Erythrocytes

Question 1

Manual RBC counts usage

Answer 1

Rarely done due to inaccuracy; better alternatives like microhematocrit and hemoglobin concentration are preferred.

Question 2

Effect of high altitude on RBC count

Answer 2

Elevated, with ~1 g Hb/dL increase at 2 km altitude and ~2 g Hb/dL increase at 3 km altitude.

Question 3

RBC count reference range for children (8-13 y.o.)

Answer 3

4.00 to 5.40 X 10^6/µL or 4.00 to 5.40 X 10^12/L.

Question 4

RBC count reference range for adult males

Answer 4

4.60 to 6.00 X 10^6/µL or 4.60 to 6.00 X 10^12/L.

Question 5

RBC count reference range for adult females

Answer 5

4.00 to 5.40 X 10^6/µL or 4.00 to 5.40 X 10^12/L.

Question 6

ATP role in RBCs

Answer 6

Maintains RBC shape and deformability, provides energy for active cation transport, modulates 2,3-BPG levels.

Question 7

Major glycolytic pathway in RBCs

Answer 7

Embden-Meyerhof Pathway.

Question 8

Glucose entry mechanism in RBCs

Answer 8

Via GLUT-1, no energy expenditure.

Question 9

Percentage of glucose utilization handled by Embden-Meyerhof Pathway

Answer 9

90%.

Question 10

Type of pathway EMP

Answer 10

Non-oxidative, anaerobic.

Question 11

ATP production by Embden-Meyerhof Pathway

Answer 11

Produces 2 ATP molecules.

Question 12

Inheritance pattern of PK deficiency

Answer 12

Autosomal recessive.

Question 13

Most common enzyme deficiency in EMP

Answer 13

Pyruvate kinase (PK).

Question 14

Common hereditary anemia linked to PK deficiency

Answer 14

Hereditary nonspherocytic hemolytic anemia (HNSHA).

Question 15

Peripheral blood smear findings in PK deficiency

Answer 15

Acanthocytes, Burr cells.

Question 16

Recommended screening test for PK deficiency

Answer 16

PK fluorescent spot test.

Question 17

Another screening test for PK deficiency

Answer 17

Autohemolysis test.

Question 18

Confirmatory test for PK deficiency

Answer 18

Quantitative PK assay.

Question 19

Autohemolysis pattern in PK deficiency

Answer 19

Greatly increased autohemolysis; glucose has no effect, ATP corrects hemolysis (TYPE II).

Question 20

Alternate pathways of glycolysis

Answer 20

Hexose Monophosphate Shunt, Rapoport-Luebering Shunt, Methemoglobin Reductase Pathway.

Question 21

Alternate name for Hexose Monophosphate Shunt (HMS)

Answer 21

Pentose phosphate pathway or phosphogluconate pathway.

Question 22

Primary function of HMS

Answer 22

Converts glucose to pentose and produces NADPH.

Question 23

Role of NADPH in HMS

Answer 23

Reduces glutathione.

Question 24

Function of reduced glutathione

Answer 24

Reduces peroxides, protects proteins, lipids, and heme iron from oxidation.

Question 25

HMS dependence for functionality

Answer 25

Glucose-6-phosphate dehydrogenase (G6PD).

Question 26

Purpose of HMS in globulin maintenance

Answer 26

Prevents denaturation by oxidation.

Question 27

Disorder inheritance of G6PD deficiency

Answer 27

X-linked recessive.

Question 28

Most common enzyme deficiency globally

Answer 28

Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Question 29

PBS findings in G6PD deficiency

Answer 29

Heinz bodies, Bite cells.

Question 30

Screening tests for G6PD deficiency

Answer 30

G6PD fluorescent spot test, Autohemolysis test.

Question 31

Confirmatory test for G6PD deficiency

Answer 31

Quantitative G6PD test.

Question 32

Autohemolysis pattern in G6PD deficiency

Answer 32

Slight to moderate increase, partially corrected by glucose (Type I).

Question 33

WHO Class I G6PD deficiency enzyme activity

Answer 33

Severely deficient (<1% or not detectable).

Question 34

Clinical manifestation of Class I G6PD deficiency

Answer 34

Chronic hereditary nonspherocytic hemolytic anemia (HNSHA).

