automated sample analysis Flashcards

(51 cards)

1
Q

types of automated analysers?

(6 marks)

A
  • biochemistry analysers
  • haematology analysers
  • electrolyte blood gas analysers
  • coag analysers
  • snap test analysers
  • urinalysis analysers
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2
Q

use of biochemistry analysers?

(1 mark)

A

measure various biochemical substances within blood

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3
Q

use of haematology analysers?

(1 mark)

A

automatically determine total RBC + WBC counts, differential WBC counts, packed cell vol + platelet counts

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4
Q

use of electolyte / blood gas analysers?

(3 marks)

A

measures plasma electrolyte levers, resp blood gases + ionised calcium
tells us if any electrolyte disturbance that may impact aci base balance
requires use of arterial blood

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5
Q

use of coag analysers?

(2 marks)

A

measure activated partial thromboplastin time + prothrombin time.
identify clotting disorders

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6
Q

use of snap test analysers?

(1 mark)

A

automatically activates, times + interprets SNAP test results

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7
Q

use of urinalysis analysers?

(2 marks)

A

read + interpret urine dipstick for standard biochemical urine parameters.
identification of cells, bacteria, casts + crystals

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8
Q

advantages of analysers?

(9 marks)

A
  • accurate + easy to use
  • fast, reliable methods of blood examination
  • minimise technician error + time required to perform test
  • expedited results for diagnosis of emergancy cases
  • test kits + reagents easily obtained
  • tests can often be run on whole blood / serum
  • improve customer satisfaction - minimal waiting time
  • multiple tests performed at one time
  • machines link to practice managament system + patient record, allowing easy access to results
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9
Q

disadvantages of analysers?

(9 marks)

A
  • training required ensure staff use equipment efficiently + effectively
  • machines costly to purchase + maintain
  • operator error / machine malfunction can delay results + diagnosis
  • errors common with haematology due to fragility of BCs - support with manual testing
  • machine maintainance can be complicated
  • chemical reagens costly + short dates can result in wastage
  • machine cumbersome + require large work space
  • staff member required to run bloods which removes them from rotated tasks
  • reference intervals unavailable for all species
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10
Q

what can be analysed?

(4 marks)

A
  • blood - whole blood, serum / plasma
  • urine
  • faeces
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11
Q

blood in lithium heparin tube seperates into?

(1 mark)

A

plasma, WBCs + platelets, RBCs

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12
Q

blood in plain tibe seperates into?

(1 mark)

A

serum, blood clot

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13
Q

types of interferons?

(3 marks)

A
  • haemolysis
  • icterus
  • lipaemia
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14
Q

what do interferons do?

(1 mark)

A

impact quality of results machine provides

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15
Q

types of biochemistry machines?

(4 marks)

A
  • IDDEX - catalyst one, procyte Dx
  • zoetics - vetscan VS2
  • samsung - biochemistry analyser
  • seamaty - blood chemistry analyser
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16
Q

biochemistry info?

(6 marks)

A
  • run time approx. 8 mins (15m with TT4)
  • 29+ biochem parameters: including FRU, PHEN, ELEC, TT4, UPC
  • fully automatic
  • on-board centrifudge
  • sample size: 100-700ul whole blood, 300ul serum / plasma
  • some can run multiple tests simultaneously
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17
Q

use of biochemisty?

(! mark)

A

give indication of chemical content of blood sample

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18
Q

how do dry chemistry analysers work?

(3 marks)

A
  • reagents provided on impregnated slides / pads
  • machine determines the assay to be performed by reading a bar code / QR on the slide
  • during machine process the sample is placed on the pad + inserted into the machine
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19
Q

how do the layers of dry chemistry analysers work?

(10 marks)

A
  • spreading layer - sample is distributed evenly
  • filtering layer - filters out substances that interfere with results
  • reagent layer - reagent reacts with sample
  • indicator layer - reacted sample collects for spectral analysis
  • support layer - optical interface
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20
Q

what is dry chemistry?

(1 mark)

A

refers to the slides which are impreganted with dry reagent

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21
Q

what the colour change (of dry chemistry) means?

(2 marks)

A

colour change commonly occurs
degree of colour change is proportionate to the chemical concentration

22
Q

how are the results (of dry chemistry generated)?

(1 mark)

A

chemistry concentration is measured + generated as digital reading / result

23
Q

what is wet chemistry?

(2 marks)

A

uses small wells of fluid instead of dry slides
generates specific wavelengths

24
Q

how does wet chemistry work?

(2 marks)

A

light is passed through a liquid sample
intensity of emergant light is measured, converted into electrical energy + displayed digitally

