Liver Function Tests in Context to Veterinary Practice

Gives you detailed insights into LFTs of various animals

1. Presentation of
Veterinary Lab Diagnosis on
Liver Function Tests (LFTs)
Prepared
by:
Harshit
Saxena

2. Clinical Biochemistry-Biochemical diagnosis
Diagnostic Clinical Biochemistry uses biochemical knowledge
and techniques to
A). diagnose a disease
B). Follow its progress
C). Monitor effect of treatment
As these directly manifest the metabolic process inside body
of a organism they give more real insight to a clinician to
better understand his subject

4. What are Liver Function Tests???
•Liver function tests(LFTsorLFs), also referred to as a
hepatic panel, are groups of blood tests that provide
information about the state of a patient'sliver
•LFT is rather a misnomer:
As all LFTs don’t refelect or measure functionality of liver
but also includes Cellular damage, Underlying disease,
Cholestatic/Biliary disorders acting as MARKERS
•Only the bilirubin and albumin given in this panel offer
information regarding the functional capacity of the liver
•No single test is enough to access the functional states-
‘Battery of tests’ or ‘set of tests are used

6. Indications
•Screening : They are a non-invasive yet sensitive screening
modality for liver dysfunction
•Pattern of disease : They are helpful to recognize the pattern
of liver disease. Hepatic or biliary; Type of jaundice
•Assess severity : They are helpful to assess the severity and
predict the outcome of certain diseases like primary biliary
cirrhosis.
•Follow up : They are helpful in the follow up of certain liver
diseases and also helpful in evaluating response to therapy like
autoimmune hepatitis.
•Tests should be correlated to other data & clinicalinformation

7. Classification
On the basis of component measured:
1.Excretory rate of parentrallyadministered
substances such as BSP
2.Ability of the liver to remove substances from the
serum and detoxify them
3.Serum levels of liver enzymes that increase following
hepatic injury
4.Indirect assessment of hepatic function such as
blood glucose, serum proteins, clotting factors and
urinalysis

8. Bilirubin Test

9. Some facts about Bilirubin
•Bilirubinis a yellow compound that occurs in the
normalcatabolicpathway that breaks downhemeinvertebrates.
•This catabolism is a necessary process in the body's clearance
of waste products that arise from the destruction of aged or
abnormalred blood cells
•First thehemoglobingets stripped of the hememolecule which
thereafter passes through various processes
ofporphyrincatabolism
•The production ofbiliverdinfrom hemeis the first major step in
the catabolic pathway, after which theenzymebiliverdin
reductaseperforms the second step, producing bilirubin from
biliverdin
•This unconjugated bilirubin produced bind to albumin proteins
and called as Indirect Bilirubin or Unconjugated Bilirubin

10. Bilirubin Metabolism

11. Direct & Indirect Bilirubin

13. 4.

18. IctericIndex
•Analysed by comparing colour of Azobilirubin formed with
Pottasium dichromate
•Help in judging degree of Icterus(Jaundice)
•Icteric Index:
Species Icterus Index
Dog 5.8-6
Cattle 8.4-9.8
Sheep 6.8-10.7
Buffalo 7.1-9.8
Horse 15.2-18
Prothrobin time
•Time required for clotting of blood Taken as criteria to evaluate status
of Liver, since prothrombin is synthesized in liver
•Capillary tube method used. In
Hepatic fibrosis this increases to
15-17 sec
Specie Normal CT
Cattle 7 min
Horse 11 min
Dog and Cat 2-3 min
Sheep & Infront 2 min

19. Total serum protein & Albumin:Globulin Ratio
1.Normal A:G
a. Hyperproteinemia: Dehydration
b. Hypoproteinemia: Overhydration, Acute blood/plasma loss
2.Decreased A:G
a.DecreasedAlbumin: Liver disease, Glomerulonephritis, Internal
parasites
b.Increasedglobulin-Acute & Chronic ID, Neoplastic syndrome, Polyclonal
& Monoclonal gammopathies tumours if RE system
3.Increased A:G
a.IncreasedAlbumin: Does’ntoccur except in dehydration
b.DecreasedGlobulin: Serum of foetus & precolostral neonate,
immunodeficiency, Aglobinemia

