The guideline is designed to be used in both primary and secondary care and includes recommendations on: 3. Although traditionally referred to as liver function tests LFTs , typical testing panels include measurement of hepatobiliary enzymes in addition to true measures of liver function.
For this reason, the BSG guidance refers to liver blood tests rather than LFTs to capture more accurately the relevance to clinical practice. There is no standardised panel for liver blood tests and testing varies between hospitals. Liver blood tests can be a challenge to interpret; results may be normal or near normal even in advanced liver disease, and, when abnormal, the degree of abnormality may not reflect disease severity—liver blood tests may be abnormal even when there is no significant liver disease.
Liver disease can develop with few signs or symptoms, but using liver blood tests to investigate non-specific symptoms that may indicate liver disease, such as anorexia, fatigue, or nausea, may identify a hepatic condition that can be effectively treated. Liver blood tests, including international normalised ratio INR , should be used to assess and monitor liver function in patients who have symptoms or signs of cirrhosis, portal hypertension, or liver failure.
Signs and symptoms include ascites, peripheral oedema, spider naevi, and hepatosplenomegaly. Patients with other autoimmune diseases are known to be at increased risk of developing autoimmune liver disease.
Liver blood tests may, therefore, be appropriate if patients with autoimmune diseases develop symptoms that suggest liver disease, such as pruritus in primary biliary cholangitis. Because a wide variety of drugs have been associated with liver disease, liver blood tests may be recommended to monitor liver function in patients prescribed certain medications such as carbamazepine, methyldopa, minocycline, macrolide antibiotics, nitrofurantoin, statins, sulphonamides, terbinafine, chlorpromazine, and methotrexate.
Although statins can lead to drug-induced liver injury this is rare, and studies have demonstrated that statins are generally suitable for use in patients with pre-existing abnormal liver enzymes. Liver enzymes are of little value in assessing the extent of alcohol misuse, and are a poor guide to the development of progressive fibrosis in alcohol-related liver disease ARLD. Elevated enzymes may, however, be useful in motivating behaviour change, with elevated gamma-glutamyltransferase GGT being the best predictor of mortality.
Chronic viral hepatitis may be associated with non-specific symptoms, including fatigue, but most patients are symptom-free. Risk factors for hepatitis include: 3. Normally suspected following abnormal liver blood tests or an echobright liver on ultrasound scan, non-alcoholic fatty liver disease NAFLD is, in part, a diagnosis of exclusion.
When fatty change is seen on ultrasound, other causes including alcohol misuse and viral hepatitis, should be considered. The BSG guidelines 3 include information on a range of different liver blood tests, providing guidance on how test results should be interpreted and making recommendations for further investigations that may be appropriate. Most laboratories report total bilirubin, which will be raised by an elevation of either the conjugated or the unconjugated form.
Interpretation of hyperbilirubinaemia in neonates and infants requires specialist support because of the risk of kernicterus and the need to diagnose with urgency conditions such as biliary atresia. Albumin is a protein synthesised by the liver that can serve as a marker of synthetic liver function. Albumin concentration may, however, be reduced in other clinical situations, including sepsis, systemic inflammatory disorders, nephrotic syndrome, malabsorption, and gastrointestinal protein loss.
Alkaline phosphatase ALP is predominantly a liver enzyme but is also found in bone and in smaller quantities in the intestines, kidneys, and white blood cells. Levels of ALP are higher in childhood and in pregnancy, where it is associated with bone growth and placental production, respectively.
Raised ALP may also result from cholestasis caused by hepatic congestion due to right-sided heart failure. If ALP is elevated in isolation, measurement of GGT see below can help to provide some indication as to whether or not the origin is hepatic, and, if doubt remains, electrophoresis can be used to differentiate hepatic from non-hepatic ALP.
The liver performs a number of vital bodily functions, such as:. The different liver function tests can also monitor the progression or treatment of a disease and test for the side effects of certain medications. Your doctor will give you complete instructions on how to prepare for the blood sample portion of the test. Certain medications and foods may affect levels of these enzymes and proteins in your blood.
Your doctor may ask you to avoid some types of medications, or they may ask you to avoid eating anything for a period of time before the test. Be sure to continue drinking water prior to the test. You may want to wear a shirt with sleeves that can easily be rolled up to make it easier to collect the blood sample.
