Introduction and Chemical Pathology Lab

Question 1

What is ESR and how does it change in infection?

Answer 1

Erythrocyte Sedimentation Rate – the rate at which red blood cells settle out of suspension in blood plasma, measured under standard conditions

ESR increases in infection

Question 2

What is likely to accompany infection and how does this occur?

Answer 2

FEVER: then infection is a likely cause

Fever is caused by the immune system rather than the organism

Hence it can occur in autoimmune 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 red blood cells – this is used for measuring blood glucose because live red blood cells will consume the glucose

Question 6

Which bottle is used for measuring HbA1c and why?

Answer 6

Purple Top – potassium EDTA.

If glucose sticks to the haemoglobin it becomes a bit heavier and its movement slows down oWhen you perform the electrophoresis, you’ll find that in a patient with poorly controlled diabetes, there will be more HbA1coAs the red cells survive for roughly 3 months, this measure tells you how good the blood glucose control has been over the previous 3 months

Question 7

What is serum and what is it useful for measuring?

Answer 7

When blood clots and you remove the clot you are left with serum

Serum contains electrolytes but NO clotting factors

• If there is no anticoagulant in the tube, the blood will clot
• When it clots, all the clotting factors are used up so when you remove the clot you are left with serum
• Serum contains NO CLOTTING FACTORS
• Serum is useful for measuring electrolytes

Question 8

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

Answer 8

The gel stimulates clotting

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 potassium so haemolysis caused by poor collection will result in an increased serum potassium concentration

Question 10

Describe the anticoagulants that can be used and what this does?

Answer 10

• EDTA or heparin
• Clotting factors unused
• Blood can be separated into red cells and plasma
• If you put any anticoagulant into the tube the blood wont clot and will remain as a liquid and the clotting factors wont be used up
• The clotting factors in the plasma are inhibited by EDTA and heparin

Question 11

When do you need to contact a chemical pathologist?

Answer 11

• When you want the sample to be rapidly centrifuged out of hours
• When you want to measure labile hormonessuch as insulin•When you urgently need CSF glucose and protein to be measured
• Meningitis -­‐if there is bacteria then they will consume the glucose

Question 12

What does the blue top mean?

Answer 12

Contains citrate

It is reversible and used to measure clotting factors

Citrate binds to calcium and prevents clotting When you get a sample of blood in a citrate bottle, you add just the right amount of calcium to trigger the clotting cascade

Question 13

What is this used to measure?

Answer 13

PT and APTT, measure clotting time

Question 14

What is creatinine a marker of and what is GFR?

Answer 14

Creatinine is produced in muscle and is produced constantly oMuscle mass normally stays roughly the same through adult life so the amount of creatinine that you produce stays the same

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

Question 15

What is urea a marker of?

Answer 15

Dehydration

It is also excreted by the kidneys

urea levels vary a little bit depending on your diet (urea comes from protein)

Question 16

How do these two markers change in renal disease?

Answer 16

They increase

When you are dehydrated, the kidneys start reabsorbing more water and accidentally absorbs some urea

Question 17

What are the three main liver enzymes?

Answer 17

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

Question 18

How does albumin change in liver disease?

Answer 18

Albumin levels fall in liver disease

Question 19

What other cells, other than hepatocytes, contain alkaline phosphatase?

Answer 19

Osteoblasts

Question 20

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

Answer 20

After a fracture – osteoblasts use ALP to build more bone.

your ALP will RISEbecause the bones are building and the osteoblasts secrete ALP while they make bone

Question 21

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

Answer 21

ECG

Question 22

What is measured to confirm a heart attack?

Answer 22

Measure troponin levels

If you suspect a heart attack, you check troponin-­‐if it is raised then it is a heart attack

Question 23

List the main cardiac enzymes.

Answer 23

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

Question 24

What else could cause heart attack type symptoms?

Answer 24

A bleeding peptic ulcer

Question 25

what can be present when seeing someone with lviefr failure?

Answer 25

jaundice

Total Bilirubin (excreted in the faeces through the bile) oIf there is something wrong with the liver or the biliary tree then bilewill leak into the blood so you get high bilirubin •Also, if the liver fails, liver albuminwill begin to fall