound, or computed tomography scan (CT, CAT) do not provide enough information about a liver problem. There are three procedural options for doing a liver biopsy: percutaneous, laparoscopic, and transvenous.

For a percutaneous liver biopsy, a local anaesthetic is given to numb the area and a needle is inserted through an incision into the right side to retrieve the tissue sample. An ultrasound image may be used to guide insertion. There may be a sensation of pressure and dull pain during the procedure, which will take about 20 minutes.

A laparoscopic biopsy involves placing a tube (the laparoscope) through an abdominal incision. The laparoscope sends images to a monitor that is used by the physician to guide removal of tissue samples.

A transvenous biopsy is done by inserting a catheter (tube) into a vein in the neck and guiding it to the liver. A needle then goes into the catheter to remove the tissue sample from the liver. This technique is usually employed when the patient may have blood clotting problems or abdominal fluid.

Fasting is usually required for eight to ten hours before the procedure. Liver biopsy is considered minor surgery, so it is usually done at a hospital on an outpatient basis. Afterwards, the patient needs to lie still for one to two hours before leaving for home. The next eight to 12 hours should be spent in bed. It takes about a week for the incision and liver to heal and physical exertion should be avoided during that time. 

Hepatitis testing

Hepatitis is a general term indicating inflammation of the liver. It can be diagnosed with a blood test that detects either specific viral antigens and/or antiviral antibodies.

Hepatitis A (HAV or Hep A) is diagnosed with a blood test that detects immunoglobulin M anti-HAV presence. A person is protected from future Hep A infection by antibodies, but will always test positive for the virus. 

Hepatitis B (HBV) is diagnosed with a blood test that detects the presence of hepatitis B surface antigen (HBsAg) and IgM antibody to hepatitis B core antigen (anti-HBc IgM). Antibodies in the body have a number of variations that indicate past vaccination or immune globulin receipt, past or present infection, recent infection, active viral replication and infectivity, and acute or chronic HBV.

Hepatitis C (HCV) is determined with a blood test that detects HCV antibodies. If a person’s first test is positive, the result needs to be confirmed and liver enzymes should be measured. Antibodies to HCV may not show up in the blood for five to 12 months. HCV-RNA and RT-PCR are two testing methods that can determine HCV infection in one to two weeks. 

Hepatitis D (HDV) occurs only in someone who also has hepatitis B. A blood test will detect anti-HDV in someone who is ‘super-infected’ with both HBV and HDV. 

Hepatitis E (HEV) is diagnosed by blood tests that detect elevated antibody levels of specific antibodies to hepatitis E in the body or by RT-PCR. HEV has also been identified in the stool of patients with acute HEV infection through use of immune electron microscopy. 

Hepatitis G (HGV, GBV-C) can be detected by anti-E2 ELISA (envelope protein-2 antibodies), RT-PCR, or real-time PCR. Hepatitis D occurs only in someone who also has hepatitis C.  

Hepatitis F (HFV) was originally identified in stool samples; however, the actual existence of the virus is not yet verified and remains dubious.

How they will help

Elevated ALT is an early warning of liver damage. Physical symptoms of liver stress are hepatomegaly (enlarged liver) or jaundice (yellowing of the skin and eyes). Raised levels of ALT are indicative of obstruction in the bile ducts or infections such as TB or MAI.

Discovery of co-infection with hepatitis C will influence prescribing and timing of drugs to treat both HIV and HCV.

If a drug is identified as causing liver problems, the dose may be reduced or the drug may be switched out for another less toxic.

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.