UAMS HEMATOLOGY MAIN EXAMINATION TEST
QUESTIONS AND ANSWERS GRADED A+
✔✔Sample with EDTA or fingerstick sample, diluting pipettes (old method), or tube
dilutions (recent method). A Neubauer hemocytometer that goes under the microscope
is used to allow counts to be performed in duplicate. It has a chamber with etched grid
lines on each side. - ✔✔What equipment is used for manual cell counts?
✔✔Count 4 large corner squares or all 9 squares on specimens with low cell count. In
the center large square, count the 4 small corner squares and the middle small square.
Count the entire middle large square. - ✔✔How do you count WBC on hemocytometer?
How do you count RBC on hemocytometer? How do you count platelets?
✔✔It is often inaccurate and not necessary. Microhematocrit and hemoglobin
concentration. - ✔✔Why is the manual cell count rarely performed? What are more
accurate manual RBC measurements?
✔✔Inadequate mixing or dilution, non-random distribution, observer bias, or incorrect
calculation. Artifacts - anything the same size as a cell will get counted as a cell,
incorrect interpretation of data, and not utilizing histograms. - ✔✔What are sources of
error in manual counting? What are instrument sources of error?
✔✔Pros: cheap and better for counts less than 100. Cons: time consuming and
imprecise. Pros: fast and improved accuracy and precision. Cons: Costly, anything the
same size as cell gets counted, and cannot be performed on cell counts smaller than
100. - ✔✔What are the pros and cons of manual counts? What are instrument pros and
cons?
✔✔Calibration of automated methods, low cell counts, reference method, and body
fluids. - ✔✔When are manual counts performed?
✔✔If nucleated RBCs are found in the peripheral blood, the WBC has to be corrected. If
NRBCs total 5 or more, a correction will have to be made.
IF NRBCs are found in the peripheral blood during auto-counting, it will be counted as a
WBC which can falsely elevate WBC levels.
WBC x 100 / (100 + NRBCs) - ✔✔What is the correction of WBCs for NRBCs? What is
the formula?
✔✔No because they are much smaller. - ✔✔Can platelets be counted as WBCs?
✔✔Area (9mm^2) x depth (0.1mm) = volume (0.9mm^3) which is equal to 1 uL -
✔✔How is the volume on a hemocytometer calculated?
, ✔✔1% ammonium oxalate, 3% acetic acid, and 1% hydrochloric acid. 1:20 or 1:100. 3%
acetic acid is preferred because it lyses the RBCs to make WBC count easier. It also
has a faster incubation time and is less harmful to work with. - ✔✔What are the typical
diluting fluids for manual WBC counts? What are the dilution factors? What is the
preferred diluting fluid and why?
✔✔Isotonic saline because it will not lyse RBCs because it has the same pH as blood.
1:100. - ✔✔What is the typical diluting fluid for manual RBC counts and why? What is
the dilution factor?
✔✔1% ammonium oxalate. 1:100. - ✔✔What is the typical diluting fluid for platelet
counts? What is the dilution factor?
✔✔It is done by electronic cell impedance. A vacuum pulls WBCs and platelets through
one chamber and RBCs through another. Cells are poor conductors so the current gets
interrupted and the changes in voltage are recorded.
Blood is focused to a single file. Cells interrupt the laser light path and are counted as
they come by. - ✔✔What is the Coulter principle when it comes to automated counting?
What is the light or optical scatter principle when it comes to automated counting?
✔✔Erythroid cells do not have granules whatsoever. Myeloid cells begin to have
granules starting with the promyelocyte. Precursor erythroid cells have navy blue or
royal blue cytoplasm that becomes salmon pink. Myeloid cells have grayish blue or light
blue cytoplasm that becomes pink. - ✔✔What are the biggest differences between
myeloid and erythroid cells?
✔✔To carry O2 from the lungs to the tissues in the form of hemoglobin and return CO2
to the lungs, buffering blood pH. - ✔✔What is the primary responsibility of RBCs?
✔✔In the bone marrow - ✔✔Where does erythropoiesis occur?
✔✔CFU-GEMM gives rise to BFU-E which leads to a large multiclustered colony which
develops into CFU-E.
CFU-E has many receptor sites for EPO and proliferates into pronormablasts which is
the first recognizable erythrocyte precursor in the bone marrow. - ✔✔What are the
cytokines for erythropoiesis? Once the final cytokine has been reached, what happens?
✔✔Erythropoietin. It is produced by the kidneys primarily but can be produced by the
liver in small amounts. It is produced due to stimulation due to oxygen tension in the
blood. It prevents apoptosis of erythroid precursors, induces hemoglobin synthesis, and
is a differentiation factor that causes CFU-E to differentiate into pronormoblasts. -
✔✔What is EPO and what does it do?
