Introduction and chemical pathology lab

Question 1

What are the different tubes for collecting blood and what do they contain?

Answer 1

Red top= no anticoagulant
Yellow top= have gel to speed up clot
Purple top= have potassium EDTA
Grey top= have fluoride oxalate (poison)

Question 2

What does the potassium EDTA do?

Answer 2

It keeps the cells alive- what you want if you want to do anything with the cells (red, white and platelets)

Question 3

What does fluoride oxalate do and when is it used?

Answer 3

It is a type of poison that kills the red blood cells, it is used if you want to measure blood glucose- if cells are alive they will consume glucose

Question 4

What is HbA1c?

Answer 4

Glycated haemoglobin

Question 5

What would you expect to find in terms of HbA1c when performing electrophoresis on the blood of someone with poorly controlled diabetes?

Answer 5

More HbA1c which will be found at bottom

Question 6

For what period of time does the electrophoresis show you how good blood glucose control has been?

Answer 6

3 months because that’s how long red blood cells survive

Question 7

What is the difference between serum and plasma?

Answer 7

Serum contains no clotting factors

Question 8

What is serum useful for measuring?

Answer 8

Electrolytes

Question 9

How would you get just the serum from the blood?

Answer 9

Add it to a yellow/red top tube, the gel (w yellow) will speed up coagulation and use up all the clotting factors, the serum and cells are then separated by centrifuge because the cells are more dense than the gel and the gel is more dense than the serum so it separates the two, you can then use a tube to just suck out clot to leave the serum

Question 10

What is a problem with poor blood collection?

Answer 10

Cells are full of potassium
If you do a poor collection and pull hard on syringe you will lyse cells and there will be extra potassium in the plasma which will affect results- you can notice it because it looks pink

Question 11

When do you need to contact a chemical pathologist?

Answer 11

When you want a sample to be rapidly centrifuged out of hours
When you want to measure labile hormones such as insulin
When you urgently need CSF glucose and protein to be measured
Meningitis- if there is bacteria they will consume glucose

Question 12

If someones results contained low sodium and high potassium what would you consider?

Answer 12

Adrenal failure

Question 13

What is the link between urea and creatinine?

Answer 13

The kidneys excrete both

Question 14

Where is creatinine produced?

Answer 14

In the muscle and produced constantly

Question 15

Why does the amount of creatinine that you produce stay the same through adult life?

Answer 15

Your muscle mass normally roughly stays the same

Question 16

As the creatinine production rate is fixed, what does the level of creatinine in the blood show you?

Answer 16

How well your kidneys are functioning- marker of GFR

Question 17

How much do urea levels vary?

Answer 17

A little bit depending on your diet- it comes from protein

Question 18

What is urea a marker of?

Answer 18

How dehydrated you are

Question 19

What happens in the kidney when you are dehydrated in terms of urea?

Answer 19

You start reabsorbing more water and accidentally absorb some urea

Question 20

If someone had high urea and normal creatine, what would you suspect?

Answer 20

Dehydrated with normal kidney function

Question 21

What will happen to urea and creatine levels in renal disease?

Answer 21

Both will rise

Question 22

What will your potassium, sodium, urea and creatine levels be like in addison’s disease?

Answer 22

High potassium
Low sodium
High urea
Normal creatine

Question 23

Where are liver enzyme found?

Answer 23

In the liver within hepatocytes

Tiny amount leaks into blood

Question 24

In terms of liver enzymes, what happens during liver disease?

Answer 24

More leak into the blood

Question 25

What common enzymes are measured in liver function tests?

Answer 25

Alanine Aminotransferase (ALT)
Aspartate Aminotransferase/Transaminase (AST)
Alkaline phosphate (ALP)

Question 26

What is TBil?

Answer 26

Total bilirubin (excreted in the faeces through bile) (increases with liver failure or biliary tree problems)

Question 27

What happens when the liver fails in terms of albumin?

Answer 27

Liver albumin will fall

Question 28

What do you need to measure if a patient has jaundice?

Answer 28

Liver:
- Albumin
-Bilirubin
-Alkaline phosphatase
-ALT
AST
GGT

Question 29

What is the first thing you do when you have a patient presenting with heart attack type symptoms?

Answer 29

ECG to see if they’re having an acute heart attack

Question 30

If you suspect a heart attack, what enzyme do you check to have leaked as muscle is damaged ?

Answer 30

Troponin

Question 31

What other cardiac enzymes are there which will be elevated when there is damage to the heart muscle?

Answer 31

Troponin
Creatinine kinase
Aspartate aminotransferase
Lactate dehydrogenase

Question 32

How to separate rbc and plasma in blood

Answer 32

EDTA or heparin

clotting factors unused