OSMOTIC FRAGILITY TEST

Question 1

what is the principle behind the OFT

Answer 1

The osmotic fragility test is a measure of the ability of the red cells to take up fluid without lysing

The whole blood is added to varying concentrations of sodium chloride solution and allowed to incubate at room temperature. The rate of hemolysis is then determined through visual inspection of each saline concentration.

Question 2

temperature we incubate the sample for oft

Answer 2

room temperature

Question 3

what solution we are using for oft in which the blood we are testing is added?

Answer 3

sodium chloride solution

Question 4

. The rate of hemolysis is then determined through CHEMICAL INSPECTION of each saline concentration.

True or false

Answer 4

false- visual inspection

Question 5

the relative concentration of solutes dissolved in a solution which DETERMINE THE DIRECTION AND EXTENT OF DIFFUSION

Answer 5

tonicity

Question 6

3 classification of tonicity

Answer 6

isotonic
hypotonic
hypertonic

Question 7

a classification of tonicity in which
the solution has the same number of solute particles as the cell

Answer 7

isotonic

Question 8

a classification of tonicity in which
the solution has fewer solute particles per liter of solution

Answer 8

hypotonic

Question 9

a classification of tonicity in which
the solution with higher solute particles per liter of solution

Answer 9

hypertonic

Question 10

a hypotonic solution will result to a __ of a cell

(swelling, shrinking)

Answer 10

swelling

Question 11

a hypertonic solution will result to a __ of a cell

(swelling, shrinking)

Answer 11

shrinking

Question 12

is a transport of water to a higher concentration of solute

Answer 12

osmosis

Question 13

2 terms we need to consider in osmosis

Answer 13

concentration and tonicity

Question 14

what is the difference between concentration and tonicity

Answer 14

tonicity - the difference of concentration into environment
concentration - the amount of solute

Question 15

is the one responsible for the integrity and stability of the cell.

It as well controls the in and out of the cell.

Answer 15

plasma membrane

Question 16

red cell with peripheral rim of hemoglobin surrounded by clear area and central hemoglobinized area

Answer 16

Target cell/Codocyte/Mexican hat cell

Question 17

small, round, dense red blood cells with no central pallor

Answer 17

spherocytes

Question 18

significance of OFT test

Answer 18

This test is employed to diagnose conditions in which the PHYSICAL PROPERTIES OF THE CELL ARE ALTERED

Question 19

The _____ of the red blood cells is the primary factor affecting the osmotic fragility test

Answer 19

shape

Question 20

OFT depends on which properties of rbc plasma membrane?

Answer 20

volume, surface area and functional state of the red blood cell membrane

Question 21

. The larger the amount of surface area of the red cell membrane, the more fluid the cell is capable of absorbing before rupturing ( low OFT), and is usually observed in __ cells.

(target cell, spherocytes)

Answer 21

target cell

Question 22

the spherocyte has the smallest surface area for its volume and ruptures more quickly which means it has (higher, lower) OFT

Answer 22

higher

Question 23

diseases which we can found increase oft

Answer 23

hemolytic anemias and hereditary spherocytosis, older rbc.

Question 24

decrease OFT are seen in what diseases

Answer 24

sickle cell anemia, iron-deficiency anemia, thalassemia, polycythemia and conditions where target cells are present, reticulocytes

Question 25

materials used in OFT

Answer 25

• 12 test tubes
• Test tube rack
• 0.5% NaCl
• Distilled water
• Sahli pipette
• Heparinized blood
• Dropper

Question 26

formula used in OFT

Answer 26

number of tube multiplied by the amount of blood (0.02 ml)

Question 27

how many hours do we need to incubate the sample?

Answer 27

2 hrs - (we did it for only 1 hr)

Question 28

how many minutes we do need to centrifuge the sample

Answer 28

5 mns

Question 29

which tube do we need to start checking for initial hemolysis?

Answer 29

test tube #25

Question 30

a stage where in a tinge of pinkness in the supernatant and some cells at the bottom of the tube are observed

Answer 30

initial hemolysis

Question 31

a stage wherein clear, red supernatant with no microscopic cells at the bottom of the tube are observed

Answer 31

complete hemolysis

Question 32

reference value or tube for initial hemolysis

Answer 32

0.42-0.44% (Test tube #21 or 22)

Question 33

reference value or the number for complete hemolysis

Answer 33

0.32-0.34% (Test tube #16 or 17)

Question 34

relationship of the test tube number and the hypotonicity of the solution

Answer 34

inversely proportional