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Flashcards in Clinical Chemistry Deck (113):

What are Reference ranges

normal values
reference ranges established by measuring the laboratory parameters in a group of normal animals


Describe the anatomy of the liver

receives nutrient blood hepatic artery- (20%) blood supply
80%-hepatic portal vein from- stomach, intestines, pancreas, spleen
blood leaves the liver- HEPATIC VEIN --> Caudal VENA CAVA


Describe the portal triad

hepatic a., portal v. --> blood flow toward central v
bile duct--> bile flows in opposite direction


What is the function of the liver

metabolism of fats, carbohydrates, and protein
Stores Glucose as glycogen
Production of albumin and other plasma proteins
Detoxification ( drugs, ammonia)-- urea
Bile Metabolism –excretion of bilirubin
Produces Coagulation Factors


Why would an animal be jaundice if his liver wasn't working

His body cannot reabsorb the bilirubin


Why wound an animal have hypoalbuminemia if his liver wasn't working

Because the liver isn't producing albumin


Why would the animal have problems with hemostasis if his liver wasn't working

The liver isn't producing the clotting factors


Why would the animal have hypoglycemia if his liver wasn't working

There are glucose stores in the liver


Why would the animal have Hyperlipoproteinemia if his liver wasn't working

Due to the lack of metabolism of proteins and fats


Why would the animal have hepatoencephalopathy if his liver wasn't working

Because the ammonia isn't being filtered out


At what point in liver damage does clinical signs occur

Usually liver disease is greatly progressed before clinical signs appear ( 80%)


What are the 3 types of tests used to evaluate the liver for damage

Enzymes released by damaged hepatocytes = leakage enzymes

Enzymes Associated with Cholestasis

Hepatic function tests


What are the Enzymes released by damaged hepatocytes

Alanine Aminotransferase ALT (SGPT)
Aspatate Aminotransferase AST (SGOT)


What tests are used to find enzymes released by damaged hepatocytes

Sorbitol (Iditol) Dehydrogenase SDH
Glutamate Dehydrogenase GLDH


What is Cholestasis

obstruction of flow of bile


What are the enzymes associated with cholestasis

Alkaline Phosphatase ALK

Gamma glutamyl transpeptidase GGT


What are the four hepatocyte function tests

Bile Acids
Dye excretion
Bile Acids


What is the significance of ALT in cats and dogs

In Dogs Cats, primates, hepatocyte is major source  Considered liver specific in these species

It is considered a screening test for liver disease


What can cause a false positive increase in ALT in cats and dogs

There will be a Mild increase  in feline hyperthyroidism + steroid therapy + anticonvulsant tx


What is specific about ALT in horse, ruminant, pig, bird

it is not clinically significant as a marker for liver function


When are elevations seen in ALT

elevations seen w/n 12 hours of liver hepatocyte damage


When do elevations of ALT return to normal

in 2 weeks


Describe the significance of elevated AST in cats and dogs

Enzyme is in the mitochondria thus more severe liver damage required to elevate it

AST also found in muscle tissue- cardiac+ skeletal + RBCs- rise after strenuous exercise, or muscle damage as well as hemolysis will cause an elevation


When do AST levels return to normal

Rise more slowly and return to normal w/n a day (short half life)


How do you distinguish if AST levels are from muscle or liver damage

Increase in AST but normal ALT = muscle damage

CK will rise only with muscle damage


What is CK

Creatinine Kinase is an enzyme that is in muscle tissue, but not in liver. skeletal muscle, and cardiac muscle damage
CK is frequently assayed if an animal has an elevated blood AST level but shows no clinical signs of liver disease


What causes CK elevations

from intramuscular injections,
persistent recumbency, surgery,
vigorous exercise, electric shock, laceration, bruising, and hypothermia. Myositis and other myopathies


When is CK included on a biochem profile

In horses or Cows to screen for liver damage


What is Sorbitol (Iditol) Dehydrogenase

Primarily found in hepatocyte
Shows liver damage in large animals ( ALT NOT USEFUL)
Can be use in all species