Question 35

Examples of Class I G6PD variants

Answer 35

G6PD-Serres, G6PD-Madrid.

Question 36

WHO Class II G6PD deficiency enzyme activity

Answer 36

Severely deficient (<10% activity).

Question 37

Clinical manifestation of Class II G6PD deficiency

Answer 37

Severe, episodic acute hemolytic anemia associated with infections, certain drugs, and fava beans; not self-limited and may require transfusions during hemolytic episodes.

Question 38

Examples of Class II G6PD variants

Answer 38

G6PD-Mediterranean, G6PD-Chatham.

Question 39

WHO Class III G6PD deficiency enzyme activity

Answer 39

Mild to moderately deficient (10% to 60% activity).

Question 40

Clinical manifestation of Class III G6PD deficiency

Answer 40

Episodic, acute hemolytic anemia associated with infections and certain drugs; self-limited.

Question 41

Examples of Class III G6PD variants

Answer 41

G6PD-A-, G6PD-Canton.

Question 42

WHO Class IV G6PD deficiency enzyme activity

Answer 42

Mildly deficient to normal (60% to 150% activity).

Question 43

Clinical manifestation of Class IV G6PD deficiency

Answer 43

None.

Question 44

Examples of Class IV G6PD variants

Answer 44

G6PD-B (wildtype), G6PD-A+ (may also manifest as Class III).

Question 45

WHO Class V G6PD deficiency enzyme activity

Answer 45

Increased (>150% activity).

Question 46

Clinical manifestation of Class V G6PD deficiency

Answer 46

None.

Question 47

Examples of drugs causing hemolysis in G6PD deficiency

Answer 47

Dapsone, Methylthioninium chloride (methylene blue), Nitrofurantoin, Phenazopyridine, Primaquine, Rasburicase, Tolonium chloride (toluidine blue).

Question 48

Examples of chemicals causing hemolysis in G6PD deficiency

Answer 48

Aniline dyes, Naphthalene (mothballs).

Question 49

Foods that may cause hemolysis in G6PD deficiency

Answer 49

Fava beans, Red wine, Legumes (garbanzos, kadyos, munggo), Blueberry, Soya food (taho, tokwa, soy sauce), Ampalaya (bitter gourd).

Question 50

Common household items to avoid in G6PD deficiency

Answer 50

Menthol (Efficascent Oil, Listerine mouthwash).

Question 51

Frequently encountered enzymopathies

Answer 51

G6PD deficiency, Pyruvate kinase deficiency.

Question 52

Other RBC enzymopathies

Answer 52

Rare.

Question 53

Methemoglobin Reductase Pathway enzyme

Answer 53

Cytochrome b5 reductase.

Question 54

Function of cytochrome b5 reductase

Answer 54

Maintain iron in the heme in its reduced state (Fe+2).

Question 55

Rapoport-Luebering Shunt enzyme

Answer 55

2,3-BPG.

Question 56

Function of 2,3-BPG

Answer 56

Binds to hemoglobin and decreases its oxygen affinity.

Question 57

Factors affecting oxygen dissociation from hemoglobin

Answer 57

Partial pressure of oxygen, Affinity of hemoglobin for oxygen.

Question 58

Factors affecting hemoglobin affinity for oxygen

Answer 58

pH, Partial pressure of carbon dioxide, Concentration of 2,3-BPG, Temperature, Presence of other nonfunctional hemoglobin species.

Question 59

What does the Oxygen Dissociation Curve represent?

Answer 59

The relationship between oxygen saturation of hemoglobin and the partial pressure of oxygen, plotted on a graph.

Question 60

Increased affinity (Shift to the left)

Answer 60

Increased pH, decreased PCO2, decreased 2,3-BPG, decreased temperature.

Question 61

Decreased affinity (Shift to the right)

Answer 61

Decreased pH, increased PCO2, increased 2,3-BPG, increased temperature.

Question 62

Bohr effect

Answer 62

A shift in the curve due to an alteration in pH (or hydrogen ion concentration) and the effect of hydrogen ions and CO2 on the affinity of hemoglobin for oxygen.

Question 63

Haldane effect

Answer 63

Occurrence where the binding of O2 to hemoglobin promotes the release of CO2.