17) Flow cytometry

Question 1

flow cytometry

define threshold

Answer 1

lower or upper size limit set so debris and certain cells can be ignored

Question 2

flow cytometry

define gating

Answer 2

drawing boundaries around cell populations on the dot plot

Question 3

flow cytometry

define monoclonal antibody

Answer 3

Ab with a single specificity

Question 4

flow cytometry

define immunophenotyping

Answer 4

using flow and mAbs to determine the phenotype of a cell population

Question 5

flow cytometry

define hydrodynamic focusing

Answer 5

using sheath fluid and narrowing the flow cell width so that only one cell passes through the laser at a time

Question 6

flow cytometry

define cluster designation

Answer 6

surface marker/receptor

Question 7

define flow cytometry

Answer 7

uses forward scatter, side scatter and fluorescent markers to ID cell populations

Question 8

flow cytometry

function of sheath fluid

Answer 8

suspends cells for hydrodynamic focusing

Question 9

flow cytometry

function of the photomultiplier tube

Answer 9

detector that amplifies the signal

Question 10

flow cytometry

function of isotypic controls

Answer 10

controls used for detecting any nonspecific binding of the mAbs

Question 11

list uses for flow cytometry

Answer 11

• dx leukemias & lymphomas
• distinguishing lymphs from one another
• monitoring HIV pts (CD4+ pop)
• dx PNH (DAF, MIRL, GPI)
• detecting fetal cells
• detecting plt abnormalities
• sorting cells
• detecting missing surface markers in immcomp pts

Question 12

most common limitations or interferences with flow

Answer 12

• agglutination
• old sample (cell viability test)
• not enough cells
• wrong flow cell sample width
• wrong pressure of sheath fluid
• nonspecific binding
• fluorophore choice

Question 13

cell information provided by flow

Answer 13

• forward scatter: size
• side scatter: internal complexity/granularity
• fluorescence: surface markers

Question 14

examples of fluorophores used in flow

Answer 14

• R-PE (phycoerythrin)
• Alexa fluor
• FITC

Question 15

common samples used for flow

Answer 15

• BM aspirate
• PB
• CSF
• lymph node biopsy

Question 16

specimen handling requirements for flow

Answer 16

• room temp or refrigerated, depending on order (never frozen)
• STAT—preferred within 24 hours, accepted within 48 hours after cell viability test