Some tests are associated with functionality (e.g., albumin), some with cellular integrity (e.g., transaminase), and some with conditions linked to the biliary tract (gamma-glutamyl transferase and alkaline phosphatase).
[6] Although example reference ranges are given, these will vary depending on method of analysis used at the administering laboratory, as well as age, gender, ethnicity, and potentially unrelated health factors.
Unconjugated bilirubin is a breakdown product of heme (a part of hemoglobin in red blood cells).
The liver is responsible for clearing the blood of unconjugated bilirubin, by 'conjugating' it (modified to make it water-soluble) through an enzyme named UDP-glucuronyl-transferase.
Overproduction can be due to the reabsorption of a haematoma and ineffective erythropoiesis leading to increased red blood cell destruction.
In one of the studies, measured ALT levels in pregnancy-related conditions such as hyperemesis gravidarum was 103.5 IU/L, pre-eclampsia was 115, HELLP syndrome was 149.
Another study also shows that caffeine consumption can reduce the risk of ALT elevation in those who consume alcohol, overweight people, impaired glucose metabolism, and viral hepatitis.
It is found in highest concentration in the liver, followed by heart, muscle, kidney, brain, pancreas, and lungs.
[10] This wide range of AST containing organs makes it a relatively less specific indicator of liver damage compared to ALT.
An increase of mitochondrial AST in bloods is highly suggestive of tissue necrosis in myocardial infarction and chronic liver disease.
[citation needed] In certain pregnancy related conditions such as hyperemesis gravidarum, AST can reach as high as 73 IU/L, 66 IU/L in pre-eclampsia, and 81 IU/L in HELLP syndrome.
It can also be found on the mucosal epithelium of the small intestine, proximal convoluted tubule of the kidneys, bone, liver, and placenta.
In contrast, low levels of ALP is found in hypothyroidism, pernicious anemia, zinc deficiency, and hypophosphatasia.
[11] In contrast to ALP, levels of ALT, AST, GGT, and lactate dehydrogenase are only slightly changed or largely unchanged during pregnancy.
[6] GGT is a microsomal enzyme found in hepatocytes, biliary epithelial cells, renal tubules, pancreas, and intestines.
Other causes of elevated GGT are: diabetes mellitus, acute pancreatitis, myocardial infarction, anorexia nervosa, Guillain–Barré syndrome, hyperthyroidism, obesity and myotonic dystrophy.
The consequence of low albumin can be edema since the intravascular oncotic pressure becomes lower than the extravascular space.
5' Nucleotidase (5NT) is a glycoprotein found throughout the body, in the cytoplasmic membrane, catalyzing the conversion to inorganic phosphates from nucleoside-5-phosphate.
Its level is increased in infections, rheumatoid arthritis, pregnancy, non-Wilson liver disease and obstructive jaundice.
In Wilson disease, the ceruloplasmin level is depressed which lead to copper accumulation in body tissues.
AFP concentration of more than 400 μg/L is associated with greater tumour size, involvement of both lobes of liver, portal vein invasion and a lower median survival rate.
In liver disease the synthesis of both are decreased and some patients are even found to be hypercoagulable (increased tendency to clot) despite an elevated INR.
In liver patients, coagulation is better determined by more modern tests such as thromboelastogram (TEG) or thomboelastrometry (ROTEM).
They are used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage, and vitamin K status.