20. Serum lipids & lipoprotein
•Estimation of cholesterol, Ratio of Esterified to Unesterified Cholesterol may
help in diagnosing hepatic diseases
•In acute hepatic damage cause increase of triglycerides, decrease in
cholesterol esters & abnormal lipoprotein pattern in serum
•Changes may be due to low lecithin, cholesterol, acetyl transferase &
triglyceride lipase . Normal cholesterol levels are: mg/dL
Cattle 65-220, Sheep-43-103, Swine-28-48, Horses-46-180
Serum Uric Acid
•In dogs estimation of serum uric acid is useful in detecting liver
diseases
•Other animals-Not much important
•Purine metabolized to uric acid which is converted to Allantoin in liver
through Uricase enzyme
•Hepatocellular damage :Conversion of Uric Acid to allantoin is reduced
& Uric Acid is accumulatedin circulation leading to up of 10 times rise in
serum uric acid level in such cases

21. Serum Bile Acids
•Very sensitive and specific parameter to diagnose hepatic
condition in Bovines & also in Canines with Portosystemic shunts
•Bile acids are formed due to metabolism of cholesterol in liver &
excreted in bile
•Reabsorbed from intestine either unchanged or after microbial
transformation
•Rise of them is proportional to degree of hepatic damage
•Elimination of IV administered radiolabelled bile salts can be
method to determine their amount

22. Iodine Test
•Reagent: Iodine crystals 1mg
Pottasium Iodide 2mg
Distilled Water 27ml
Keep the reagent in amber coloured bottle
•Place a drop of serum on glass & put one drop of reagent with
needle
•Flocculation produced in liver damage
•Grading on the basis of flocculation (+), (++), (+++)
•Read test for routine purpose fibrosis of cattle & aflatoxicosis

23. Takata-ara test
•8 test tubes with 1ml NS is taken in each tube serial
dilutions were made as 1in2, 1in4, 1in16, 1in64,
1in128,1in256 & so on
•Now add 0.25 ml of 10% Sodium bicarb.+0.15 ml of 0.5%
mercuric bichloride & mi
•Reaction read in half hour after 24 hours at room
temperature
•Positive reaction-Dense flocculation
•Atleast first 3 test tubes should show agglutination
•Detect liver damage and cirrhosis

24. 2.Serum Enzyme Tests
•There are mainly two types of Serum enzymes
1.Organ specific-Present mainly in liver called liver specific
2. Organ Nonspecific-Present in liver as well as other
organs/tissues of the body
•These are either stored in cytoplasm of cell (Ex: Transferases)
or in the mitochondria (Ex: Dehydrogenases)
•Damage to the cells of any organ due to tissue insult result in
the release of these enzymes into the circulation
•To determine that wheatherthese Enzymes belong to liver as
result of hepatic insult or not involvement of other organs
must be ruled out.

25. Normal level of enzymes in different animals
Enzymes CattleHorse Goat Sheep Pig Dog Cat
AST 20-34 58-9443-132 79±118.2-21.66.2±136.7-11
ALT 4-11 1-6.7 7-24 11±1 9-174.8±241.7-14
Alkaline
Phosphatase
0-38 11-31 7-30 5-30 9-31 3-16 2-7
Glutamine
Dehydrogenase
0-1.8
Lactic
dehydrogenase
176-36541-10431-99 60-11136-16010-3516-69
Ornithine
Carbamyl
transferase
4.75±0.33.3±4.2 7±.073.8±1.0
Sorbitol
Dehydrogenase
4.3-15.31.9-5.814-23.65.8-27.91-5.81.0-5.83.9-7.7
Source: Keneko,JJ(1974) Standard values in domestic animals.
Univ. Calif. Davis

