Reticulocytes

Question 1

Definition of Reticulocyte

Answer 1

Immature, non-nucleated RBC with >2 blue-stained granulofilamentous materials (reticulum) after supravital staining

Question 2

Normal maturation time for reticulocytes in blood

Answer 2

1 day

Question 3

Normal production of reticulocytes

Answer 3

50 x 10^9/L/day

Question 4

Purpose of Reticulocyte Count

Answer 4

Effective assessment of RBC production by bone marrow; measure of effective erythropoiesis

Question 5

Normal reference range for reticulocyte count in adults

Answer 5

0.5 to 1.5%

Question 6

Normal reference range for reticulocyte count in newborns

Answer 6

1.8 to 5.8% (by 1-2 weeks of age, same as adults)

Question 7

Increased reticulocyte count

Answer 7

First sign of accelerated erythropoiesis; observed in hemolytic anemias, iron deficiency anemia with therapy, thalassemia, sideroblastic anemia, acute and chronic blood loss

Question 8

Decreased reticulocyte count

Answer 8

Observed in aplastic anemia and in conditions where bone marrow is not producing RBCs

Question 9

Conditions associated with increased reticulocyte count

Answer 9

Hemolytic anemias, iron deficiency anemia with therapy, thalassemia, sideroblastic anemia, acute and chronic blood loss

Question 10

Conditions associated with decreased reticulocyte count

Answer 10

Aplastic anemia, conditions with non-functioning bone marrow

Question 11

Supravital Stains used for reticulocyte counting

Answer 11

New Methylene Blue, Brilliant Cresyl Blue

Question 12

Purpose of Miller disk

Answer 12

Calibrated disk placed in the ocular of the microscope

Question 13

Large Square (A) on Miller disk

Answer 13

Used for counting reticulocytes

Question 14

Small Square (B) on Miller disk

Answer 14

Used for counting RBCs

Question 15

Minimum number of cells to count for accurate reticulocyte count

Answer 15

112

Question 16

Method for reticulocyte count

Answer 16

Routine Light Microscope Method, Calibrated Miller Disk Method, Flow Cytometry

Question 17

Incubation time for Routine Light Microscope Method

Answer 17

3 to 10 minutes

Question 18

Amount of blood and supravital stain in Routine Light Microscope Method

Answer 18

2 to 3 drops or around 50 μL each

Question 19

Reticulocyte counting in Routine Light Microscope Method

Answer 19

Count 1000 RBCs under oil immersion (1000x magnification); reticulocytes counted as both RBC and reticulocyte

Question 20

Calculation for Routine Light Microscope Method

Answer 20

Retic (%) = No. of Retics observed x 100 / 1,000 RBCs observed

Question 21

Minimum RBCs to count in small square (B) for Calibrated Miller Disk Method

Answer 21

112 RBCs

Question 22

Counting rule for reticulocytes in Square B (Calibrated Miller Disk Method)

Answer 22

A reticulocyte in square B is counted as both an erythrocyte and a reticulocyte

Question 23

Total RBCs counted in Calibrated Miller Disk Method

Answer 23

1,008 RBCs (theoretically)

Question 24

Computation for Calibrated Miller Disk Method

Answer 24

Retics(%) = (Total retics in Square A / (Total RBCs in Square B x 9)) x 100

Question 25

Most rapid, accurate, and precise method for reticulocyte count

Answer 25

Flow Cytometry

Question 26

Principle of Flow Cytometry for reticulocyte count

Answer 26

Counts reticulocytes based on optical scatter or fluorescence after treatment with fluorescent dyes or nucleic acid stains

Question 27

Test values in Flow Cytometry

Answer 27

Reported in absolute and relative terms

Question 28

Example of Flow Cytometry equipment

Answer 28

Sysmex R-3500

Question 29

Sysmex R-3500 uses this fluorescent dye

Answer 29

Auramine O (supravital fluorescent dye)

Question 30

How reticulocytes are categorized in Sysmex R-3500

Answer 30

Into low-fluorescence, middle-fluorescence, or high-fluorescence regions; less mature reticulocytes show higher fluorescence

Question 31

Sum of middle-fluorescence and high-fluorescence ratios

Answer 31

"Immature Reticulocyte Fraction (IRF)"

Question 32

Purpose of Immature Reticulocyte Fraction (IRF)

Answer 32

Indicates early erythropoiesis, a sensitive index of bone marrow erythropoietic activity

Question 33

IRF reflects

Answer 33

Quantity of reticulocytes with the highest RNA content

Question 34

Immature Reticulocyte Fraction (IRF) helps to indicate

Answer 34

Ratio of immature reticulocytes to total reticulocytes

Question 35

To distinguish types of anemias, use of IRF together with _____

Answer 35

ARC

Question 36

Brilliant cresyl blue in reticulocyte staining

Answer 36

Brilliant cresyl blue stains reticulocytes but shows too much unpredictability for routine use

Question 37

Adjusting dye to blood ratio for anemia or polycythemia

Answer 37

Increase blood proportion for low hematocrit, decrease for high hematocrit

Question 38

Time for reticulocyte staining

Answer 38

Staining should not be less than 10 minutes | not critical

Question 39

Effect of increased blood glucose or heparin to reticulocyte

Answer 39

pale staining

Question 40

Importance of mixing blood and stain well in reticulocytes

Answer 40

Reticulocytes settle on top of RBCs due to lower specific gravity

Question 41

Deep purple using NMB, nuclear fragments (DNA)

Answer 41

Howell Jolly Bodies

Question 42

Light blue-green, denatured and precipitated hemoglobin, usually at the peripheral edge of the RBC

Answer 42

Heinz Bodies

Question 43

Purple, small cluster of granules, confirmed with Wright or Prussian blue stain, hemosiderin in mitochondria

Answer 43

Pappenheimer Bodies

Question 44

Greenish-blue, multiple small dots, seen in alpha thalassemia

Answer 44

Hemoglobin H

Question 45

Actual number of reticulocytes in 1 liter of whole blood

Answer 45

ABSOLUTE RETICULOCYTE COUNT

Question 46

Corrects reticulocyte count to a normal Hct of 0.45 L/L for anemia degree

Answer 46

CORRECTED RETICULOCYTE COUNT

Question 47

Refines CRC, indicating erythrocyte production increase in anemias

Answer 47

RETICULOCYTE PRODUCTION INDEX

Question 48

Computation for ARC

Answer 48

ARC = (reticulocytes (%) x RBC count (x10^12/L))/100 x 1,000

Question 49

Reference range for ARC

Answer 49

20 to 115 X 10^9/L

Question 50

CRC formula

Answer 50

CRC = Retics (%) x (Hct in L/L / 0.45 L/L)

Question 51

RPI formula

Answer 51

RPI = Corrected Reticulocyte Count / Maturation Time in peripheral blood

Question 52

Hematocrit (%) 40 to 45 Maturation Time (Days)

Answer 52

1

Question 53

Hematocrit (%) 35 to 39 Maturation Time (Days)

Answer 53

1.5

Question 54

Hematocrit (%) 25 to 34 Maturation Time (Days)

Answer 54

2

Question 55

Hematocrit (%) 15 to 24 Maturation Time (Days)

Answer 55

2.5

Question 56

Hematocrit (%) <15 Maturation Time (Days)

Answer 56

3

Question 57

# RPI Generally indicates adequate bone marrow response

Answer 57

"RPI >3"

Question 58

# RPI Generally indicates inadequate bone marrow response

Answer 58

"RPI <2"