Methods of measurements

Question 1

What are Proficiency testing/quality assurance programs? and give an example of a program

Answer 1

• every 2 weeks external organisation gives you samples & you test it w/ your analysers
• results sent to organisation => compare how close your results were to other labs
• E.g. RCPA quality assurance programs

Question 2

What are external accreditation of quality systems? give an example of an organisation that tests this

Answer 2

organisations like National Association of Aesting Authorities (NATA) to check if lab complies w/ quality systems of international standards for organisations (ISO)

Question 3

principles of flow cytometric based automated analyzer function

Answer 3

• FWD scatter: orthogonal scatter = cell size

- Side/orthogonal scatter: complexity of cytoplasm ie. granularity

Question 4

2 automated methods used to count cellular elements in blood

Answer 4

• electrical impedance

- Optical detection

Question 5

principle of electrical impedance (automated) method

Answer 5

• blood diluted (diluents are good conductors) pass through small aperture @ steady rate
• RBC poor conductors = disrupts current b/w 2 electrodes (no. of times disrupted = no. cells)
• changes in electrical resistance (impedance) are measured => cell count and cell size

Question 6

Principle of optical detection (automated) method

Answer 6

1. steady stream of diluted blood pass through focused laser beam
2. as cells pass = light scatter = detected by photodetector 7 converted to an electrical impulse
3. no. of pulses = number of cells passing through