Hematology Rotation Quiz 1 Flashcards
- Into what three layers does anticoagulated blood settle when centrifuged or allowed to settle over time?
Upper layer – plasma
Middle layer – buffy coat which contains the white blood cells and platelets
Bottom layer – red blood cells
Venipuncture above an IV line:
Dilution and contamination of the specimen. Decreased RBC, Hgb, WBC, Plt.
What is the anticoagulant of choice for CBC? Storage and Temp limits?
K2 EDTA. Stored at 4 to 8 degrees C, EDTA blood samples with normal results may be analyzed up to 48 hours without significant loss of differential stability. Sample stability at room temperature is 24 hours. Samples stored at room temperature may exhibit an increase in MCV after 24 hours, which may be minimized by refrigeration. Allow refrigerated samples to come to room temperature and mix well before analysis.
Other anticoagulants?
Na Heparin (green top) samples can be used for the HGB & HCT in an emergency only. Blood gas specimens can be used for the HGB & HCT in an emergency only. Citrated (blue top) blood can be used for platelet counts provided a correction is made for the dilution factor. The factor is 1.11 and a slide must be made from the citrated tube and correlated with the platelet estimate. For example, if the platelet count is 150,000, it is multiplied by the dilution factor (150,000 X 1.11 = 166500). The reported platelet count off the blue top tube would be 166,500. Blood from a pink top tube (EDTA tube used for blood bank) is acceptable but cannot be directly ran on the instrument. An aliquot label must be created. A sample from this tube must be obtained for testing before blood bank spins it down and removes the plasma. Cord blood is unacceptable.
What is a Romanowsky Stain?
A stain made from water-soluble eosin, methylene blue, and absolute methanol. It used in Parasitology, Hematology, and Histology/Cytology. An example would be Wright-Giemsa stain.
Hematocrit
Hematocrit is the ratio of the volume of red blood cells to the total volume of blood. It is expressed as a percentage.
standard formula for calculating the number of cells counted in a hemocytometer.
Number of cells per ul or mm3 =
Number of cells counted x dilution x depth / Number of squares counted
Identify the standard diluent for manual RBC counts in our lab, and why it is the diluent of choice.
The standard diluent for manual RBC counting is 0.9% normal saline. This solution is isotonic to RBC. At SFMC, we use Cellpack DCL, manufactured by Sysmex.
SLIGHTLY BLOODY OR SLIGHTLY CLOUDY SAMPLE:
1:20 dilution: 100 ul of specimen and 1.90 ml of Cellpack DCL
MODERATELY BLOODY OR CLOUDY SAMPLE:
1:100 dilution using 20 ul of specimen and 1.98 ml of Cellpack DCL
GROSSLY BLOODY OR TURBID SAMPLE:
1:200 using 10 ul of specimen and 1.99 ml of Cellpack DCL OR
1:200 using 20 ul of specimen and 3.98 ml of Cellpack DCL
Why are both sides of the Hemocytometer utilized?
Counting both sides of the hemocytometer is a QA check for proper pipette and plating technique. The cell count on one side of the hemocytometer should match the cell count from the other side within 20%.
normal ranges for WBCs in males; females; newborns
female, male and child: 4,000-12000
newborn: 5000-21000
iSED Quantitative Capillary Photometry:
The iSED uses quantitative capillary photometry (aggregation) to measure the
sedimentation rate faster than traditional methodologies by capturing the kinetics of RBC
aggregation in a controlled testing environment during the most critical phase of
sedimentation. This critical phase is referred to as the lag or Rouleaux formation phase.
List the ESR method currently used at Saint Francis and the normal ranges.
The iSED is the method currently in use at OSF. The normal ranges are as follows:
Male <50 yrs: 0-15 mm/hr
Male >50 yrs: 0-20 mm/hr
Female <50 yrs: 0 – 20 mm/hr
Female >50 yrs: 0-30 mm/hr
Infant to Puberty: 3 – 13 mm/hr
Newborn: 0-2 mm/hr
What is the significance of the ESR?
The ESR is a simple non-specific screening test that indirectly measures the presence of inflammation in the body. It reflects the tendency of red blood cells to settle more rapidly in the face of some disease states such as acute and chronic infections, tumors and degenerative diseases, usually because of increases in plasma fibrinogen, immunoglobulins, and other acute-phase reaction proteins. The greatest usefulness of this test lies in its ability to differentiate among diseases with similar symptoms or to monitor the course of a disease. Changes in red cell shape or numbers may also affect the ESR.
State whether the ESR would be normal or increased in the following conditions and why?
pregnancy: normal to increased
severe anemia: markedly increased
polycythemia: normal
poikilocytosis: normal to decreased
multiple myeloma: increased
What is the correct method of correlating the automated WBC count with a WBC estimate from the peripheral blood smear? What is the acceptable limit?
To perform a WBC estimate, scan 5 fields on 50 X and add up the total number of WBC’s seen. Divide this number by 3. The WBC estimate should be +/- 20% of the automated count. For example: 24 WBC’s are counted in 5 fields on 50 X. The WBC estimate is 24 divided by 3. The WBC estimate is 8
What is the correct method of correlating the automated platelet count with a peripheral smear estimate? What is the acceptable limit?
Scan 5 fields on 100X and add up the total number of platelets. Divide this number by 5 to find the average number of platelets per field. Multiply this number by 15000. The platelet estimate should be +/- 20% of the automated count. For example: 50 platelet are counted in 5 fields on 100 X. 50 divided by 5= 10. 15000 X 10 = 150000.
Explain how an absolute cell count is calculated for any given cell line. Use the example: WBC count = 6.7 x 103/ul; 67% neutrophils; 1.3% basophils.
The absolute count of a cell is calculated by multiplying the WBC count by reported percent of the cell. For example 6700 X 0.67 = 4489. The absolute neutrophil count is 4489. For the basophil count: 6700 X 0.013 = 87.1. The absolute basophil count is 87.
Absolute Lymphocytosis
An increase in the amount of lymphocytes in the blood that exceeds the upper limit of the normal reference range.
Absolute Neutropenia
A decrease in the amount of neutrophils in the blood that is below the lower limit of the normal reference range.
Absolute Monocytosis
An increase in the amount of monocytes in the blood that exceeds the upper limit of the normal reference range.
What is indicated by Reticulocytosis?
Reticulocytosis is a condition where there is an increase in reticulocytes (immature red blood cells). It is commonly seen in anemia. Reticulocytes are seen on blood films when the bone marrow is highly active in an attempt to replace red blood cell loss such as in hemolytic anemia or hemorrhage.