26. Aspartate amino transferase (AST) &
Alanine amino transferase (ALT)
•AST –Also k/as Serum glutamic oxaloacetate transaminase (S.G.O.T.)
•ALT-Also k/as Serum glutamic pyruvic transaminase (S.G.P.T.)
•Localised in high concentrations in cytoplasm of hepatocytes
•Following hepatic injury or necrosis, these enzymes are leaked from
ruptured cell membrane as it become more permeable
•Also produced by cells surrounding the necrotic area as to compensate
the level of damage
•ALT is liver specific in canines not in ruminants & other animals
•AST is non liver specific also secreted by muscles both smooth and
cardiac, heart, kidneys, pancreas & intestine

28. Conditions for Elevation of ALT & AST
Elevation of ALT :
1.Hepatic necrosis
2.Hepatoxin
3.Fatty liver
4.Drug induced(steroid
estrogen, chloramphenicol,
gentamycin, erythromycin,
dilantin, salicylates
5.Diseases-Diabetes mellitus,
hypothyroidism,
leptospirosis, ICH, Feline
infectious peritonitis
Elevation of AST:
1.Downer cow syndrome in
cattle &buffalo
2.Fatty cow syndrome
3.Ketosis in cattle
4.Pregnancy toxaemiain ewe
5.Azoturiain equines
6.Acute liver damage in farm
animals
7.White muscle disease
8.Extensive use of drugs like
steroids, salicylates,
estrogen,
erythromycin,lincomycin,
gentamycin

29. Diagnostic algorithm for the children with elevated AST
and ALT

30. Serum Alkaline Phosphatase (S.A.P.)
•Found in several tissues of the body.Present as 3
isoenzymes in liver intestine & placenta
•Normal values:
•Liver donot clear but catabolizes and this SAP is of primary
liver origin
•It is found on the edges of cells that form bileducts, tiny
tubes that drain bile from the liver to the bowels where it
is needed to digest fats
•Elevated levels found when there is hepatic problem and
especially in bile duct obstructionis present
•Rise in SAP level depends on the site of lesion
A. In periphery : cause severe obstruction of bile flow and
thereby marked increase of SAP
B. In centrilobular area: slight elevation in SAP activity

31. Serum Arginase
•It is a liver specific enzyme bound to mitochondria and has short
half life in blood
•Useful for Acute hepatic disease but for chronic disease it is of
little value
•Severe damage cause release of this enzyme as mild insult is not
able to harm mitochondria storehouse of arginase
•Prognostic importance in conjunction with ALT, where activity of
both enzymes increases simultaneously
•In regeneration phase activity of arginase come to normal

32. Lactic dehydrogenase(LDH), Sorbitol
dehydrogenase (SD) & Glutamate
dehydrogenase (GD)
•Liver specific enzymes bound to mitochondria and
increases when liver damage occur
•Selectively for Acute liver damage
•LDH got two major sites liver and cardiac muscle in liver
its present in mitochondria and severe acute insult cause
its level to rise
LDH Elevation:
Hepatic damage
Muscle damage
Renal damage
Myocardial damage
Pancreatic damage
Haemolysis
SDH Elevation:
Hepatic damage
Aflatoxicoses
Pancreatitis
Obstructive jaundice
Azoturia in a horse
Prolonged steroid
therapy
GLDH Elevation:
Hepatic tissue
damage(liver specific)

33. Gamma-Glutamyl transferase(GGT)
•Present in liver and kidneys of ofmost of animals but in horses
also present in pancreas
•Higher activity of GGT in serum is due to liver enzyme and its
higher activity in urine suggest kidney damage involved in both
acute and chronic hepatic damage
•Has greater half life in serum
•Its activity increase in hepatocellular damage, hepatic
necrosis,bileductobstruction
Ornithine carbamyltransferase(GGT)
•Liver specific enzyme for ruminants
•Involved in Urea cycle
•Elevated in both acute and chronic damage if active liver necrosis
occur

