1: Intro and Chemical Pathology Flashcards
What is a Liver Function test? (LFT)
List the markers
Testing for markers that are in the bloodstream. Amount of markers INCREASE with liver damage.
AST, ALT, GGT
Albumin = produced by liver, marker of liver health
Any sepsis can make LFT abnormal
List the urea & electrolyte markers that can be tested
Urea
Creatinine
Na+
K+
What is ESR?
Erythrocyte sedimentation rate
It is a marker of chronic inflammation
What types of stool culture are there?
Microscopy - can tell you if its parasitic or bacterial
Culture (takes longer to develop)
Sensitivity - tells you which antibiotic to use
What are the different blood test tubes?
RED top = NO anticoag
YELLOW top = gel to speed up clot
PURPLE top = Potassium EDTA
GREY top = Fluoride oxalate (poison)
What is the purpose of Potassium EDTA in purple tops?
Potassium EDTA keeps the cells alive
So if you want to do anything with cells you need purple top
What is the purpose of fluoride oxalate?
KILLS red blood cells
Used if you want to measure blood glucose
(RBCs consume glucose so will give inaccurate reading)
What colour test tube do you use for each test?
U&E = serum in yellow/red top Glucose = plasma in grey top HbA1c = plasma in purple top TFT = serum in yellow/red top LFT = yellow/red top
What is HbA1c?
Glycated Hb
Form of Hb that is covalently bound to glucose
What is the difference between serum and plasma?
Serum has NO coag factors
Useful for measuring electrolytes
Red top has no anticoagulant so blood will clot and use up all the coag factors - then you are left with just serum
Why would you want to use anti-coagulant in test tubes?
Name the anti-coags used
If you want to separate blood into RBCs + plasma
Blood wont clot and will remain as a liquid. Clotting factors wont be used up
Use EDTA or heparin
If red cells haemolyse during blood collection, what would you see after centrifuging the sample?
PINK plasma
Because cells are full of potassium, and there would be extra potassium in the plasma due to haemolysis
High potassium level = fucked
What is the BLUE top container?
Contains citrate, an anticoagulant (binds to calcium)
Useful as it is reversible
It is used to measure clotting factors
When sample is given in citrate bottle, you add a shot of calcium to START the clotting process (i.e. reverse the anticoag effect)
Then you can measure PT/APTT
When do you contact a chemical pathologist?
- When you want the sample to be rapidly centrifuged out of hours
- When you want to measure labile hormones (insulin)
- When you urgently need CSF glucose and protein to be measured (e.g. in meningitis, bacteria would consume CSF glucose)
What is creatinine? What does it indicate?
Creatinine = marker of GFR (kidney function)
Normal creatinine = normal kidney function
Its produced CONSTANTLY in muscle
Muscle mass is roughly the same throughout adulthood so rate of creatinine production is FIXED.
Creatinine is NEVER reabsorbed
What is urea? What does it indicate?
Urea = marker of dehydration
When dehydrated, kidneys reabsorb some urea along with water
Urea levels = High if dehydrated, but GFR stays the same til the end
What are the typical U&E results for Addison’s disease?
Low Na+
High K+
High urea
Normal creatinine
What are common markers tested in LFT?
ALT = Alanine Aminotransferase AST = Aspartate Aminotransferase ALP = Alkaline Phosphatase These can leak into blood if liver is damaged HIGH liver enzyme levels = LIVER DAMAGE
ALP is also used by osteoblasts in bone growth. You can measure liver/bone specific ALP
After FRACTURE -> ALP will rise (osteoblasts secrete ALP)
HIGH Total Bilirubin = Liver/biliary tree damage
If something’s wrong with liver/biliary tree, bile will LEAK into blood -> HIGH total bilirubin
Albumin - synthesised in the liver
LOW albumin = LIVER DAMAGE
In a patient with jaundice what other liver markers would you need to measure?
AST and GGT
List the cardiac enzymes
Troponins
Creatine Kinase
AST
Lactate Dehydrogenase (LDH)
Normally found in cardiac tissue, should NOT be present in blood
If patient presents with chest pain + tightness, what tests should you do next?
- ECG to see if they’re having an acute heart attack
- If you suspect heart attack, check cardiac enzymes
RAISED TROPONIN = HEART ATTACK
Heart attack symptoms also caused by PEPTIC ULCERS
Careful not to give thrombolytics to someone with bleeding ulcers