QUESTIONS AND ANSWERS GRADED A+
✔✔Sample with EDTA or fingerstick sample, diluting pipettes (old method), or tube
dilutions (recent method). A Neubauer hemocytometer that goes under the microscope
is used to allow counts to be performed in duplicate. It has a chamber with etched grid
lines on each side. - ✔✔What equipment is used for manual cell counts?
✔✔Count 4 large corner squares or all 9 squares on specimens with low cell count. In
the center large square, count the 4 small corner squares and the middle small square.
Count the entire middle large square. - ✔✔How do you count WBC on hemocytometer?
How do you count RBC on hemocytometer? How do you count platelets?
✔✔It is often inaccurate and not necessary. Microhematocrit and hemoglobin
concentration. - ✔✔Why is the manual cell count rarely performed? What are more
accurate manual RBC measurements?
✔✔Inadequate mixing or dilution, non-random distribution, observer bias, or incorrect
calculation. Artifacts - anything the same size as a cell will get counted as a cell,
incorrect interpretation of data, and not utilizing histograms. - ✔✔What are sources of
error in manual counting? What are instrument sources of error?
✔✔Pros: cheap and better for counts less than 100. Cons: time consuming and
imprecise. Pros: fast and improved accuracy and precision. Cons: Costly, anything the
same size as cell gets counted, and cannot be performed on cell counts smaller than
100. - ✔✔What are the pros and cons of manual counts? What are instrument pros and
cons?
✔✔Calibration of automated methods, low cell counts, reference method, and body
fluids. - ✔✔When are manual counts performed?
✔✔If nucleated RBCs are found in the peripheral blood, the WBC has to be corrected. If
NRBCs total 5 or more, a correction will have to be made.
IF NRBCs are found in the peripheral blood during auto-counting, it will be counted as a
WBC which can falsely elevate WBC levels.
WBC x 100 / (100 + NRBCs) - ✔✔What is the correction of WBCs for NRBCs? What is
the formula?
✔✔No because they are much smaller. - ✔✔Can platelets be counted as WBCs?
✔✔Area (9mm^2) x depth (0.1mm) = volume (0.9mm^3) which is equal to 1 uL -
✔✔How is the volume on a hemocytometer calculated?
, ✔✔1% ammonium oxalate, 3% acetic acid, and 1% hydrochloric acid. 1:20 or 1:100. 3%
acetic acid is preferred because it lyses the RBCs to make WBC count easier. It also
has a faster incubation time and is less harmful to work with. - ✔✔What are the typical
diluting fluids for manual WBC counts? What are the dilution factors? What is the
preferred diluting fluid and why?
✔✔Isotonic saline because it will not lyse RBCs because it has the same pH as blood.
1:100. - ✔✔What is the typical diluting fluid for manual RBC counts and why? What is
the dilution factor?
✔✔1% ammonium oxalate. 1:100. - ✔✔What is the typical diluting fluid for platelet
counts? What is the dilution factor?
✔✔It is done by electronic cell impedance. A vacuum pulls WBCs and platelets through
one chamber and RBCs through another. Cells are poor conductors so the current gets
interrupted and the changes in voltage are recorded.
Blood is focused to a single file. Cells interrupt the laser light path and are counted as
they come by. - ✔✔What is the Coulter principle when it comes to automated counting?
What is the light or optical scatter principle when it comes to automated counting?
✔✔Erythroid cells do not have granules whatsoever. Myeloid cells begin to have
granules starting with the promyelocyte. Precursor erythroid cells have navy blue or
royal blue cytoplasm that becomes salmon pink. Myeloid cells have grayish blue or light
blue cytoplasm that becomes pink. - ✔✔What are the biggest differences between
myeloid and erythroid cells?
✔✔To carry O2 from the lungs to the tissues in the form of hemoglobin and return CO2
to the lungs, buffering blood pH. - ✔✔What is the primary responsibility of RBCs?
✔✔In the bone marrow - ✔✔Where does erythropoiesis occur?
✔✔CFU-GEMM gives rise to BFU-E which leads to a large multiclustered colony which
develops into CFU-E.
CFU-E has many receptor sites for EPO and proliferates into pronormablasts which is
the first recognizable erythrocyte precursor in the bone marrow. - ✔✔What are the
cytokines for erythropoiesis? Once the final cytokine has been reached, what happens?
✔✔Erythropoietin. It is produced by the kidneys primarily but can be produced by the
liver in small amounts. It is produced due to stimulation due to oxygen tension in the
blood. It prevents apoptosis of erythroid precursors, induces hemoglobin synthesis, and
is a differentiation factor that causes CFU-E to differentiate into pronormoblasts. -
✔✔What is EPO and what does it do?
