Flow Cytometry and Laboratory Automation

Question 1

Cell Flow Cytometry

Answer 1

○ Automated process that analyzes cells or beads in fluid suspensions for their light scattering characteristics
○ Uses fluorochromes to identify cells or particles by size, shape, and antigenic properties

Question 2

Cell Flow Cytometry: Uses

Answer 2

○ Identifying HIV infection
○ Immunophenotyping of cells
○ Diagnosis of leukemia and lymphoma
○ Functional assays for various conditions

Question 3

Sample Preparation: Whole Blood

Answer 3

○ Should be collected into EDTA if sample is to be processed within 30 hours
○ Should be stored at 20°C to 25°C

Question 4

Sample preparation: Peripheral blood, bone marrow, samples with large numbers of RBCs

Answer 4

Require erythrocyte removal

Question 5

Sample preparation: Tissue specimens

Answer 5

○ Should be collected and transported in tissue culture medium
○ May be at room temperature for imminent analysis; at 4°C if analysis is delayed

Question 6

Clinical Applications of Flow Cytometry

Answer 6

○ Identifies particular markers for diagnosis and monitoring of leukemias and lymphomas
○ Enumerates peripheral blood CD4+ T cells to classify stages of HIV disease and guide treatment
○ Determines DNA content or ploidy status of tumor cells

Question 7

Immunoassay Automation

Answer 7

○ Reduces errors
○ Is more accurate and precise
○ Requires fewer staff
○ Saves on controls, duplicates, dilutions, and repeats
○ Potential for better sample identification with use of bar coding

Question 8

Batch analyzers

Answer 8

○ Can examine multiple samples
Permit one type of analysis at a time

Question 9

Random-access analyzers

Answer 9

Measure numerous analytes from multiple samples

Question 10

Accuracy

Answer 10

test’s ability to measure what it claims to measure

Question 11

Precision

Answer 11

ability to consistently reproduce a result on repeated testing of same sample

Question 12

Analytic sensitivity

Answer 12

the lowest measurable amount of an analyte

Question 13

Analytic specificity

Answer 13

the assay’s ability to generate a negative result when the analyte is not present

Question 14

Reportable range

Answer 14

the range of values that will generate a positive result for the specimens assayed by the test procedure

Question 15

Reference interval

Answer 15

the range of values found in healthy individuals who do not have the condition that is detected by the assay; used to define the expected value of a negative test