What is special about testing Sorbitol Dehydrogenase

Unstable in serum- samples have to be frozen


What is AP/ALK

Found In Liver, osteoblast (BONE)
corticosteroid induces an isoenzyme of AP
Young animals - elevated AP due to - bone development


What is AP/ALK used to determine

Used to detect cholestasis in dog and cat
Will see elevations with cushings b/c of x/s cortisol
Very significant in cat
Not useful in large animals


How do you determine Indirect Bilirubin amount

Usu 2/3 of the Total Bilirubin
see ↑ liver problem


What happens to direct bilirubin in cholestasis

↑ with actual biliary obstruction


What are bile acids

Synthesized in the hepatocyte from cholesterol and glycine or taurine
Secreted in the bile duct for fat digestion
95% actively reabsorbed from the ileum back into the liver


What do you do if you see elevated SBA

—> serum BA are usually very low.
Elevated SBA- screen for liver function


How do you test for elevated bile acids

Need 2 blood samples 1- fasting + 2 hour post prandial


What is a portosystemic shunt

Often congenital
 ductus venosus fails to collapse at birth  this allows blood to bypass or shunt around the liver. 


What are the clinical signs of a portosystemic shunt

clinical signs include "stunted" growth
May have mild microcytic anemia- ammonium biurate crystals and will have increase Bile Acids


What are liver function tests used in research settings

Indocynine Clearance
Ammonia Tolerance
Caffeine Clearance
Bromsulfophthalein Excretion


What is cholesterol

Plasma lipoprotein produced by liver


What are cholesterol levels a screening test for

Screening test for hypothyroidism
T4 controls synthesis and destruction of cholesterol
Also elevations seen with other endocrine diseases


What is elevated cholesterol usually associated with

Elevated CHOL is often associated w Hyperlipemia


What are the functions of the kidneys

Filter waste and other products
Water and electrolyte Balance
Acid-base balance
Activate Vit D
Renin-angiotesin ( blood pressure control)


What is the BUN

Urea is an end product of amino acid metabolism
The more protein in diet- the more urea is formed in the liver


What happens to UREA in the body

All urea passes through the glomerulous – about ½ gets reabsorbed by the renal tubules and ½ will get excreted


In what situations do you see elevated BUN


High protein diet
+strenuous exercise -

Loss of kidney function (75%)


What is creatinine

Formed from creatine from the msl
Remains constant with constant physical activity
Total amount of Creatinine is related to msl mass
All creatinine is filtered through the kidney
None is reabsorbed
Not influenced by a high protein diet


How much of the kidney must be destroyed to see elevated creatinine

Must have >75% kidney destruction to see elevation


What is GFR

Glomerular Filtrate Rate


How is GFR and Creatinine related

Any condition that alters GRF alters creatinine since all is excreted and none is reabsorbed


What does the BUN/Creatinine ratio show

75% kidney destroyed b/f inc in Bun/CREAT

Not that sensitive for early detection of renal dse

GFR has to be decrease 4 fold b/f there is an increase


What is micro albuminuria used for

Can be useful To detect early onset kidney disease


what do you look for in UA for evidence of kidney disease?

Low Spec. Gravity, protein loss


Why is the UPC used to detect early renal disease

Based on the concept that the tubular concentration of urine increases both the urinary protein and creatinine concentrations equally


How do you evaluate UPC

Cystocentesis is preferred method
5- renal dse


What is SDMA

SDMA is a methylated form of the amino acid arginine, which is produced in every cell and released into the body’s circulation during protein degradation. SDMA is excreted almost exclusively by the kidneys, making it a good marker for estimating kidney function


What is uric acid produced

By product of protein metabolism
Transported to kidney by albumin- passes thru the glomerulous and gets reabsorbed by the tubule cell- gets converted to allantoin and then excreted in the urine


Describe the defect of the dalmation

Uric acid is excreted into urine to create urate urolith


In avian and reptile, describe uric acid significance

Uric acid is major end product of nitrogen metabolism

Uric acid is used to measure renal function in Avian and Reptile species


What is Gout

uric acid crystals deposit in joints, tendons, and surrounding tissues and cause inflammation.

