Deck 15: Automated Blood Cell Analysis

Question 1

Select the most appropriate action for the results in Question 18.

A)Report the results.
B)Lyse the red cells manually and rerun.
C)Warm sample to 37° C and rerun.
D)Replace plasma with saline and rerun.

Answer 1

Warm sample to 37° C and rerun.

Question 2

How do Beckman Coulter and Abbott instruments count red cells and platelets?

A)florescent staining and enumeration
B)survival staining and conductivity
C)optical scatter
D)electrical impedance

Answer 2

electrical impedance

Question 3

Platelet clumps would most likely interfere with which other automated parameter?

A)WBC count
B)RBC
C)hemoglobin
D)red cell indices

Answer 3

WBC count

Question 4

An elevated immature reticulocyte fraction is associated with

A)bone marrow suppression.
B)chemotherapy.
C)bone marrow response to anemia.
D)renal disease.

Question 5

Which of the following uses a peroxidase stain channel?

A)Siemens Healthcare Diagnostics ADVIA 2120
B)Coulter LH750
C)Sysmex SE-9000
D)Abbott CELL-DYN 4000

Question 6

Compared with manual methods,automated reticulocyte counting improved which of the following?

A)distribution error
B)statistical sampling error
C)interobserver error
D)all of the above

Question 7

Which of the following is determined by light transmission between 525 and 555 nm on automated counting instrumentation?

A)reticulocytes
B)hemoglobin
C)mean cell volume (MCV)
D)mean cell hemoglobin (MCH)

Question 8

Counting the number and size of electrical interferences created by blood cells as they pass through a small aperture is a description of which of the following principles?

A)electronic impedance
B)optical scatter
C)conductivity
D)laminar flow

Question 9

All of the following will be invalid when lipemia is present in a blood sample except

A)MCHC.
B)MCV.
C)MCH.
D)hemoglobin.

Question 10

An automated hematology analyzer is used to evaluate a blood specimen.Which of the following,coming off the instrument,would require performance of a manual white cell differential as opposed to blood film review?

A)flagged data
B)suppression of automated differential data
C)abnormal red cell indices
D)a slightly elevated platelet count

Question 11

A patient sample comes off an automated cell counter with a failure of the red cell "rule of three." The red count is lower than expected given the hemoglobin.The MCV,MCH,and MCHC are elevated.Which of the following is the most likely reason for this failure?

A)megaloblastic anemia
B)lyse-resistant red cells
C)cold agglutinin
D)lipemia

Question 12

Which of the following is true regarding automated reticulocyte counts?

A)This was one of the earlier cell-counting methods to be automated.
B)Ribonucleic acid (RNA) is stained with various dyes that allow for detection of reticulocytes by optical scatter or fluorescence.
C)They are more accurate but less precise than the manual method.
D)They require significantly more time to count reticulocytes than manual methods.

Question 13

How do CELL-DYN instruments differentiate red cells and platelets from one another?

A)differences in forward scatter using optical light scatter principle
B)use of a unique reagent that selectively lyses red cells while preserving platelets
C)differences in volume (fL) using electrical impedance principle
D)use of a unique reagent that selectively lyses platelets while preserving red cells

Question 14

Which of the following is always calculated on cell counters?

A)hematocrit
B)MCV
C)mean cell hemoglobin concentration (MCHC)
D)red blood cell count

Question 15

What is the greatest limitation of automated cell counters?

A)poor precision
B)speed
C)unavailability of quality control materials
D)inherent specimen problems leading to occasional spurious results

Question 16

What is the mechanism for the three-part differential found in older Coulter machines or those designed for smaller laboratories?

A)volume, conductivity, scatter
B)multiangle polarized scatter separation
C)peroxidase staining and light scatter
D)impedance after cytoplasm shrinkage

Question 17

What does the pneumatic system of cell counters do?

A)operates the valves and moves the sample
B)controls computer software
C)digitizes the pulses generated by cell passage
D)controls the laser light

Question 18

Forward light scatter,when used in an instrument using the optical scatter principle,correlates with cell

A)granules
B)volume
C)nuclear chromatin
D)number

Question 19

What technology minimizes the problems of a rigid aperture,including protein buildup,coincidence,and a single cell being counted twice?

A)forward scatter
B)radiofrequency
C)hydrodynamic focusing
D)fluorescence

Question 20

What principle does the Sysmex SE-9000/9500 use to analyze and separate white cell populations?

A)electronic impedance
B)optical light scatter
C)volume, conductivity, and scatter
D)low-frequency direct current and high-frequency current

Question 21

Platelet volume normally

A)is 15 to 20 fL.
B)increases as the sample sits in ethylenediaminetetraacetic acid (EDTA).
C)is 5 to 18 fL.
D)is not reliable on most electronic instruments.

Question 22

Which of the following occurs if testing is not performed within 24 hours of specimen collection?

A)White blood count rises.
B)WBCs deteriorate and RBCs swell.
C)Hemoglobin rises.
D)MCV decreases.

Question 23

When the electronic impedance principle is used to count blood cells,what is done to increase platelet-counting sensitivity?

A)Decrease the size of the RBC/platelet aperture.
B)Increase the size of the RBC/platelet aperture.
C)Use a strong lysing agent to selectively lyse the RBCs.
D)Lower the upper threshold for counting platelets so that even microcytic red cells are excluded.

Question 24

A patient's white blood count comes off an automated cell counter as 380 * 10⁹/L.Which of the following could be reported without any additional testing?

A)red blood count
B)hemoglobin
C)hematocrit
D)platelet count

Question 25

What is the recommended method for establishing accuracy of automated hematology analyzers?

A)Use at least three levels of controls for calibration.
B)Use whole blood calibration methodology.
C)Use commercially prepared whole blood calibrators.
D)Perform manual methods for comparison.