35. 3.Dye Excretion/Clearance Test
•Uptake and Excretion of organic dyes like Suphobromophthalein(BSP),
Rose Bengal & Indocyanine green(ICG)can be measured to evaluate
both hepatic function & hepatic blood flow
•These dyes are taken by liver, conjugated & excreted
•Delayed removal of the dye from blood may be due to hepatic necrosis
and fibrosis with reduced parenchymatous mass & subsequent
depressed blood flow
•In cases where serum bilirubin level becomes more than 5mg/dl
interpretation become difficult since bilirubin competes with these dyes
for hepatic uptake

36. •Time required to excrete organic dyes and its retention increases
in hepatic damage
•In hypoalbuminaemicanimals most of BSP is unwound&
available for excretion in any given time-here interpretation of
result is difficult
•ICG fraction of clearance ranges from 5.5-9.8%/mint. It has
advantage of over BSP that it helps in measuring blood flow also
•RB dye is primarily removed by liver & excreted into bile in
unconjugated form. But RB dye is of less use in domestic animals

37. 4.Other tests recommended in Veterinary practices
A. Glucose tolerance test: It can measure the ability of liver
to remove glucose from blood.
Dogs-Useful , Ruminants-Not applicable
B. Galactose tolerance test: Measuement of ability of liver to
remove galactose from blood
Significant delay in removal of galactose-Hepatic damage in
Cattle
C. Amino Acid Tolerance: Based on rate of removal of
injected amino acids (tyrosine, arginine)
Increased concentration of AA in blood & urine indicates
hepatic failure
Concentration of cysteine in plasma and urine increases in
infectious hepatitis

38. Recent Advancements in
Liver function tests

39. 1). 99mTc-galactosyl serum albumin
•Technetium-99m–labeledgalactosyl-humanserum albumin(
99m
Tc-
GSA) is a radiopharmaceutical that specifically binds to
asialoglycoprotein receptors on viable hepatocytes, and the
uptakeof
99m
Tc-GSA reflects the functioning hepatocyte mass only
•Posthepatectomy liver failure (PHLF) is one of the most serious
complications after hepatectomy.
•Potential diagnostic ability of
99m
Tc-galactosyl human serum
albumin (GSA) scintigraphy to predict PHLF as defined by the
International Study Group of Liver Surgery (ISGLS).

40. 2). PREALBUMIN
•The serum prealbumin level is 0.2-0.3 g/L. these levels fall in liver disease
presumably due to reduced synthesis
•Because of its short half life, changes may precede alteration in serum
albumin
•Determination of prealbumin has been considered particularly useful in
drug-induced hepatotoxicity.
•Normal plasma levels are 0.2-0.4g/L. Synthesized in the liver and is an acute phase
protein
•The concentration rise in infections, rheumatoid arthiritis, pregnancy, non Wilson
liver disease and obstructive jaundice
•This is an important diagnostic markerin Wilson disease, in which the plasma level
is usually low
•Low levels may also be seen in neonates, Menke’s disease, kwashiorkor, marasmus,
protein losing enteropathy, copper deficiency and aceruloplasminemia.
3). Serum Ceruloplasmin

41. 4. α 1 ANTITRYPSIN
•It is a glycoprotein synthesized by the liver and is an inhibitor of serine proteinases,
especially elastase
•Its normal concentration is 1-1.6g/L. it is an acute phase protein, serum levels
increase with inflammatory disorders, pregnancy and after oral contraceptive pills
(OCP).
•The various alleles coded are M,F,S,Z and null forms. PiZZhomozygotes are
associated with neonatal hepatitis
•. Liver disease is usually seen with deficiency of α 1 antitrypsin, an inherited
disorder
5. α FETO PROTEIN
•This protein, the principal one in fetalplasma in early gestation is subsequently
present at very low levels
•It is increased in hepatocellular carcinoma (HCC)and more than 90% of such
patients have raised levels
•Raised values are also found in other liver diseases like chronic hepatitis, in
regeneration phase of acute hepatitis and in hepatic metastasis

42. Conclusion
In conjunction to Bilirubin Test, Dye reductions, And biomolecular estimation