You may have your blood drawn in a hospital or at a specialized testing facility. To administer the test:. Blood draws are routine procedures and rarely cause any serious side effects.
However, the risks of giving a blood sample can include:. After the test, you can usually leave and go about your life as usual. However, if you feel faint or lightheaded during the blood draw, you should rest before you leave the testing facility. The results of these tests may not tell your doctor exactly which condition you have or the degree of any liver damage, but they might help your doctor determine the next steps. Your doctor will call you with the results or discuss them with you at a follow-up appointment.
In general, if your results indicate a problem with your liver function, your doctor will review your medications and your past medical history to help determine the cause. Your doctor may decide to test you for hepatitis, other infections, or other diseases that can affect the liver. They may also choose to do imaging, like an ultrasound or CT scan. They may recommend a liver biopsy to evaluate the liver for fibrosis, fatty liver disease, or other liver conditions.
Fatty liver, or hepatic steatosis, is a broad term that describes the buildup of fats in the liver. Too much fat in the liver can cause liver…. Learn about liver cancer symptoms, types, diagnosis, treatment, and prevention. This is because it interferes with your liver function and can cause very serious side effects, even death. If a possible side effect of the medication is liver damage you should make sure to do regular liver function tests.
How diet affects your liver function Your diet has a big impact on the health of your liver. The worst foods for your liver include:. The good news is that it usually takes years for permanent liver damage to develop.
So if you catch it early enough, there are lots of lifestyle changes you can make so that your liver can repair itself. To improve your liver function and long-term health , you should:. Harris, E. Elevated liver function tests in type 2 diabetes. Clinical diabetes, 23 3 , O'shea, R. Alcoholic liver disease. Hepatology, 51 1 , Park, E. Dietary and genetic obesity promote liver inflammation and tumorigenesis by enhancing IL-6 and TNF expression.
Cell, 2 , Smith, B. Non-alcoholic fatty liver disease. Critical reviews in clinical laboratory sciences, 48 3 , Thoma, C. Lifestyle interventions for the treatment of non-alcoholic fatty liver disease in adults: a systematic review.
Journal of hepatology, 56 1 , Understand how your lifestyle impacts your health with a home blood test and GP-reviewed results. Careful interpretation of liver function tests within the clinical context can help elucidate the cause and severity of the underlying pathology. Predominantly raised alkaline phosphatase represents the cholestatic pattern of biliary pathology, whilst predominantly raised alanine aminotransferase and aspartate aminotransferase represent the hepatocellular pattern of hepatocellular pathology.
The severity of liver dysfunction or biliary obstruction is reflected in the bilirubin level and the degree of liver synthetic function can also be indicated by the albumin level.
Beyond the liver function tests, prothrombin time provides another marker of liver synthetic function and a low platelet count suggests portal hypertension. Key words: Liver function test, cholestatic pattern, hepatocellular pattern, liver synthetic function. Derangement of liver function tests LFTs is a common problem that can be difficult to interpret. The clinical context is an important guide, but liver disease can be asymptomatic until the late stages and abnormal blood tests may be the first indication of disease.
LFTs include liver enzymes, albumin and other proteins, and bilirubin. The liver enzymes are produced by cells within the liver. The protein components comprise total protein, albumin and globulin [N.
The globulins are a mixture of globular proteins such as immunoglobulins, enzymes, carrier proteins and complement. Typical normal ranges for LFTs and other blood tests are shown in Table 1, but may vary according to your local laboratory.
Liver enzymes are a poor reflector of liver function, but rather of cholestasis and liver cell integrity, respectively [1]. Liver enzymes have different normal ranges, so assessment of their relative abnormalities by number of times greater than their upper limit of normal ULN can be more informative than the absolute values. In the acute setting, a cholestatic pattern of LFTs is seen with bile stones, when accompanied by colicky right upper quadrant pain or in cholestatic drug-induced liver injury when there is a history of a new causative medication.
A more chronic presentation may be due to pancreatic, liver or bile duct tumours or cholestatic autoimmune liver disease such as primary biliary cholangitis or primary sclerosing cholangitis. ALP is also produced outside the liver by organs such as bone, placenta, kidneys and gut. Hence ALP may be raised in the presence of normal liver health, most commonly due to bone disease or pregnancy.
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