25
advantage of wet chemistry? ## Footnote (4 marks)
* mutliple samples analysed at one time * multiple chemical tests performed * improved accuracy of results * because more sensitive than dry chemistry
26
disadvantages of wet chemistry? ## Footnote (9 marks)
* smaller machines used in praactice labs can be imprecise * cumbersome * require sufficent storage space * large amounts chemicals + consumables needed * can be complicated to operate + maintain * requires daily calibration + maintainance * operator error more common than dry chem * slower to generate results than dry chem * expensive to purchase + maintain
27
types of haematology machines? ## Footnote (2 marks)
* IDDEX - lasercyte Dx, procyte one * zoetis - vetscan HMS
28
info of haematology machines? ## Footnote (9 marks)
* complete blood count - up to 26 parameters * can support synovial abdo + thoracic fluid - * inflammatory cells * include 3-5 part differential depending on species - * identification of WBCs * 30-90ul sample size * 2-10 min run time * some machines can run sample for - * dogs, cats, horses, ferrets, pigs, rabbit, bovine, gerbil, guinea pig
29
use of haematology analysers? ## Footnote (! mark)
provide quantitive analysis of blood cells
30
what techniques can haematology analysers use? ## Footnote (4 marks)
* laser flow cytology * laminar flow inpendence cytology * optical fluorescence cytology * combination of above
31
how does laser flow cytology work? ## Footnote (5 marks)
* beam of laser light projected through the blood * cells within give otu signals when struck which are * picked up by detectors * detects reflectance, transmission, scattering of light by cells allowing them to be identified * each cell analysed giving numerical respresentation of likely overall distribution of cell populations
32
how does laminar impedence flow cytometry work? ## Footnote (5 marks)
* suspension of cells in fluid, pumped through highly sensitive microchip * allows cytometer to extract impedance (electrical resistance) signature from every cell as they pass through small apeture * each time a cell impedes a pulse is produced, * size of pulse determines size of cells * cell counts are determined by number of pulses measured in a given volume of blood over set period of time
33
how does optical fluorescence cytometry work? ## Footnote (2 mark)
* optical elements of flow cytometer direct photons emitted by fluorophores (bound to the cells) to the detection system * detectors convert signal photons from scattered light / florescence to an electrical current allowing cells to be identified
34
how is cell identification determined? ## Footnote (2 marks)
* size + ability to fluoresce * floresce = indicated agrandular, granular + nucleic content
35
use of dot plots? ## Footnote (2 marks)
* allow visual appreciation of ratio of different cells within a sample * visualise results seen in figures
36
how is quality control achieved? ## Footnote (5 marks)
* manual + detailed differntial white cell counts carried out to monitor quality control + highlight cell abnormalities * clean analyser to avoid debris build up + particle interference * preventaitve maintainance - manufacter provided - ensure result accuract * replenish chem reagents as required * update technology with data manufacter provide
37
types of electrolyte machines? ## Footnote (2 marks)
* IDDEX - vetlyte, catalyst one, catalyst Dx, vetstat * zoetis - vetscan 2
38
info of electrolyte machines? ## Footnote (3 marks)
* generally measured by flame photometry * at least 100ul of sample * take whole blood, serum / heprinised plasma (only anticoagulant to be used)
39
how does flame photometry work? ## Footnote (2 marks)
* measures intensity of light emitted when element is exposed to a flame (light source) * flame emited depends on metal ion component within sample
40
how do electrolyte analysers work? ## Footnote (3 marks)
* small analyser = use ion-sensitive electrons * electrical current passed through specific ion-sensitive electrode bathed in chemical * measurement of charged particle taken = identifies ion
41
what are the most common electrolytes used in practice? ## Footnote (3 marks)
* sodium, magnesium * potassium, chloride * calcium run alone as one of the analyser within a CBC panel
42
types of snap analyser machines? ## Footnote (2 marks)
* IDDEX - snap shot analyser + snap pro analyser * zoetis - vetscan vue
43
info of snap analyser machines? ## Footnote (5 marks)
* sample quantities depend on machine used * use whole blood, plasma / serum * accurate results generated in up to 15 mins * used for screening / diagnostic tests * some machines take multiple samples at once
44
feline snap tests? | (what they test for) ## Footnote (6 marks)
* combo (FeLV, FIV) * giardia * FPL * pro BNP * total T4 * bile acids
45
canine snap tests? | (what they test for) ## Footnote (10 marks)
* CPL * 4DX (anaplasma, heartworm, lyme, e.canis) * leishmania * parvo * giardia * total T4 * cortisol * bile acids * leptospirosis * angio
46
consumable storage? ## Footnote (4 marks)
* consumables written in black stored at room temp / * green in fridge / * blue in freezer * expiration date 3 months if room temp
47
advantages of snap tests? ## Footnote (6 marks)
* result in 10 mins * most accurate pet slide tests available * SNAP pro / reader allows integration with PIMS * no other equipment necessary * used as screening test * ease of use
48
disadvantages of snap tests? ## Footnote (3 marks)
* labour intensive * sensitivity / specificity variable (may need follow-up at lab) * vaccination may interfere
49
equipment care? ## Footnote (7 marks)
* instruments sensitive - careful mainaintance * avoid spills that may damage elctrical equipment * switch off + cover equipment when not in use * manufacter operate instruction followed carefully * staff trained before access to equipment * set personal responsible for equipment maintainance - updates + calibrations run regularly * internal + extrernal quality control tests regular to ensure accurate + valid results
50
examples of pre-analytical errors? ## Footnote (3 marks)
* sample collection, preservation + storage * identification errors - give incorrect reference ranges * incorrect sample times - incorrect results
51
examples of analytical errors? ## Footnote (6 marks)
* operator error * improper instrument calibration * errors in pipetting e.g. air bubbles * use of outdated, contaminated / improperly stored reagents * inadequate time for reagents / slides to reach room temp after removal from fridge / freezer prior to use * drug interference - should be obtained prior to meds