biochemistry (done) Flashcards
measurements of pre-analytical panal?
(6 marks)
- blood urea nitrogen (BUN)
- creatinine
- alkaline phosphate (ALKP)
- alanine transferase (ALT)
- total protein (TP)
- glucose
measurements of general health profile?
(12 marks)
- blood urea nitrogen (BUN)
- creatinine
- alkaline phosphatase (ALKP)
- alanine transferase (ALT)
- total bilirubin
- total protein (TP)
- albumin (ALB)
- globulin
- amylase
- glucose
- calcium
- phosphate
why might we perform biochem test?
(5 marks)
- pre GA
- monitoing disease progression
- screening for systemic disease
- highlight subclinical disease
- discretionary diagnostic tool
what do the results of the biochem test allow?
(6 marks)
- confirm suspected diagnosis
- aid in differential diagnosis
- assess severity of disease
- monitor progress
- monitor side effects / disease progression
- monitor therapy
what sample tube does biochem test require?
(1 mark)
lithium hepaprin anticoagulant / serum gel tubes
use of serum gel tube?
(2 marks)
prevent sample from haemolysing during transport
once spun down, blood portions remain seperate.
use of fluoride oxalate tube?
(2 marks)
use if sent to lab for glucose - glucose is used up whilst sitting in blood so lower results seen if not
types of biochemistry analyser?
(2 marks)
- minimum dat base kits e.g. glucometer
- dry + wet chemistry machine e.g. catalyst one
RVN role
(1 mark)
interpret abnormalities in core analytes and inform VS
what are the renal parameters?
(3 marks)
- urea (BUN)
- creatinine
- SDMA
use of urea testing?
(3 marks)
- UREA = 80-90% of nitrogenous waste excreted by the body
- identify renal dysfunction
- NOTE: high BUN can be result of high protein diet
what does the concentration of BUN within plasma depend on?
(3 marks)
- body protein uptake
- body capacity to catabolise proteins
- body ability to excrete this metabolite
interpretation of urea results?
(2 marks)
other influential factors can impact results so additional diagnostics required - urinalysis testing + phosphorus reading taken
use of creatinine testing?
(3 marks)
- creatinine and phosphocreatinine facilitate muscle contraction
- more useful indicator of renal function
- level can be influenced by patients muscle mass/injury
interpretation of creatinine results?
(3 marks)
- indicate filtration capacity of glomerulus
- may not be apparant until significant damage occured
- if GFR decrease = increase CREA.
use of SDMA testing?
(3 marks)
- biomarker of glomeruluar filtration
- more accurate than BUN and creatinine
- allows kidney disease to be identified earlier
use of alkaline phosphate (ALKP) testing?
(liver parameter)
(2 marks)
- hepatic function decreased - ALKP released into blood (elevated)
- increase during pregnancy + bone growth - additional testing
use of alanine aminotransferase (ALT) testing?
(liver parameter)
(3 marks)
- enzyme found in liver
- indicator of hepatocellualr injury - not liver disease
- increase seen with severe muscle injury, hepatocyte degeneration, cardiac insufficency, inflammatory disorders
what are the 3 sources from which glucose is derived?
(6 marks)
- intestinal absorption - dietary carbohydrate broken down + absorbed in intestine
- hepatic production - gluconeogenesis = formation of glucose from non-carb sources, glycogenolysis = conversion of stored glycogen to glucose
- kidney production - glucogenesis
interpretation of glucose parameters?
(3 marks)
- hyperglycaemia seen as result of lack of insulin - also transient stress response (cats)
- hypo seen with insulin OD, exercise, poor nutrition, ingestion of toxins, pregnancy + stress
- single test not sufficent to detect significatn clinical disorder - supporting tests = urine dip + fructosamine
use of bile acid stimulation test?
(1 mark)
determine liver function as healthy liver can extrete bile acids + damaged liver can not.
what tests are done alongside bile acid stim test?
(1 mark)
ALKP and ALT test
what does a bile acid stim test involve?
(4 marks)
- obtain fasted blood sample (12hrs)
- feed patient fatty meal to induce gall bladder contraction
- resample after 2 hours
* sample should be carefully labelled pre + post prandial
use of ACTH stim test?
(2 marks)
- test adrenal gland function by assessing plasma cortisol levels before + after inj of synthetic ACTH (can body produce cortisol in responce to ACTH?)
- allows diagnoses of cushing and addisons
what does an ACTH stim test involve?
(4 marks)
- unmedicated IV blood sample (off meds for 6h at least)
- administration of IV synthetic ATCH - stim production of cortisol
- re-sample 30-60mins post inj
* samples carefully labelled T=0 and T=30mins
use of T3/T4/TSH tests?
(1 mark)
evaluates thyroid function allowing identification of hyppo/hyperthyroidism
errors in anaylsis + reporting
(6 marks)
- sample haemolysis will result in an increase in potassium, magnesium + phosphorus
- icteric + lipaemic sample can impact result
- ensure samples labelled to avoid mixing of patient results
- EDTA markedly increase potassium + decrease calcium results
- predominantly sample into lithium heparin, some specify serum
- ensuring correct tube is used
quality assurance
(8 marks)
- suitable sampling technique
- suitable preservation / anticoagulant
- regular maintenance / servicing
- regular calibration
- appropriate response to result
- use external lab to confirm unexpected result
- sufficient training of personnel to avoid handler error
- ensure chemistry dry slides / wet chem are in date and stored to manufacter guide
how does the ELISA test work?
(3 marks)
- enzyme linked immunosorbent essay
- sample combined with conjugate containing enzyme linked antigen specific antibody
- antibody binds to antigen in infected animal = result in colour change
ELISA tests used in practice?
(6 marks)
- FIV / FeLV combo
- SNAP parvo
- Canine Snap cPL
- ovuCHECK premate test
- ACTH stim test
- T4 snap test
advantages of ELISA?
(5 marks)
- equip and reagents inexpensive with long shelf life
- widely available
- highly specific and sensitive
- quick and easy to perform with rapid results
- snap electronic readers now available to reduce incidence of operator
disadvantages of ELISA?
(4 marks)
- enzyme activity may be affected by plasma constituents
- can be time consuming, as must be timed
- false positives and negatives can occur
- commercially available but can be expensive
