Hematocrit and RBC indicies

Question 1

Hematocrit reference range (Adult Males)

Answer 1

40 to 54% (0.40 to 0.54 L/L)

Question 2

Hematocrit reference range (Adult Females)

Answer 2

35 to 49% (0.35 to 0.49 L/L)

Question 3

Hematocrit reference range (Newborn)

Answer 3

53 to 65% (0.53 to 0.65 L/L)

Question 4

Pertain to the instrument used to determine packed cell volume (PCV)

Answer 4

Hematocrit

Question 5

The volume of red blood cells that have settled is called packed cell volume

Answer 5

Hematocrit

Question 6

Hematocrit topmost layer

Answer 6

Fatty layer

Question 7

Hematocrit second layer

Answer 7

Plasma

Question 8

Hematocrit third layer

Answer 8

Buffy coat

Question 9

Hematocrit fourth layer

Answer 9

Packed RBC

Question 10

Hematocrit bottom layer

Answer 10

Plug (4-6mm)

Question 11

Length of Micro-Hematocrit Tube

Answer 11

Approx. 75 mm

Question 12

Inner bore of Micro-Hematocrit Tube

Answer 12

1.2 mm

Question 13

Volume of blood a Micro-Hematocrit Tube can hold

Answer 13

0.05 mL

Question 14

Length of the plug in a Micro-Hematocrit Tube

Answer 14

4 to 6 mm

Question 15

Capillary tubes (red banded)

Answer 15

Heparin anticoag; used for direct capillary puncture

Question 16

Capillary tubes (blue band)

Answer 16

No anticoagulant/plain; used for collection with anticoagulant

Question 17

Significance of air bubbles in capillary tubes

Answer 17

Air bubbles denote poor skills but do not affect the test results

Question 18

How to fill capillary tubes with a colored ring

Answer 18

Fill from the opposite end without the colored band

Question 19

Hematocrit centrifugation

Answer 19

Spin for 5 minutes at 10,000 RPM

Question 20

RPM check for hematocrit centrifuge

Answer 20

RPM must be checked periodically with a tachometer

Question 21

Rodak’s Hematology centrifuge recommendation

Answer 21

Centrifuge at 10,000 g to 15,000 g for maximum packing

Question 22

Test result agreement for two patient samples

Answer 22

Results should agree within 1% [+0.01 L/L]

Question 23

Effect of trapped plasma on microhematocrit results

Answer 23

Causes microhematocrit to be 1% to 3% (0.01 to 0.03 L/L) higher than automated instrument results

Question 24

Automated hematocrit

Answer 24

Calculated value from RBC and MCV

Question 25

Conditions with more trapped plasma

Answer 25

Sickle cell anemia, Hypochromic anemia, Spherocytosis, Macrocytosis, Thalassemia

Question 26

Effect of abnormal RBC shapes (e.g., spherocytes, sickle cells) on packing

Answer 26

inhibit complete packing

Question 27

Causes of falsely increased hematocrit

Answer 27

Dehydration, Hemoconcentration, Insufficient centrifugation, Buffy coat inclusion

Question 28

Causes of falsely decreased hematocrit

Answer 28

Hemolysis, Improper sealing, Increased AC concentration, Introduction of excess interstitial fluid

Question 29

Rule of Three

Answer 29

Used to check validity of test results for normocytic, normochromic specimens

Question 30

Rule of Three formula for RBC count

Answer 30

RBC count x 3 = Hb +/- 3

Question 31

Rule of Three formula for Hemoglobin

Answer 31

Hb x 3 = Hct +/- 3

Question 32

Mean Cell Volume (MCV) measures

Answer 32

Average volume of an individual RBC.

Question 33

MCV formula

Answer 33

(HCT/RBC CT) x 10.

Question 34

MCV reference range

Answer 34

80 to 100 femtoliters.

Question 35

MCV in microcytic anemia

Answer 35

less than 80fL.

Question 36

MCV in macrocytic anemia

Answer 36

greater than 100 fL.

Question 37

Mean Cell Hemoglobin (MCH) measures

Answer 37

Average weight of hemoglobin in an individual RBC.

Question 38

MCH formula

Answer 38

(Hb/RBC count) x 10.

Question 39

MCH reference range

Answer 39

26-32 pg.

Question 40

Mean Cell Hemoglobin Concentration (MCHC) measures

Answer 40

Mean concentration of hemoglobin in the average RBC.

Question 41

MCHC formula

Answer 41

Hb/Hct x 100.

Question 42

MCHC in hypochromic anemia

Answer 42

less than 31g/dL.

Question 43

MCHC in hyperchromic RBCs

Answer 43

greater than 37 (true increase in Hereditary spherocytosis).

Question 44

MCHC reference range

Answer 44

31-37 g/dL or %.

Question 45

RBCs cannot hold more hemoglobin than

Answer 45

37 g/dL.

Question 46

Result >37 g/dL for MCHC

Answer 46

Should be recomputed due to possible interference or inaccurate measurement.

Question 47

MCH and MCHC clinical value

Answer 47

Have diminished but are valuable quality control tools.

Question 48

Polycysthemia definition

Answer 48

Increased hematocrit level above normal.

Question 49

Polycysthemia in clinical setting

Answer 49

Elevated hemoglobin and RBC count, reflecting elevated total erythrocyte volume.

Question 50

Two types of polycythemia

Answer 50

Absolute and Relative.

Question 51

Absolute Polycythemia

Answer 51

Elevated total red cell mass.

Question 52

Relative Polycythemia

Answer 52

Normal total red cell mass, increased hematocrit due to decreased plasma volume.

Question 53

Secondary polycythemia with appropriately EPO production (Absolute)

Answer 53

Decreased oxygen loading (hypoxia, high altitude, pulmonary disease, cyanotic heart disease, carboxyhemoglobinemia, methemoglobinemia, Hb M); Decreased oxygen unloading (high oxygen affinity hemoglobinopathy, biphosphoglycerate deficiency).

Question 54

Secondary polycythemia with inappropriately EPO production (Absolute)

Answer 54

Neoplasms (Wilms’ tumor, renal carcinoma, cerebellar hemangioma, hepatoma); Localized tissue hypoxia (polycystic kidney, renal artery stenosis); Post-renal transplant, acute hepatitis.

Question 55

Relative polycythemia

Answer 55

Diminished plasma volume (Dehydration, shock; Spurious Polycythemia: Stress polycythemia, Gaisböck’s syndrome.

Question 56

Secondary polycythemia with Genetic polycythemia (Absolute)

Answer 56

Primary familial congenital polycythemia (mutated Epo receptor); Chuvash polycythemia (mutated VHL gene).

Question 57

Secondary polycythemia with Primary marrow disorders (Absolute)

Answer 57

Polycythemia vera (PV).

Question 58

Polycythemia vera (PV) characteristic

Answer 58

Panmyelosis (excessive proliferation in RBCs, megakaryocytes, granulocytes).

Question 59

Polycythemia vera (PV) hallmark

Answer 59

Plethora.

Question 60

Polycythemia vera (PV) mutation

Answer 60

JAK2 V617 mutation (90%-97% of patients).

Question 61

Polycythemia vera treatment

Answer 61

Therapeutic phlebotomy (aim to maintain hematocrit < 45%) - also used for hemochromatosis