Introduction and Chemical Pathology Lab

Question 1

What is ESR and how does it change in infection?

Answer 1

Erythrocyte Sedimentation Rate
= rate at which RBCs settle out of suspension in blood plasma, measured under standard conditions
ESR increases in infection

Question 2

Fever is normally a sign of infection. How is it possible for some autoimmune conditions to cause fever?

Answer 2

Fever is caused by the immune system rather than the organism
Hence it can occur in AI disease in the absence of an organism

Question 3

What are the four tube colours for blood collection and what do the colours mean?

Answer 3

Red: no anticoagulant
Yellow: gel, makes the coagulation occur faster
Purple: potassium EDTA
Grey: fluoride oxalate

Question 4

What are the purple cap bottles used for?

Answer 4

Potassium EDTA keeps the cells alive

It is used when measuring cell counts or anything in general to do with the cells

Question 5

What are the grey cap bottles used for?

Answer 5

Fluoride oxalate kills the RBC’s – this is used for measuring blood glucose because live RBC’S consume glucose (anaerobic glycolysis)

Question 6

Which bottle is used for measuring HbA1c + FBC?

Answer 6

Purple Top: potassium EDTA

Question 7

What is serum and what is it useful for measuring?

Answer 7

When blood clots + clots are removed = serum

Serum contains electrolytes but NO clotting factors

Question 8

How is gel designed so that it separates serum from the rest of the blood?

Answer 8

It is more dense than serum but less dense than cells so it separates the serum from the cells

Question 9

What can skew the electrolyte measurements of the serum?

Answer 9

Haemolysis: red cells contain a lot of K+ so haemolysis caused by poor collection will result in an increased serum K+ concentration

Question 10

What does the blue top mean?

Answer 10

Contains citrate
It is reversible + used to measure clotting factors
Citrate binds to Ca2+ + prevents clotting
Add sample of blood to citrate bottle, + just the right amount of Ca2+ to trigger the clotting cascade

Question 11

What is the blue top bottle used to measure?

Answer 11

PT

APTT

Question 12

What is creatinine a marker of?

Answer 12

Renal function (GFR): produced by body at a constant rate + is excreted at a constant rate provided that the kidneys are functioning normally

Question 13

What is raised urea a marker of?

Answer 13

Dehydration

Excreted by the kidneys

Question 14

How do creatinine + urea change in renal disease?

Answer 14

They increase

Question 15

What are the 3 main liver enzymes?

Answer 15

Alanine aminotransferase (ALT) 
Aspartate aminotransferase (AST) 
Alkaline phosphatase (ALP)

Question 16

How does albumin change in liver disease?

Answer 16

Albumin levels fall in liver disease

Question 17

What cells, other than hepatocytes, contain alkaline phosphatase?

Answer 17

Osteoblasts

Question 18

Other than liver disease, when else might ALP be high?

Answer 18

After a fracture – osteoblasts use ALP to build more bone

Question 19

What is the first thing you do if a patient presents with heart attack type symptoms?

Answer 19

ECG

Question 20

What is measured to confirm a heart attack?

Answer 20

Troponin levels

Question 21

List the 4 main cardiac enzymes.

Answer 21

Troponins  
Creatine Kinase (CK) 
Aspartate aminotransferase (AST) 
Lactate dehydrogenase (LDH)

Question 22

When does a chemical pathologist need to be contacted?

Answer 22

When need sample to be rapidly centrifuged out of hours
When need to measure a labile hormone e.g. Insulin
When urgently need CSF glucose + proteins to be measured

Question 23

What is investigated when investigating liver function?

Answer 23

AST

GGT

Question 24

What does the “liver” box of the checklist measure?

Answer 24

Albumin
Bilirubin
Alkaline Phosphatase
ALT