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Flashcards in Intro to Biochem Deck (50):
1

List 5 clinical pathology tests

Hematology (CBC)
Clotting profile
Biochemistry
Urinalysis
Cytology

2

What is biochemistry used for?

Evaluate different organ systems
Measure enzymes, metabolites etc.
Use with urinalysis and CBC

3

What fraction of blood is evaluated for buichemistry?

Serum (lacking clotting factors but means nothing is added to tube) vs. plasma which would have clotting factors (inc fibrinogen)

4

When may plasma be used?

Heparinized plasma used for reptiles and birds due to small sample size

5

What colour are serum tubes?

Red or brown

6

What additional chemicals may be added to serum tubes

Serum separator separates cells from serum to prevent RBCs metabolising glucose etc. affecting serum levels

7

What is another term for serum?

Supernatent

8

How should serum be stored?

4 degrees c

9

How is plasma collected?

Into EDTA, Heparin or citrate tubes
Separate plasma from cells by centrifuge
Store at 4 deg C

10

What does within reference interval (WRI) mean?

95% animals will be within the range when healthy
If multiple parameters assessed ^ chance of finding an out of range result.

11

What are blood levels of analytes dependent on?

Amount produced and amount excreted.
Remember if ^ production and concurrent ^ excretion, values will appear within normal range

12

Where is total protein measured from?

Serum or plasma

13

Which value of total protein will be higher (serum v plasma)?

Plasma greater as includes fibrinogen

14

What does total protein consist of?

Albumin and globulins

15

How may total protein be measured? How does this mean results may be affected?

Refractometer (in clinic) or colorimeter (in lab)
Results may be falsely raised by icterus, hemolysis and lipemia

16

When may increased total protein be seen?

Dehydration
Inflammation
Neoplasia

17

When may decreased total protein be seen?

Loss (nephropathy or enteropathy)
Decreased synthesis
Dilution

18

How is albumin measured? In which species is this unrelable and how is this overcome?

Dye binding method
Unreliable in birds - use electrophoresis instead

19

When is increased albumin seen?

Dehydration

20

When is decreased albumin seen?

Loss (renal, hemorrhage, GI)
v synthesis (liver)
3rd spacing (effusions)

21

How is globulin concentration calculated?

Total protein - albumen
(Globulins = all remaining proteins)

22

How would individual globulins be separated and what may this show?

Electrophoresis
If polyclonal shows inflamation (eg. FIP)
If monoclonal shows neoplasia (eg. plasma cell tumour)

23

What 3 things are evaluated when looking at the liver?

Enzymes
Metabolites
Function tests

24

What 2 enzymes, detectable in the blood, does the pancreas secrete most of? Are they pancreas specific?

Amylase and lipase
Not pancreas specific - can come from other sources

25

When are increases in amylase and lipase seen?

Renal insufficiency
Pancreatitis - 4/5 fold increase in dogs, NOT cats

26

Which two analyses must be carried out to evaluate urinary system function?

Serum/plasma chemistry and urine

27

What are urea and creatinine indicators of? What else may they be associated with?

Glomerular filtration
Urea produced by liver so reflects liver function too
Creatinine produced in muscle breakdown (recumbency and IM injections can ^)

28

What is azotemia and what are the possible causes?

^ urea and creatinine in circulation
Causes
- pre-renal: dehydration
- renal: renal disease
- post renal: obstruction

29

How may the cause of azotemia be diagnosed?

Check urine specific gravity - measure of kidneys ability to concentrate urine
If USG low, renal funciton is impaired
If USG normal, dehydration is the cause

30

If urea and creatinine are increased in the serum/plasma, what should USG be in horse, cat and horse/ruminant?

1.030 dog (1.010 would indicate imparied renal function)
1.035 cat
1.025 horse/ruminant

31

In which species is urea not a reliable indicator of renal disease? Why?

Ruminants - use creatinine only
Urea can be excreted into saliva and digested by rumenal microbes, so blood levels may be normal despite impaired renal function

32

What are urea levels influenced by?

Protein intake - high protein meal OR GI bleeding

33

What is the main ion in the ECF?

Sodium

34

What regulates sodium levels? Which other substance follows this?

Kidney
Water balance intrinsically linked

35

How may hypernatraemia occour? Hypo?

Hyper-
^ intake Na
^ water loss
v water intake
Hypo -
^ loss
^ water intake

36

In what paradoxical situations may sodium levels be unuseful in analysing biochemistry of the body?

Na levels always relative to water
SO
HypERnatraemia can result from LOSS of Na IF loss of water is GREATER
Hyponatreamia can result from NORMAL Na levels with increased water intake
etc.
*Na only ion that behaves in this way*

37

Where is the majority of potassium found? What will affect K+ levels?

Intracellular space
Acid/base balance (Inorganic acidosis -> H+ secretion to cells -> K+ ejected into blood stream to balance charges; alkalosis due to H+ loss draws H+ from cells -> K+ taken up by cells to balance charges; Alkalosis due to K+ loss -> H+ taken into cells out of blood stream), intake and renal function all affect levels

38

What does increased K+ indicate?

Renal failure
Hypoadrenocorticism
Muscle/tissue damage allowing leakage eg. leukaemia, rhadomyolysis

39

What does decreased K+ indicate?

Loss (renal/VD) or decreased intake

40

Must shift of parameters always be outside of references ranges to be abnormal?

No, relative to previous concentrations ie. if start extremely low and progress to normal, have actually increased massively

41

What do changes in Cl- usually coincide with?

Changes in Na

42

When are changes in Cl- without changes in Na+ seen?

Acid base balance issues
Vomiting/abomasal displacment

43

What may affect recorded levels of Cl-?

Other halides (test is non-specific)
eg. if treating seizures with Bromide

44

Why is total calcium usually measured? Which fraction of calcium is actually relevant?

Its cheap!
Free calcium is the active form

45

What is calcium bound to? How can this be accounted for when total calcium levels are interpretted?

Albumin
If albumen decreased, bound Ca levels will be decreased and vice versa. So if total calcium high with low albumen, majority of Ca will be free.
Always look at Ca levels in conjunction with albumen
(NB. if increased then would further test free calcium to confirm)

46

What are caclium levels regulated by?

PTH and calcitonin

47

Which other ion is regulated by PTH and calcitonin?

Phosphorus

48

What are increases in phosphorus usually associated with?

Renal disease
Young animals (growing) along with elevated Calcium and ALP
*reference ranges are for adult animals*

49

How may renal damage be compensated for? What does this mean for path diagnostics?

PTH ^ can compensate Phosporus, Vit D and Calcium levels until complete renal failure is imminent

50

What is assessed in a urinalysis?

Gross appearance
Chemical analysis - SG, Urine strip
Sediment analysis - Cells, crystals, casts