Birds and reptiles on a too high of a protein diet or with Kidney disease will get gout


What is a water deprivation test used for

Is done to see if the Kidney can concentrate urine


What are differential diagnoses if you have PUPD

Cushing's dse
Diabetes mellitus
Diabetes insipidus
Psychogenic polydipsia


What is the goal of the water deprivation test

GOAL: Dehydrate the patient safely until endogenous ADH is produced
This happens at 5% body weight loss


What must you monitor if you're doing a water deprivation test

When doing a water deprivation test you must monitor body weight and C.S. of dehydration
Monitor urine specific gravity


When is the water deprivation test contraindicated

Test is contraindicated if animal is already dehydrated or azotemic


What is the vasopressin response test used for

to see if you have Diabetes Insipidus


What are common endocrine pancreas problems

Endocrine --- Diabetes mellitus, insulinoma


What are common exocrine pancreas problems

Excocrine -- EPI- pancreatitis-- cancer


What are the exocrine pancreas function tests

Exocrine Pancreas – Lipase, amylase, trypsin…..


What are the endocrine pancreas function tests

Endocrine Pancreas-- Insulin + glucagon


What happens when there is inflammation of the pancreas

trypsin, amylase, lipase- when there is inflamation these enzymes leak into the serum


What is EPI

Low level enzymes in pancreas


What does EPI cause

MALDIGESTION-- secondary to malabsorption

Causes- Pancreatic Acinar Atrophy (German Shepard)
or loss of pancreatic tissue from chronic pancreatitis


How do you test for trypsin levels

Can test feces for its presence
Test tube method, x-ray film method


Why do you test for trypsin

To rule out pancreatic exocrine insufficiency


What is Serum Trypsinlike immunoreactivity

Radioimmunoassay that uses antibodies to trypsin
Detects both trypsin+trypsinogen
TLI is increased in pancreatitis but not that useful a test for pancreatitis


What is the TLI good for

Specific and sensitive test for pancreatic exocrine insufficiency when decreased


What type of blood sample do you need for TLI

Use fasting blood sample


What is Malabsorption

Nutrients are not being absorbed through the microvilli


What are tests for malabsorption

Tests for Malbsorption
serum Cobalamin + Folate


Why do you test for amylase levels

Amylase: acute/chronic pancreatitis or obstruction of pancreatic duct will result in elevations
If GFR decreased- rise in amylase


What is an insulinoma

Tumor of beta cells- produces hypoglycemia with seizures- common in ferrets


What does increased fructosamine indicate

Increase fructosamine indicates a persistent hyperglycemia


What is the half life of albumin

Half life of albumin is 1-2 weeks
So gives an indication of glucose control over the last 2 weeks


How long do glycosylated Hb last

2-4 months


What hormone lowers blood glucose



What hormones raise blood glucose

glucagon, adrenaline, cortisol, growth hormone


What is type 1 diabetes

insulin dependant diabetes
pancreas is not producing enough insulin usually because of immune destruction of the beta cells


What is type 2 diabetes

Type II diabetes- non insulin dependant diabetes – insulin resistance

cats more common – associated with obesity-(fat cells hide receptors)


What are the predisposing factors to type 2 diabetes

About 1 in 200 animals affected
Obesity esp in cats causes type 2
Middle age
Other hormones-- cortisone, progesterone
More in Neutered male cats or middle age intact bitches


What does insulin do in the body

it allows the cells to use glucose- Even though the blood glucose is high – the cells can not use the glucose- so they breakdown fat and use protein from the lean body mass


What are the clinical signs of diabetes

Polyphagia, PUPD, weight loss
Cataracts (dogs)
Polyneuropathy, Plantigrade posture(cats)
Prone to bacterial infections


How do you diagnose diabetes

Fructosasmine elevated ( 2-4 weeks)
Glycosylated hemaglobin increased (2-4 months)


What si the goal of treatment of the diabetic

Stabilize– glucose levels-
Insulin injection

Minimize post prandial hyperglycemia
Provide optimum amount of nutrients
Minimize clinical signs (PUPD, neuropathy…
Avoid hypoglycemia- fatal


