Unit 2 Flashcards

Question

What is a WBC estimation

Answer 1

Used as a quality control measure for both manual and automated counts Estimation of the total WBC count is done with the differential blood smear (#WBC/high dry fields) x2= #WBCx10^9/L

Answer 2

1) look at the total leukocyte concentration (this is used to calculate absolute differential conc. (Total leukocyte conc. x cell type % differential count) 2) look for morphological abnormalities 3) look for abnormal cell types (1-2% is not reported) 4) look for immature cell stages

Answer 3

Counting nucleated RBCs

Answer 4

Photometry (most common) Electrochemical Light-scatter techniques

Answer 5

Machine is a spectrophotometer: produces light of various wavelengths, Designed to measure the amount of light transmitted through a solution Components: light source, prism, wavelength selector, photo detector, read out device

Answer 6

Absorbance: how much light did not reach the detector (uses wet/rotor technology) Reflectance: how much light was reflected off a test substance (used by most in-house analyzers, uses a dry/slide chemistry system)

Answer 7

We know how much light was produced, and how much light passes through the solution to the detector, we can calculate the light absorbed by the analyte High conc. Of the analyte: more light is absorbed by the analyte and less reaches the detector Low conc. Of analyte: less light is absorbed by the analyte and more reached the detector

Answer 8

End point: measures the concentration of pre-existing substances in the serum or plasma, involves a chemical reaction that reaches a stable end point and measures a color change Kinetic: generally used to measure enzyme assays or when enzyme based reagents are used. Reaction results are measured at specific time after the initiation of the reaction. Does NOT reach a stable end point

Answer 9

Inhibited by low temps Accelerated by high temps Most done at 30-37 degrees C

Answer 10

Enzymes are proteins: denatured by temperature, pH extremes, organic solvents, heavy metals or physical damage

Answer 11

Most commonly used to measure electrolytes, also referred to as potentiometers Reference electrodes interact with only one type of ion and contain a known concentration of that ion The sample interacts with a second ion specific electrode in a biosensor reagent strip or cartridge The two electrodes create a voltage difference which is used to calculate the concentration of the ion in the sample The difference in electrical potential between the electrodes is proportional to the concentration of the ion in the sample

Answer 12

Measure the electrical potential between two electrodes

Answer 13

Used to measure the concentration of larger molecules in fluid (immunoglobulins, antigen-antibody complexes, drugs, etc) Detects the reduction of the intensity of a light as it passes from the light source through a solution

Answer 14

Include systems that use reagent impregnated slides, pads or cartridges Most use reflectance photometry

Answer 15

Little to no handling/storage concerns Can perform individual or single assay tests Allows for loading of a large number of slides at once which reduces time A bit more expensive to run Sample rejection is common esp with lipemia, hemolysis and large animals

Answer 16

Systems that use lyophilized reagent or already prepared liquid reagent Most common is the lyophilized rotor technology (rotor is made of individual cuvettes that diluted sample Is added to May also use bulk reagents: can run individual tests, reagent may or may not need to be diluted, extensive maintenance)

Answer 17

Quite accurate Cannot run individual tests More handling/storage concern (more expensive systems may have less handling concerns)

Answer 18

Most utilize electrochemical methods Test for a specific substance (only one substance) Ex. Blood glucose monitors

Unit 2 Flashcards

(42 cards)