chem path lab

Question 1

what tests are involved for chem path *

Answer 1

liver function test - LFT

urea and electrolytes

blood glucose

calcium and phosphate

hormone assays with endo -TSH, thyroxine, cortisol

Question 2

what does a request form for labs look like *

Answer 2

pic

Question 3

how do you take a sample *

Answer 3

label tube

venepuncture

important to get the right tube

Question 4

what anticoagulants do differnet tubes have *

Answer 4

red - none

yellow - gel to speed up clot

purple - potassium EDtA

grey - fluoride oxalate - poison

Question 5

what tube would you use for U adn E *

Answer 5

serum in yellow/red

Question 6

what tube would you use to test glucose *

Answer 6

plasma in grey

Question 7

what tube would you use to test HBA1c *

Answer 7

plasma in purple

Question 8

what tube would you use for thyroid function tests *

Answer 8

serum in yellow/red

Question 9

what tube would you use for LFT *

Answer 9

yellow/red

Question 10

what is the erythrocyte sedimentation rate *

Answer 10

red cell settle in tube

how far go in 1 hr

if lots of inflamm cell and protein move at a faster rate

if high show somethings wrong

if normal - rule out things

Question 11

why do you test for C reactive protein *

Answer 11

made by liver in infection

eg if high could be septicaemia

Question 12

wat is tested for in liver function test *

Answer 12

liver release enzymes

if enzymes in blood = liver damaged

Question 13

what is makes gammaGT *

Answer 13

liver

Question 14

what happens in red tube

Answer 14

clot in 5min

centrifuge

get serum at the top with no clottomg factor

Question 15

what happens in purple tube *

Answer 15

have EDTA

keeps cells alive

can do full blood count

also have K in - cant use it to measure electrolytes

Question 16

what happens in grey tube *

Answer 16

oxalate is poisen - stops glycolysis, ie stop the red cells consuming the glucose - so measured glucose is correct

also stop clotting so have plasma with clotting factors

Question 17

why would you measure HBA1c *

Answer 17

long term measure of glucose

glycated Hb

high blood glucose - 12%

marker of tissue damage in the heart and brain - tells you about long term glucose control

Question 18

what happens in a yellow tube *

Answer 18

gel to speed up clot

Hb heavy - blood go to bottom

gel in the middle

leave serum at top

red cell loads of k in - dont want in serum when take sample

Question 19

what is the difference between serum and plasma *

Answer 19

plasma has clotting factors

Question 20

is it serum or plasma in red/yellow tubes *

Answer 20

blood clots using all clotting factors

clot can be removed

leaving serum

Question 21

examples of anticoagulants and what happens if they are in tubes *

Answer 21

EDTA/heparin

clotting factor unused

blood can be separated into cells and plasma - centrifuge: if really fast have plasma at top, then lymphocytes and monocytes, then gel, tehn red cells and neutrophils

Question 22

what are blue tubes used for *

Answer 22

measure amount of clotting factor

has citrate - make blood not clot

then add Ca - will clot - time taken to clot shows if have enough clotting factors

Question 23

when do you need to contact the chemical pathologist *

Answer 23

when want the sample to be rapidly centrifuged out of hours

when you wnat to measure labile (rapidly broken down) hormones eg insulin - need to do in 15mins - otherwise clotting damages it

urgently need CSF glucose and protein to be measured - high protein and low glucose suggest bacteria in CSF eg with meningitis

Question 24

what happens to samples *

Answer 24

chemistry carried out on plasma or serum - so need to centrifuge to separate plasma/serum from red cells

Question 25

how do you get the results from chem path \*

Answer 25

on computer if urgent - phoned to clinician

Question 26

how are reference ranges determined \*

Answer 26

take 100 healthy people bottom and top level were... this is the reference range

Question 27

what is a cause of low Na and high K

Answer 27

low aldosterone

Question 28

how can haemolysis of red cells occur, what is the consequence \*

Answer 28

red cell lyse as go through needle cause high K in sample - because would have been in RBC tell because plasma is a rose colour

Question 29

decribe what you are looking for with urea and creatine \*

Answer 29

made by the muscle and excreted by kidney creatine - filitered but not absorbed - give the glomular filtrate rate normal creatinine means the kidneys are ok high urea means tubules not working - because of severe dehydration - GFR stays normal until end so creatinine normal in renal failure both urea and creatinine rise

Question 30

what comes with experience when looking at liver function test

Answer 30

tell what disease the patient has from the pattern of the leak

Question 31

what is included in 'liver' on a request sheet \*

Answer 31

albumin - synth in liver BR alkaline phosphtase ALT (alanine amino-transferase)

Question 32

what would you tick on a request form for someone with jaundice \*

Answer 32

liver AST gammaGT

Question 33

how would you interpret liver function tests \*

Answer 33

low albumin = liver failure high BR - break down too many red cells, or problem with BR excretion alkaline phosphtase high - something affecting bile flow - physical block ALT high - inflammed liver, acute hep high AST - inflam

Question 34

how do you make a diagnosis \*

Answer 34

take history examine pt make a plan - inc tests

Question 35

why do you look at cardiac enzymes \*

Answer 35

present in the heart muscle during HA - heart muscle damaged these enzymes leak into blood at huge amounts tell if someone had HA measure if someone has a history of heart disease might not feel HA - eg diabetic neuropathy

Question 36

what are the cardiac enzymes and what do they show \*

Answer 36

troponins creatine kinase (CK) aspartate amino transferase (AST) lactate dehydrogenase (LDH) can look at pattern to see when MI happened: troponin and CK raise in hours of MI AST - next day LDH - after days AST liver enzyme too - so heart/live rdamage rise AST

Question 37

what do you tick on a request form for cardiac enzymes \*

Answer 37

heart AST

Question 38

role of a chemical pathologist

Answer 38

work in chem path lab metabolic medicine clinics research into better ways of getting results