Automation Practice Questions
Which of the following is always calculated on cell counters?
MCHC
All of the following will be invalid when lipemia is present in a blood sample except: MCHC MCV MCH hemoglobin
MCV
Which of the following is true regarding automated reticulocyte counts?
RNA is stained with various dyes that allow for detection of reticulocytes by optical scatter or fluorescence.
What is the recommended method for establishing accuracy of automated hematology analyzers?
Use commercially prepared whole blood calibrators.
Compared to manual methods, automated reticulocyte counting improved which of the following? distribution error statistical sampling error interobserver error all of the above
all of the above
A white blood cell count is done on an automated cell counter from a patient with thalassemia major. The WBC result will be:
an accurate estimate of the WBC concentration (no error due to this disorder)
Right-angle scatter, in a laser-based cell counting system, is used to measure:
cell volume
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 mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC) are elevated. Which of the following is the most likely reason for this failure?
cold agglutinin
How do CELL-DYN instruments differentiate red cells and platelets from one another?
differences in volume (fL) using electrical impedance principle
How do Beckman Coulter and Abbott instruments count red cells and platelets? 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?
electrical impedance
Side (90o) light scatter, when used in an instrument employing the optical scatter principle, correlates with cell:
granules
Which of the following is determined by light transmission between 525 and 555 nm?
hemoglobin
What technology minimizes the problems of a rigid aperture including protein buildup, coincidence, and a single cell being counted twice?
hydrodynamic focusing
The basis for the Coulter principle of electronic particle counting is:
impedance of an electric current by the particles
The most common cause of error when using automated cell counters is:
inadequate mixing of the sample prior to testing
When using an electronic cell counter, which of the following results can occur in the presence of cold agglutinins:
increased MCV and decreased RBC
What is the greatest limitation of automated cell counters?
inherent specimen problems leading to occasional spurious results
On an electronic cell counter, hemoglobin determinations may be falsely elevated owing to the presence of:
lipemia or elevated bilirubin concentration
What principle does the Sysmex SE-9000/9500 use to analyze and separate white cell populations?
low-frequency DC and high-frequency current (DC/RF)
In an automated cell counter with a 3-digit readout capacity, the WBC printed result is 99.9. The next step is to:
make an appropriate dilution of the sample
What does the pneumatic system of cell counters do?
operates the valves and moves the sample
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?
platelet count
On setting up the electronic particle counter in the morning, one of the controls is slightly below the range for the MCV. Which of the following is indicated:
repeat the control
A specimen run on an automatic cell counter has a platelet count of 19 x 103/uL. The first thing the technician should do is:
review the stained blood smear
Forward light scatter, when used in an instrument employing the optical scatter principle, correlates with cell:
size
The corrective action for the presence of cold agglutinins involves:
warming the sample at 37 oC, then re-run
Platelet clumps would most likely interfere with which other automated parameter? In an electronic or laser particle cell counter, clumped platelets may interfere with which of the following parameters
white blood cell count (WBC)
Which of the following occurs if testing is not performed with 24 hours from specimen collection?
white blood cells deteriorate and red blood cells swell