OFT

Question 1

_______are surrounded by a _______that allows the_________and______

If the RBCs are placed in a _________, _______will be established by _______ into the ____which then_____

Answer 1

Red blood cells

Selectively permeable membrane

Exchange of gases and electrolytes

Hypotonic solution

Osmotic equilibrium

Drawing blood

Cells

Swell

Question 2

Increased permeability of RBC membrane leads to the accumulation of______within the cell and finally the escape of ______ through the______ of cell membrane

Answer 2

Water

Hemoglobin

Widened pores

Question 3

Used for definitive diagnosis or traditional screening test of___________in combination with other test such as _____

Test that demonstrate _________

RBCs that have decreased surface area -to-volume ratio is_______

Answer 3

Hereditary spherocytosis

Blood indices

Increases RBC fragility

Spherocytosis

Question 4

Causes of decreased surface area-to-volume ratio (2)

Answer 4

Hereditary spherocytosis

Warm autoimmune hemolytic anemia

Question 5

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

Answer 5

Hereditary spherocytosis

Question 6

RBCs are sensitized by antibodies known as IgGs that are pitted in spleen resulting in spherocute formation

Answer 6

Warm autoimmune hemolytic anemia

Question 7

OFT lacks ____and_____ because it cannot differentiate wheter the cause of spherocyte formation is due to HS or
WAHA

Answer 7

Specificity

Sensitivity

Question 8

OFT PRINCIPLE

Whole blood is added to varying concentrations of _______ that being_________and allowed to incubate at ________

Answer 8

Hypotonic solution

Buffered sodium chloride solution

Room temp

Question 9

PRECAUTIONS IN PERFORMING OFT

Blood sample should be obtained with______and ______

Test should be _________

Sizes of drops of blood must be _____

Blood should fall directly into the ________and not on the______of tubes

Answer 9

Minimum stasis and trauma

Set up as soon as possible

Uniform

Saline solution ; sides

Question 10

SPECIMEN USED FOR OFT

Answer 10

Fresh heparinized blood

Question 11

Name of tubes:

Numbers of tubes used:

Answer 11

Wassermann tubes

12

Question 12

Rejection criteria:

Answer 12

Hemolyzed specimen

Question 13

Method used for OFT

Answer 13

Griffin-sandford method

Question 14

PROCEDURE

0.5g NaCI dissolved in ______

Arrange 12 wassermann tubes and label tubes from_____ (left to right)

Number of drops should correspond to _________

Add _______

Deliver a drop of _______into each tube mix_____

Allow tubes to stand for ____at________

Examine the tube for ____and_______

Answer 14

100 mL of distilled water

25 down to 14

Number of each tube

Distilled water

Freshly drawn blood

Gently

2 hours at room temp

Initial and complete hemolysis

Question 15

Formula of griffin-sandford method

Answer 15

Tube number x 0.02=%

Question 16

INITIAL HEMOLYSIS

Hemolysis is partial if the fluid turns _______

_____or______still present

Starts at _______ in normal biconcave RBCs

No hemolysis yet in test tubes ___,___,__

Answer 16

Faintly pink

Sediment red cells or cell buttom

22 & 21

25, 24, 23

Question 17

COMPLETE HEMOLYSIS

Complete when the fluid turns _____with_____

_____and_____not present

Starts at test tubes _____&____

Answer 17

Red with no sediments

Sediment red cell or cell bottom

16 & 17

Question 18

NORMAL VALUES

Initial hemolysis:

Complete hemolysis:

Answer 18

0.42-0.44%

0.32-0.34%

Question 19

ERYTHROCYTE OSMOTIC FRAGILITY CURVE

A: (4)
B:
C: (2)

Answer 19

Decreased OFT / shift to the right
Thalassemia, Hemoglobinopathies, Target cells, Reticulocytes

Normal biconcave RBC

Increased OFT / shift to the left
Spherocytosis & older red cells

Question 20

FACTORS THAT AFFECT OFT

_____of red cells

______of cell membrane

______to_____area

________ of sodium chloride

_____ of sodium chloride solution

_______of solution

pH must be _____a chamge of pH by _____is equal to cganges of tonicity by___

A temperature rise will _____,___C
Change is equal to a change of tonicity of about____

Answer 20

Shape

Functional state

Surface-to-volume area

Chemical purity

Accuracy

Tonicity

7.4 ; 0.1% ; 0.01%

Increase fragility ( 5 ; 0.01% )

Question 21

INCREASED OSMOTIC FRAGILITY (4)

Answer 21

Decreased resistance

Hemolytic anemia

Hereditary spherocytosis

Whenever spherocytes are found

Question 22

DECREASED OSMOTIC FRAGILITY (8)

Answer 22

Inc resistance

Splenectomy

Liver disease

Sickle cell anemis

Iron deficiency anemia

Thalassemia

Polycythemia vera

Conditions in whic target cells are present