OFT

Question 1

RBCs placed in Hypotonic Solution causes them to?

Answer 1

Swell

Question 2

What leades to accumulation of water in RBCs?

Answer 2

Increased Permeability

Question 3

OFT is a screening test for?

Answer 3

Hereditary Spherocytosis

Question 4

Test that demonstrates increased RBC Fragility

Answer 4

OFT

Question 5

RBCs that have Decreased Surface Area to Volume Ratio?

Answer 5

Spherocytes

Question 6

This is Caused by lack of vertical interaction of RBC Membrane which is a result of ______

Answer 6

Hereditary Spherocytosis/ Spectrin Deficiency

Question 7

In WAHA, RBCs are sensitized by antibodies known as _____

Answer 7

IgGs

Question 8

OFT lacks ____ and ____ because it cannot differentiate HS or WAHA

Answer 8

Specificity and Sensitivity

Question 9

Principle of OFT

Answer 9

Whole Blood is added to hypotonic solutions that being buffered sodium chloride solution and allow to incubate at RT

Question 10

4 Precautions of OFT

Answer 10

1. Sample with Minimum Stasis and Trauma
2. Test should be set ASAP
3. Uniform Size of drops
4. Blood should fall directly into saline solution

Question 11

Tube used for OFT?

Answer 11

Heparin (Green)

Question 12

Hypotonic Solution Used?

Answer 12

0.5% NaCl

Question 13

Rejection Criteria for OFT?

Answer 13

Hemolyzed Specimen

Question 14

0.5% NaCl Solution consist of? (2)

Answer 14

0.5g NaCl in 100ml D Water

Question 15

Name of 12 tubes used for OFT?

Answer 15

Wasserman

Question 16

How long do you stand the tubes for?

Answer 16

2 Hours

Question 17

Method used for OFT?

Answer 17

Griffin-Sandford Method

Question 18

Computation for Griffin-Sandford Method

Answer 18

Tube # x 0.02

Question 19

Color of Initial Hemolysis

Answer 19

Pink

Question 20

Color of Complete Hemolysis

Answer 20

Red

Question 21

Cell button is present

Answer 21

Initial Hemolysis

Question 22

Initial Hemolysis normally starts at what tubes?

Answer 22

22 & 21

Question 23

Complete Hemolysis normally starts at what tubes?

Answer 23

16 & 17

Question 24

Reference Value of Griffin-Sandford Method

Answer 24

Initial : 0.42-0.44%
Complete: 0.32-0.34%

Question 25

Shift to the Left indicates?

Answer 25

Increased OFT

Question 26

Examples of Increased OFT (2)

Answer 26

1. Spherocytes
2. Older RBCs

Question 27

Shift to the Right Indicates?

Answer 27

Decreased OFT

Question 28

Examples of Decreased OFT? (3)

Answer 28

1. Thalassemia
2. Hemoglobinopathies
3. Reticulocytes

Question 29

8 Factors that affect OFT

Answer 29

1. Shape
2. Functional State
3. Surface to Volume Area
4. Chemical Purity
5. Accuracy of NaCl
6. Tonicity of Solution
7. pH
8. Temperature

Question 30

in OFT, pH level must be?

Answer 30

7.4

Question 31

A change of pH by 0.1 is equal to the ______ by _____

Answer 31

Change of Tonicity by 0.01%

Question 32

5°c change is equal to a change of tonicity by?

Answer 32

0.01%

Question 33

Increased OFT indicates? (4)

Answer 33

1. Decreased Resistance
2. HA
3. HS
4. Spherocytes

Question 34

Decreased OFT Indicates? (8)

Answer 34

1. Increased Resistance
2. Splenectomy
3. Liver Disease
4. Sickle Cell Anemia
5. IDA
6. Thalassemia
7. Polycythemia Vera
8. Target Cells