Electronic blood analysers Flashcards Preview

Nursing support for disease diagnosis > Electronic blood analysers > Flashcards

Flashcards in Electronic blood analysers Deck (13)
Loading flashcards...
1

Describe biochemistry analysers

Measure various biochemical substances within the blood e.g. glucose, total protein, blood urea nitrogen, creatinine etc.

2

Describe haematology analysers

Automatically determine total red and white blood cell counts, differential white blood counts, packed cell volume and platelets counts etc

3

Describe electrolyte analysers

Measure plasma electrolyte levels e.g. sodium, chloride, potassium, bicarbonate etc

4

Describe hormone analysers

Measure blood hormone levels. Commonly carried out at commercial laboratories but thyroxine and cortisol test kits are now available for diagnosis of hyperthyroidism, Cushing disease etc within vet lab

5

What are the advantages of automated blood analysers?

Accurate and easy to use



Rapid results for diagnosis of emergency cases



Test kits and reagents are easily obtained



Rapid results and minimal skill required to operate



Minimal degree of calibration and quality control required to ensure data is accurate.



Reliable and comprehensive technical and educational support available from equipment provider

Fast, reliable method of blood examination



Minimise technician error and time require to perform test

6

What are the disadvantages of automated blood analysers?

Numerous machines available each with a very different technique. Manufactures recommendations should be adhered to for each machine



Errors are common with haematology analysers due to the fragility of blood cells etc therefore supporting results with manual testing is often performed

7

What are the three types of automated haematology machines?

Quantitative Buffy Coat (QBC)

Impedance counter machines – More accurate

Laser Cell counters – More accurate

8

Describe Quantitative Buffy Coat Analyser's (QBC)

Provide:

Total and differential white blood cell counts

Total red blood cell counts



Whole blood pipetted into microhaematocrit tube and float added



Sample spun in centrifuge to separate sample

Float separates buffy coat into constituent cell layers which are measured accordingly



Provides a granulocytes count and a combined mono and lymphocyte count in addition to red blood cell count

9

Describe impedance counter machines

Measures electrical resistance (impedance) as cells pass through a small aperture.



Each time a cell impedes a current a pulse is produced



Cell counts are determined by the number of pulses measured in a given volume of blood over a set period of time.

Size of pulse is proportional to size of cell



Produces large numbers of parameters and accompanying graphs. Some machines also give white cell differentials.

10

Describe laser cell counters

Laser detection systems is used to detect the reflectance, transmission and scattering of light by cells



Each cell is analysed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations.

Provides larger numbers of parameters to illustrate cell distribution for red cells, white cells and platelets.



Produces white cell differentials using peroxidase staining, measurement of cell size and nuclear density.

11

Describe dry chemistry analysers

Reagents are provided on impregnated slides or pads



Serum sample is placed on to the pad and inserted into the machine



The machine determines the assay to be performed by reading a bar code on the slide

A colour change on the pad commonly occurs, the degree of colour change is proportionate to the solution concentration



The solution concentration is measured and generated as a digital reading or result



Most commonly used

Idexx Vet Test chemistry analyser

Catalyst Dx chemistry analyser

12

Describe wet chemistry analysers

Uses small wells of fluid instead of dry slides



Generates specific wavelengths



light is passed through a liquid sample



The intensity of the emergent light is measured, converted into electrical energy and displayed digitally

Multiple samples can be analysed at one time



Multiple chemical tests can be performed at one time



Improved accuracy of results



Specific maintenance requirements

Chemical reagents

Daily calibration

Cleaning etc

13

Describe automated electrolyte analysers

Electrolytes are generally measured by flame photometry in the large commercial laboratories (NaCl (orange) KCl (purple)



Smaller versions used in practice use ion-sensitive electrodes.


An electrical current is passed through a specific ion-sensitive electrode bathed in a chemical and the measurement of the charged particles is taken.



The commonest electrodes used in practice are sodium, potassium and chloride.



Sample quality, particularly haemolysis can strongly affect the results and should be taken into consideration