Chemical Diagnostics Flashcards
Explain how and when a liver test is performed?
In yellow/red tube
–> measures liver enzymes in blood stream which are elevated in liver disease
Standart tests include
- Albumin: synthesised in the liver
- Bilirubin
- Alkaline Phosphatase
- ALT (alanine amino-transferase) (incleased in liver inflammation)
Which additives are added to a blood taking tube with a red top?
When is it used?
Nothing has been added
–> used for thyroid/endocrine testing, renal + urine testing, liver function tests and
–> tube has no anti-coagulants–> cuagulants are used up and serum is still there
What is blood serum?
Blood plasma without coagulation factors
What is blood plasma
Non-cellular component of blood (with coagulation factors)
Which additives have been added to a blood taking tube when it has a yellow top?
Gel has been added, speeding up coagulation –> useful for serum collection
- used in U&E testing, Endocrine testing (Thyroid function test), liver test
Which additives have been added to a tube with a purple colour?
Why?
When is it used?
anti-coagulant EDTA has been added:
- –> used for plasma sampling (includes anti-coagulants)
- Used for HBA1c sampling
Which additive has been added to a grey tube?
When is it used?
Why?
Used for plasma glucose levels:
- Red cells consume glucose (anaerobic glycolysis), so the longer this is left out, the lower the glucose may read
- Fluoride Oxalate (poison) prevents the red cells from using glucose
When do you need to contact a chemical pathologist?
- Urgent results
- When you want to measure labile hormones such as insulin
- •When you urgently need CSF glucose and protein to be measured
What happens to lab results in dehydration?
Urea= increased
Creatinine= normal (until very very end of dehydration)
When would you do a cardiac enzyme test?
What are you looking for?
Done if someone is suspected to have a heart attack
- Enzymes of destroyed cardiac muscle might leack into the bloodstream
- •Troponins
- Creatine kinase (CK)
- Aspartate amino transferase (AST) (also seen lin liver disease)
- Lactate Dehydrogenase (LDH)
When requesting a plasma glucose level blood test, which tube would you use? Why?
Erythrocytes continue to consume glucose unless killed
–> are killed in grey tuby by flouride oxalate
What is a ESR? When is it done and what might it indicate?
It is the erythrocyte sedimentation rate
–> increases in inflammation (erythrocytes sediment faster in inflammation)
