2. Automated Analyzers and Definitions Flashcards

Question

How do we interpret leukograms

Answer 1

1. look at total leukocyte and differential counts this number is used to calculate the absolute differential counts total leukocyte count x cell % ex. neutrophils represent 60% of the WBC's in the differential cound; total WBC count is 10.0x10^9/L - absolute neutrophil count = 10.0x10^9/L x 60% = 6.0x10^9/L

Answer 2

Dec - look @ absolute count for each cell and determine which is dec Inc - look @ absolute count for each cell and determine which is inc Normal - look @ absolute count for each cell and determine which is within its normal reference range

Answer 3

1. look at the total leukocyte and differential counts 2. look for morphological abnormalities 3. look for abnormal cell types (atypical cells) 4. Immature cell stages

Answer 4

count all nucleated cells, may include nucleated RBC's will cause total leuko count to be artificially high mathematical adjustments will be req when nucleated RBC's are seen on the differential smear

Answer 5

these cells didn't divide as often during development, or cytoplasm and nucleus develop along diff courses -usually only classified as granulocyte or agranulocyte and are recorded as atypical cells on the differential blood film report sheet -1-2% is normal and are not recoded on report sheet in doubt, ask for 2nd opinon

Answer 6

1 photometry is most common electrochemical light-scatter techniques

Answer 7

machines used is a spectrophotometer which prods light of various wavelengths via filters, prisms or diffraction gratings Spectrophotometers are designed to measure the amount of light transmitted thru a solution Has basic components such as a light source, prism, wavelength selector, photodetector and a read out device

Answer 8

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 chem system

Answer 9

a direct linear relationship btw the conc of an analyte and the light absorption when monochromatic light is passed thru the sample The transmission of the monochromatic light thru a sample and the conc of an analyte in the sample have an inverse exponential relationship the degree of color change is proportional to the solution's conc

Answer 10

When we know how much light is prod + how much of that light passed thru the solution to the detector, we can calculate the amount of light that was absorbed by the patient sample Analyte - what we are measuring. Ex. K High conc of analyte: more light absorbed as passes thru the solution = less light will reach detector Low con of analyte: less light is absorbed as it passes thru the solution = more light will reach the detector The higher the conc of analyte the greater the color change of the detector

Answer 11

1. end point 2. kinetic

Answer 12

measures the conc of pre-existing substances in the serum or plasma involves a chem reaction that reaches a /stable end point/ and measures the color change an int standard curve is created when the instrument is calibrated - must be recalibrated w/ each new reagent. A standard is used for calibration

Answer 13

generally used to measure enzyme assays or when enzyme based reagents are used reaction results are measured at a specific time after the initiation of the reaction does NOT reach a stable end point

Answer 14

Enzyme activity is greatly inhibited by low temperatures and accerlated by high temps Most assays performed btw 30-37C (for every 10C inc above optimal temp, enzyme activity doubles. Monitor incubators and water baths closely) enzymes are proteins! they are denatured by temp, pH extremes, organic solvents, heavy metals or physically damage. HANDLE CAREFULLY

Answer 15

AKA ion-selective electrode (ISE) technology some use this + photometric methods Common to measure electrolytes Diff in electrical potential btw the electrodes is proportional to the conc of the ion in the sample

Answer 16

Potentiometer contains reference electrodes - reference electrodes interact w/ only ONE type of ion and contain a known conc of that ion The patient sample interacts w/ a second ion specific electrode which is located within biosensor reagent strip or cartridge there is a voltage diff btw the electrodes which is used to calculate the conc of the ion in the sample

Answer 17

used to measure the conc of larger molecules in fluids like immunoglobulins, AG-AB complexes, drugs, etc detects the reduction of the intensity of a light as it passes from the light source, thru a solution

Answer 18

Automated analyzers use liquid reagents, dry reagents or slides that contain dry reagents almost all systems can now be integrated so that results are inserted directly into the patients e-file (eliminates missed charges and accessible thruout hospital

Answer 19

these incluse systems that use reagent impregnated slides, pads or cartridges (catalyst Dx and VetTest) Most used reflectance photometry There is little to no handling or storage concerns for reagents tend to be a little more expensive to run Sample rejection is common particularly w/ lipemic, hemolyzed or large animals amples can perform individual or single assay tests slides do allow for loading of a large # of slides at once reducing time needed to run a complete profile

Answer 20

include systems that use lyophilizes reagent or already prepared liquid reagent most common is lyophilized rotor technology (vet scan, rotor is made up of individual cuvettes that diluted sample is added to) cannot run individual tests

Answer 21

tend to be quite accurate require more handling and storage space unitized systems require less handling but are more expensive there are also systems that use bulk reagents (these systems can run individual tests, reagent solutions may or may not need to be diluted, some have extensive maintenance requirements)

Answer 22

most utilize electrochemical methods used to test a specific substance are used when only once substance is being tested blood glucose monitors (alpha trak 2)