What are the 3 steps to dietary treatment of diabetes

1-Consistent amounts, consistent timing, consistent ingredients, consistent proportion of CHO, protein, fat -- fixed ingredient profile

2-Slow absorption of glucose from intestine
Low in simple sugars, High in Complex carbohydrates—barley, sorghum- to slow glucose absorption( low in simple sugars)

3-Fiber- some slow gastrointestinal transit time- hemicellulose, carboxymethylcellulose
Fibers slows absorption of nutrients – ie glucose


Describe nutrition goals of a diabetic

Protein- good quantity and quality- to protect lean body mass– also will provide amino acids for gluconeogenesis

Antioxidants– Vit E

FAT content will depend on BCS


What are the important macros for diabetic animals

For Dog Diet
60% CHO
20% Protein
20% FAT



What nutraceuticals should you give if an animal is diabetic

Chromium- potentiate insulin

Carnithine – help with fat metabolism



When is a glucose curve done after an animal is diagnosed with diabetic

Glucose curve is usually done 4-6 weeks post start of injections


How do you perform a glucose curve

Hospitalize the animal ( can train owners to do at home)
Follow the pet owner’s normal regime. This includes insulin injections, size, type and timing of meals and exercise routine. – ALSO good to watch Owner give the Insulin
Take a blood sample prior to insulin injection.
Feed the animal ( 1/3 daily ration). Administer the insulin
Take a blood sample every two (to four) hours, if possible for 24 hours but at least until the concentration has crossed back above the renal threshold.
Blood glucose concentrations are measured and plotted against time to produce a blood glucose curve.


What is the aim of treatment of diabetes mellitus

You want blood glucose concentrations to be below the renal threshold and to avoid hypoglycemia
Thus the goal is to maintain blood glucose concentrations roughly between:

5 and 10-12 mmol/l (90 and 180-216 mg/dl) in dogs
5 and14-16 mmol/l (90 and 252-288 mg/dl) in cats


How do you measure the duration of insulin action

The duration of insulin action is measured from the time of insulin injection, followed by a fall in blood glucose concentration, to the time that blood glucose exceeds the renal threshold.


How is once daily caninsulin treatment to be considered effective in dogs

For once daily Caninsulin treatment to be considered effective in dogs the duration of the insulin action needs to be at least 20 hours.


How is twice daily caninsulin treatment to be considered effective in dogs

For twice daily Caninsulin treatment to be considered effective, the duration of the insulin action has to be around 8-12 hours following each insulin injection.


What is the ideal blood glucose curve

Normal blood glucose in non-diabetic cats ranges from 2.6 - 8.4 mmol/l.
The renal threshold is 14mmol/l.
The goal is produce a blood glucose curve that approaches the reference range but avoids potentially fatal hypoglycaemia, for example 5 - 14 mmol/l for most of each 24 hour period.


What is the Somogyi effect

An insulin dose that is too high may bring about the Somogyi effect or rebound hyperglycaemia.
This can also be produced if blood glucose concentrations fall too rapidly. The moment that the Somogyi effect is triggered is very individual – it is a life-saving response.


What do long-acting insulins do

Long-acting insulins and insulin analogs
Ultralente insulins - 100% crystalline insulin
PZI insulins - contain protamine and zinc
Insulin glargine is an insulin analog that is released slowly over a period of up to 24 hours (in humans) and intended to supply a basal level of insulin.


What are intermediate acting insulins

Lente insulins (e.g. Caninsulin) - mixtures of 30% amorphous (semilente) and 70% crystalline (ultralente) insulin in an aqueous suspension.
NPH insulins - contain protamine


What are rapid acting insulins

Soluble insulin and semilente insulin: intravenous administration possible
Insulin lispro, insulin aspart and insulin glulisine are insulin analogs that readily absorbed from the injection site which are used to provide a bolus of insulin for after a meal (in humans)


What is 40 IU mean

40 units per ml


How do you do an insulin tolerance test

Give .1IU/kg regular- short acting insulin
Insulin resistance if BSL fails to drop50% of the pre fasting level
Insulin receptors are unresponsive to insulin


How do you treat hypoglycemia

Always be ready to tx hypoglycemia – with IV glucose