AST/ALT

ALAT (alanine aminotransferase), formerly called GPT (glutamic pyruvic transaminase),
ASAT (aspartate aminotransferase), formerly called GOT (glutamic oxaloacetic transaminase),
are the most important enzymes of the aminotransferase group or transaminases that catalyze the transfer of amino units, α-keto acids to amino acids.
This test is used to diagnose liver diseases and to report the progress of hepatitis disease treatment.
It is also used in necrotic cirrhosis diseases and the delayed effects of drug therapy.
ALAT is also used to differentiate between hemolytic jaundice and jaundice caused by liver diseases.
ALAT, as a specific enzyme of the liver, increases only in liver patients, but in the level of ASAT,
as it increases in liver parenchymal damage, cardiac or muscle percentage also increases.
Simultaneous measurement of ASAT and ALAT is used to detect cardiac and muscle damage from liver damage
The ASAT/ALAT ratio is used in the differential diagnosis of liver diseases. If the ASAT/ALAT value is less than one,
it indicates mild liver damage, and if the value is greater than one, it indicates severe damage or chronic liver disease.

ALK-P

ALK-P is an enzyme that optimum activity is in alkaline pH and its value is considered as a tumor marker or indicator of liver and bone diseases.
ALK-P can be seen in blood in different forms and is found in large amounts in liver and bone,
but it is also present in other tissues such as kidney, placenta, intestinal wall, thymus gland, lung and testis.
Physiologically, alkaline phosphatase increases in growing children and during pregnancy, and pathologically in bone and liver lesions.
It is also used in bile duct obstruction, cholestasis, obstructive jaundice, liver cysts and abscesses,
hepatitis infections, bone diseases and cases where osteoblast activity is high, such as Paget's disease, Rickets,
Osteomalacia and hyperparathyroidism, the amount of ALK-P increased.

Bilirubins 

Bilirubin is a yellow bile pigment that is produced by the natural breakdown of hemoglobin. Free unconjugated bilirubin is highly nonpolar and insoluble in water.
Therefore, it forms a complex with albumin for transport from the spleen to the pancreas through the blood.
In the liver, bilirubin is conjugated to glucuronic acid and converted to bilirubin glucuronic acid and excreted in a water-soluble form through the bile ducts.
Increased bilirubin is observed as a result of increased production due to hemolysis (prehepatic jaundice),
liver parenchymal damage (interhepatic jaundice), and bile duct obstruction (posthepatic jaundice). Also, chronic
and hereditary increase in bilirubin is called Gilbert's syndrome, which is relatively common.
In 60 to 70 percent of newborns, bilirubin levels increase due to the destruction of red blood cells
and the delay in the function of enzymes in the breakdown of the resulting bilirubin.
Common methods of measuring bilirubin show the amount of total bilirubin and direct bilirubin,
where direct bilirubin is actually a measurement of the amount of conjugated and water-soluble bilirubin.
The amount of unconjugated bilirubin can be determined from the difference between the amount of total and direct bilirubin.
Bilirubin metabolism disorders are associated with serious complications, especially in newborns.
In a 70-kg person under physiological conditions, about 6 grams of hemoglobin are destroyed and resynthesized daily.