Clinical biochemistry lab BIOC 416 2013 Liver Function profile LFT Enzymes Liver Liver is an important organ in human body Synthesis of proteins glycogen storage drug metabolism and detoxification process ID: 934041
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Slide1
Khadija BalubaidKAU-Faculty of Science- Biochemistry department Clinical biochemistry lab (BIOC 416)2013
Liver Function profile (LFT)Enzymes
Slide2Liver Liver is an important organ in human body Synthesis of proteins, glycogen storage, drug metabolism and detoxification processMany diseases can affect liver functions as:
Viruses (heptites A,B,C,D,G)
Cirrhosis Inflammation JaundiceFatty liver
Slide3Slide4Slide5Liver profile Profile : is group of tests specific for one organ Liver function tests (LFTs or LFs), are groups of clinical biochemistry laboratory
blood (serum or plasma) or urine assays designed to give information about the state of a patient's liver
These tests can be used to detect the presence of liver disease
distinguish
among different types of liver disorders
Gauge
the extent of known liver damage,
follow
the response to treatment.
Slide6Slide7SGPT (Serum Glutamate Pyruvate Transaminase) Liver enzymes
Produced by liver cells.
ALT found primarily in liver.Normal : 7 – 41 U/LUpto 300U/L – nonspecific , any type of liver disorder(CLD…cirrhosis /malignancy)>1000U/L – extensive hepatocellular damage ( viral hepatitis, ischemic liver injury , toxin /drug induced liver injury )
ALT (alanine amino
transferase
) or
Slide8High serum ALT due to: Liver cells damage due to inflammation, virus infection or cell death (why?) when liver cells damaged ALT enzyme leaks to blood stream leads to rise its level in serum. Some medication may also elevate serum ALT, because some drugs cause liver damage leads to rise ALT level.
ALT is the most sensitive marker for liver cell damage;
since it is only synthesized by liver cells other enzymes may be also synthesized by other organs.
Slide9Less sensitive that ALTSynthesized by : liver, cardiac muscle, skeletal muscles, kidneys, brain, pancreas, lungs,
leucocytes and RBC Normal – 12 – 38U/L
AST – liver , cardiac muscles, skeletal muscle, kidneys, brain, pancreas, lungs, leucocytes, RBC in decreasing order.2 Iso enzymes- cytoplasmic, mitochondrialMild degree of tissue injury – cytoplasmic form in serum
Severe injury – mitochondrial type in serum
AST (
Aspartate
amino
transferase
)
or
SGOT (Serum Glutamate
Oxaloacetate
Transaminase
)
Slide10High serum AST due to: Muscle damage, myocardial infarction (heart attack) and in chronic liver disease. To confirm that high AST is due to heart or muscle injury; other enzyme (creatinine kinase CK) which is specific for heart, is also tested.
Because it is less sensitive the ration ALT/AST is calculated ALT
: < 35U/L, AST: <40U/L elevated ALT,AST : acute hepatitis (viral or toxic ), chronic hepatitis and cirrhosis,biliary obstruction
Slide11ALP (alkaline phosphatase)It is related to bile duct.ALP
normal level: 30-130 U/L It is not specific for bile
because it is synthesized also by bone and placenta (isoenzymes)High serum ALP may be due to: bile duct
damage
(inflammation, cirrhosis or obstruction)
In alcohol hepatitis
.
Hepatocellular carcinoma
Normal physiological elevation :During pregnancy During child growth
To assess the etiology of ALP elevation, GGT and bilirubin levels are also measured.
Slide13Used in body for syn of glutathione11 iso enzymesNormal : 9 – 58
U/LProduced by liver, kidney and
pancreas, intestinal cells,and prostateElevated in: toxins, alcoholism,obstructive
Jaundice,and
neoplasm of liver
Slightly high normally in males
prostate
To
detect alcohol abuse
Rised
even when other LFT are normal in
alcohalics
.
GGT falls rapidly within few days after abstinence
.
Used To
confirm hepatic etiology of ALP elevation
GGT (Gamma
Glutamic
Transpeptidase
)
Slide14General indications Conformational procedures Indications Enzymes Serology (for virus)Biopsy, ultrasound (liver size)Hepatitis. may be due to ( virus, medication, toxin)
ALTAST/ALT ratio, CK to confirm heart disease Not specific.
May be due to ( muscle disease, heart disease, liver disease) ASTGGT to confirm liver Gallbladder ultrasound Bile problems (stone or bilary duct obstruction) Liver disease Normal physiological elevation ( child, pregnancy)
ALP
Liver toxin, alcohol,
cirohsis
GGT
In general, every enzyme can gives you specific indication:
Slide15Experiment:Measuring serum AST levelPrinciple: The rate of NADH oxidation is directly related to AST activity which measured photometrically. L-aspartate +
a oxoglutarate L-glutamate +
oxaloacetateOxaloacetate + NADH + H+
L-
malate
+ NAD
+
MDH
AST
Slide16Notes:Samples: Unhemolyzed serum or plasma collected in heparin or EDTA tube.(why?)
Stability of AST in serum: 2 days at 20-25o
C or 4 days at 2-8oC
Slide17Kit components Reagent 1: mixture of: buffer (pH 7.5) +
substrate (L-aspartate)
Reagent 2: mixture of: enzyme (MDH) + coenzyme (NADH)
Slide18Procedure Prepare working reagent: by mixing reagent 1 and 2 together Zero adjust the spectrophotometer with air or dis. H2O
Prepare the reaction as the following:
Mix After 30 sec. read the absorbance at 340nm. (R1) Repeat the reading after 1min and 2 min (R2, R3)
Calculate the mean absorbance
mean = R1+R2+R3/ 3 or (R2-R1)+(R3-R2)/2
Sample tube
1 ml
Working reagent
100
m
l
Sample (serum)
Slide19Calculations:25oC
18 U/L Men
15 U/L Women
AST catalytic conc. U/L = mean A X factor
* factor = 1946
Reference value “ normal rang”:
Slide20Interfering factors Therapeutic heparin increase ASTHemolysed blood increase ASTMany drugs falsely increase or decrease AST