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)
Blue top= citrate (anticoagulant)

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 top tube, the gel 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 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

Why is citrate useful as an anticoagulant?

Answer 11

It is reversible

Question 12

What is citrate used to measure?

Answer 12

Clotting factors

Question 13

How does citrate act as an anticoagulant?

Answer 13

It binds to calcium and prevents clotting

Question 14

How do you measure clotting factors once you have a sample in the citrate bottle?

Answer 14

You add just the right amount of calcium to start the clotting process then measure the clotting time- PT and APTT- there is a fixed amount of calcium so you need to put the right amount of blood into the tube

Question 15

When do you need to contact a chemical pathologist?

Answer 15

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 16

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

Answer 16

Adrenal failure

Question 17

What is the link between urea and creatinine?

Answer 17

The kidneys excrete both

Question 18

Where is creatinine produced?

Answer 18

In the muscle and produced constantly

Question 19

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

Answer 19

Your muscle mass normally roughly stays the same

Question 20

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

Answer 20

How well your kidneys are functioning- marker of GFR

Question 21

How much do urea levels vary?

Answer 21

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

Question 22

What is urea a marker of?

Answer 22

How dehydrated you are

Question 23

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

Answer 23

You start reabsorbing more water and accidentally absorb some urea

Question 24

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

Answer 24

Dehydrated with normal kidney function

Question 25

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

Answer 25

Both will rise

Question 26

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

Answer 26

High potassium
Low sodium
High urea
Normal creatine

Question 27

Where are liver enzyme found?

Answer 27

In the liver within hepatocytes

Tiny amount leaks into blood

Question 28

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

Answer 28

More leak into the blood

Question 29

What common enzymes are measured in liver function tests?

Answer 29

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

Question 30

What is TBil?

Answer 30

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

Question 31

What happens when the liver fails in terms of albumin?

Answer 31

Liver albumin will fall

Question 32

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

Answer 32

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

Question 33

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

Answer 33

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

Question 34

If you suspect a heart attack, what enzyme do you check?

Answer 34

Troponin

Question 35

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

Answer 35

Troponin
Creatinine kinase
Aspartate aminotransferase
Lactate dehydrogenase