LFT (Liver Function Test)

Alanine Aminotransferase (ALT)

The normal ALT levels range from 0-35 U/L.

Lower ALT levels indicate a healthy liver; however, lower levels can also be seen in patients with malnutrition.

A mild to moderate increase in ALT levels is seen in patients with alcoholic liver disease, cirrhosis, chronic liver disease, bile duct obstruction, liver trauma, or any physical injury, or patients taking certain medicines that are harmful to the liver.

A high increase in ALT levels is seen in patients with acute hepatitis like viral hepatitis (Hepatitis A, Hepatitis B, Hepatitis C) or in patients who have taken very high doses of some medicines like paracetamol.

Aspartate Aminotransferase (AST)

The normal AST test results range from 0-35 U/L.

Lower levels of AST in the blood are considered normal, although very low levels are seen in cases of alcoholic liver disease and malnutrition.

High levels of AST are seen in patients with alcoholic liver disease (AST often increases much more than ALT), cirrhosis, chronic liver disease, bile duct obstruction, liver trauma, non-alcoholic fatty liver disease (NAFLD), viral hepatitis (Hepatitis A, Hepatitis B, Hepatitis C) and in patients taking medicines that are harmful to the liver or taking very high doses of some medicines like paracetamol. High levels of AST are also seen in patients with heart attack and muscle injury (however, ALT levels are normal in these patients). A high level of AST with normal levels of ALT indicates that the source of AST is not the liver.

Alkaline phosphatase (ALP)

The normal level of ALP in the blood is 13-100 μ/L

High levels of ALP are seen in patients with bile duct obstruction, hepatitis, cirrhosis, and in liver cancer.

High levels of ALP are also seen in growing children and pregnant women and are considered normal.

Low levels of ALP are seen in patients with malnutrition and certain genetic disorders. ALP levels also decrease temporarily after heart surgery and blood transfusion.

Total Serum Protein

The normal level of Total protein in blood is 5.5-8.0 g/dL.

Albumin & Globulin

The normal level of Albumin is 3.5-5.5 g/dL, approximately 50-60%, and that of Globulin is 2.0-3.5 g/dL, approximately 40-50%. a normal A/G ratio of slightly over 1.

Albumin: Low levels indicate that you may suffer from a disorder where the protein isn't synthesized, digested, or absorbed properly. Lower levels are seen in patients with chronic liver diseases such as cirrhosis, inflammatory liver diseases like hepatitis, and hepatocellular necrosis. Higher levels are seen in liver infections like Hepatitis A, Hepatitis B, and Hepatitis C. High levels may also be seen if you are having a protein-rich diet or if you are dehydrated.

Globulin: Low levels are seen in patients with malnutrition. High levels are seen in chronic active hepatitis and alcoholic hepatitis. It is also increased in acute infection and chronic inflammatory diseases.

A/G Ratio: A low A/G ratio is indicative of overproduction of globulin and reduced production of albumin, which occurs with liver cirrhosis. A high A/G ratio often suggests the decreased production of globulins and is seen in some genetic diseases or leukemia.

Bilirubin

The normal level of Total Bilirubin in the blood is 0.3-1.0mg/dL.

The normal level of conjugated bilirubin (direct) is 0.1-0.3mg/dL.

The normal level of unconjugated bilirubin (indirect) is  0.2-0.7mg/dL.

The lower levels are usually not a concern.

Unconjugated Bilirubin: Higher levels of unconjugated bilirubin are seen in patients with jaundice, acute hepatocellular damage, cirrhosis, viral hepatitis, alcoholic liver disease, bile duct obstruction, liver failure, and in conditions involving an unusual amount of RBC destruction (hemolysis). Increased levels are also commonly seen in newborns, typically 1 to 3 days old. If the bilirubin levels do not return to normal and are increasing rapidly, this may indicate neonatal jaundice.

Higher unconjugated bilirubin levels compared to conjugated bilirubin are suggestive of transfusion reactions and cirrhosis.

Conjugated bilirubin: Higher levels of conjugated bilirubin are seen in patients with hepatitis, gallstones, or inflammation of the bile duct (the duct that carries bile from the liver to the gut).

Gamma-glutamyltransferase (GGT)

The normal level of GGT in the blood is 9-48 U/L.

High levels of GGT are seen in patients with obstructive liver disease, acute and chronic viral hepatitis, cirrhosis, fatty liver disease, cholestasis, alcoholic liver disease, and liver tumors, and in case the patient is taking medicines like phenobarbitone, phenytoin, paracetamol and antidepressants. The low levels of GGT in the blood indicate the absence of liver disease and confirm no alcohol consumption.

There are other conditions as well in which high GGT levels are seen as heart failure, pancreatitis, or diabetes. GGT levels are measured along with ALP. If both enzymes are elevated, it indicates liver disease. If GGT is normal and ALP is elevated, it indicates an underlying bone disease.

Note: Your doctor will interpret your results depending on your gender, age, medications/treatment, or diet you are taking.