Liver Function Tests (LFTs). Prepared by Hamad ALAssaf a [email protected] Routine Liver Function Tests (LFTs) . LFTs are blood tests used to diagnose & monitor disease or damage of the liver: 1- Serum Albumin 2- Blood Liver Enzymes: - Alanine amino transferase (ALT)
LFTs are blood tests used to diagnose & monitor disease or damage of the liver:
1- Serum Albumin
2- Blood Liver Enzymes:
- Alanine amino transferase (ALT)
- Aspartate amino transferase (AST)
- Gamma glutamyl transferase (GGT)
- Alkaline phosphatase (ALP)
3- Blood Billirubin (total, direct & indirect)
4- Blood Coagulation Factors (prothrombin): Prothrombin Time (PT)
5- Markers of liver fibrosis
Accordingly, no more than traces of albumin may normally appear in urine that can not be detected by ordinary laboratory means.
(ALT & AST)
Aspartate transaminase (AST)
Therefore, blood clotting tests may be used as a marker of the severity of certain liver disorders
With production of
Small amount excreted in urine
1- Liver diseases: are common causes in adults
i- Acute causes: viral hepatitis, ischemia, hepatotoxins
ii- Chronic causes: liver cirrhosis due to alcoholism, hepatitis, biliary obstruction.
2 - GatrointestinalBleeding:
By action of bacteria of GIT on blood urea with production of much amounts of ammonia that is absorbed to blood.
3- Ornithine transcarbamoylasedeficiency (Hereditary)
blood urea levels are elevated
Transfer of urea to intestine is increased
Much amounts of Ammonia is formed by bacterial urease
Absorbed to blood
Breakdown of RBCs
Bilirubin(red-orange) bile pigments
In Blood with albumin
UNCONJUGATED BILIRUBIN (or INDIRECT BILITUBIN)
Bilirubin dissociates from its carrier albumin & enters hepatocytes
In hepatocytes, bilirubin is conjugated with two molecules of
glucuronic acid by the enzyme glucuronyltransferase
Conjugated bilirubin (Direct bilirubin) is transported into bile canalculi
& then into bile.
in the intestine
1- Hemolytic Jaundice: Massive lysis of RBCs in hemolytic anemia e.g. sickle cell anemia & G6PD deficiency anemia & Hemolytic transfusion reaction.
2- Obstructive Jaundice: Conjugated bilirubin is prevented from passing to the intestine. As in Gallstones.
3- Hepatocellular Jaundice: Liver damage (by hepatitis or cirrhosis) causes low conjugation efficiency leading to increased unconjugated (indirect) bilirubin in blood.
Bilirubin accumulates as the liver enzyme bilirubin glucuronyltransferase
(responsible for conjugation of bilirubin) is low at birth. (The enzymes
reaches adult levels in about 4 weeks).
Bilirubin is elevated in blood due to inherited defects in the bilirubin metabolic pathway
2- Gilbert`s syndrome
3- Dubin-Johnson syndrome