OFT

Question 1

Red blood cells are surrounded by a_________ that allows the______ and_______

Answer 1

Selectively permeable membrane

Exchange of gases

Electrolytes

Question 2

If the RBC’s are placed in a_________ Osmotic equilibrium will be established by______ into cells, which then_______

Answer 2

Hypertonic saline solution

Drawing water

Swell

Question 3

Increased permeability of the RBC membrane leads to the_________ and finally the escape of hemoglobin through the______ of the cell membrane

Answer 3

Accumulation of water within the cell

Widened pores

Question 4

Used for definitive diagnosis or traditional screening test of hereditary spherocytosis in combination with other tests such as_______

Answer 4

Osmotic fragility test

Blood indices

Question 5

Test that demonstrates increased RBC fragility

Answer 5

Osmotic fragility test

Question 6

Which RBC have decreased surface area to volume ratio

Answer 6

Spherocytes

Question 7

Two causes of decreased surface area to volume

Answer 7

Hereditary spherocytosis

Warm autoimmune hemolytic anemia

Question 8

Condition caused by lack of vertical interaction of RBC membrane as a result of spectrin deficiency

Answer 8

Hereditary spherocytosis

Question 9

Condition where RBC’s are sensitized by antibodies known as IgG that are pitted in the spleen resulting in spherocyte formation

Answer 9

Warm autoimmune hemolytic anemia

Question 10

OFT lacks _______and_______ because it cannot differentiate whether the cost of piracy formation is due to HS or WAHA

Answer 10

Specificity and sensitivity

Question 11

Principle of OFT

Answer 11

Whole blood is added to varying concentrations of hypotonic solution that being buffered, sodium chloride solution and allowed to incubate at room temperature

Question 12

4 precautions in performing OFT

Answer 12

Blood sample should be obtained with minimum stasis and trauma

The test should be set up as soon as possible

The sizes of the drops of blood must be uniform

Blood should fall directly into the salineh solution and not on the sides of the tubes

Question 13

Specimen used for OFT

Answer 13

Fresh heparinized blood

Question 14

Type of test tube used in griffin- Sanford method

Answer 14

12 Wassermann tubes

Question 15

Rejection criteria for OFT

Answer 15

Hemolyzed specimen

Question 16

___sodium chloride dissolved in____ distilled water

Answer 16

0.5 grams

1000 mL

Question 17

In Griffin-Sanford method allow the tubes to stand for_______ at_____

Answer 17

2 hours

Room temperature

Question 18

Formula for griffin Sanford method

Answer 18

Tube number X 0.02= %

Question 19

Normal value of initial hemolysis

Answer 19

0.42% - 0.44%

Question 20

Normal value of complete hemolysis

Answer 20

0.32% - 0.34%

Question 21

INITIAL HEMOLYSIS OR COMPLETE HEMOLYSIS

HEMOLYSIS IS PARTIAL IF THE FLUID (SUPERNATANT ) TURNS FAINTLY PINK

Answer 21

Initial hemolysis

Question 22

INITIAL HEMOLYSIS ARE COMPLETE HEMOLYSIS

SEDIMENT RED CELLS OR CELL BUTTON STILL PRESENT

Answer 22

Initial hemolysis

Question 23

INITIAL HEMOLYSIS ARE COMPLETE HEMOLYSIS

STARTS AT THE TEST TUBES 22, 21 IN NORMAL BICONCAVE RBCs

Answer 23

Initial hemolysis

Question 23

INITIAL HEMOLYSIS ARE COMPLETE HEMOLYSIS

NO HEMOLYSIS YET IN TEST TUBE 25, 24, 23

Answer 23

Both initial hemolysis and complete hemolysis

Question 24

INITIAL HEMOLYSIS ARE COMPLETE HEMOLYSIS COMPLETE WHEN THE FLUID (SUPERNATANT) IS RED WITH NO SEDIMENTS

Answer 24

Complete hemolysis

Question 25

INITIAL HEMOLYSIS OR COMPLETE HEMOLYSIS SEDIMENT OR RED CELL BUTTON IS NOT PRESENTH

Answer 25

Complete hemolysis

Question 26

INITIAL HEMOLYSIS OR COMPLETE HEMOLYSIS Starts at test tubes 16, 17 in normal biconcave RBC

Answer 26

Complete hemolysis

Question 27

3 erythrocyte osmotic fragility curve

Answer 27

B C A

Question 28

B stands for

Answer 28

Normal biconcave RBC

Question 29

C stands for 2 conditions:

Answer 29

Increased OFT or shift to the left Spherocytosis Older red cells

Question 30

A stands for 4 conditions:

Answer 30

Decreased OFT or shift to the right Thalassemia Hemoglobinopathies Target cells Reticulocytes

Question 31

8 factors that affect OFT

Answer 31

Shape of red cells Functional state of cell membrane Surface to volume area Chemical purity of sodium chloride Accuracy of sodium chloride solution Tonicity of solution pH must be 7.4 (a change of pH by 0.1 is equal to the change of tonicity by 0.01%) A temperature rise will increase fragility (5°C change is equal to a change of tonicity about 0.01%)

Question 32

INCREASED OR DECREASED OFT Why? Decreased resistance

Answer 32

Increased Due to decreased surface to volume ratio

Question 33

INCREASED OR DECREASED OFT WHY? Hemolytic anemias

Answer 33

RBCs have defective membranes

Question 34

Increased or decreased OFT Why? Hereditary spherocytosis

Answer 34

Increased Due to defected RBCs

Question 35

Increased or decreased OFT Why? Increased resistance

Answer 35

Decreased Due to higher surface area to volume

Question 36

Increased or decreased OFT Why Splenectomy

Answer 36

Decreased Due to greater long-term risks

Question 37

Increased or decreased OFT Why Sickle cell anemia

Answer 37

Decreased Due to structural changes

Question 38

Increased or decreased OFT Why Iron deficiency anemia

Answer 38

Decreased

Question 39

Increased or decreased OFT Why Thalassemia and polycythemia Vera

Answer 39

Decreased Due to RBC’s are altered