MODULE 5 UNIT 2: OSMOTIC FRAGILITY TEST

Question 1

A standard volume of fresh, heparinized blood is mixed with NaCl solutions ranging from [?] (isotonic saline) to 0.0% (distilled water) in 0.05% to 0.1% increments. After a 30-minute incubation at room temperature, the tubes are centrifuged and the absorbance of the supernatant is measured spectrophotometrically at 540 nm.

Answer 1

0.85%

Question 2

A standard volume of fresh, heparinized blood is mixed with NaCl solutions ranging from 0.85% (isotonic saline) to [?] (distilled water) in 0.05% to 0.1% increments. After a 30-minute incubation at room temperature, the tubes are centrifuged and the absorbance of the supernatant is measured spectrophotometrically at 540 nm.

Answer 2

0.0%

Question 3

A standard volume of fresh, heparinized blood is mixed with NaCl solutions ranging from 0.85% (isotonic saline) to 0.0% (distilled water) in (?) to 0.1% increments. After a 30-minute incubation at room temperature, the tubes are centrifuged and the absorbance of the supernatant is measured spectrophotometrically at 540 nm.

Answer 3

0.05%

Question 4

A standard volume of fresh, heparinized blood is mixed with NaCl solutions ranging from 0.85% (isotonic saline) to 0.0% (distilled water) in 0.05% to 0.1% increments. After a (?) at room temperature, the tubes are centrifuged and the absorbance of the supernatant is measured spectrophotometrically at 540 nm.

Answer 4

30-minute incubation

Question 5

A standard volume of fresh, heparinized blood is mixed with NaCl solutions ranging from 0.85% (isotonic saline) to 0.0% (distilled water) in 0.05% to 0.1% increments. After a 30-minute incubation at room temperature, the tubes are centrifuged and the absorbance of the supernatant is measured spectrophotometrically at (?).

Answer 5

540 nm

Question 6

(?) is the absorbance in the tube to be measured

Answer 6

Ax%

Question 7

(?) is the absorbance in the A0.85% NaCl tube (representing 0% hemolysis)

Answer 7

A0.85%

Question 8

(?) is the absorbance

Answer 8

A0.0%

Question 9

The % (?) for each % NaCl concentration will be plotted, and an osmotic fragility curve is to be drawn

Answer 9

hemolysis

Question 10

(?) show initial hemolysis at 0.45% NaCl

Answer 10

Normal biconcave RBCs

Question 11

100% or complete hemolysis generally occurs between (?) NaCl

Answer 11

0.35% and 0.30%

Question 12

initial hemolysis begins at an NaCl concentration greater than (?).

Answer 12

0.5%

Question 13

If the curve is shifted to the (?), the patient’s RBCs have increased osmotic fragility.

Answer 13

left

Question 14

If the curve is shifted to the (?), the RBCs have decreased osmotic fragility.

Answer 14

right

Question 15

(?) is found in conditions characterized by numerous target cells, such as thalassemia.

Question 16

Incubating the blood at (?) before performing the test (called the incubated osmotic fragility test) allows HS cells to become more spherical and is often needed to detect mild cases.

Answer 16

37°C for 24 hours

Question 17

Patients who have (?) is incubated tend to have mild disease and a low number of spherocytes in the total RBC population.

Answer 17

increased osmotic fragility only when their blood

Question 18

Griffin and Sanford Method

Answer 18

Counting chamber

Question 19

Principle
o 12 test tubes are prepared and each tube are numbered from 25 to 14.
o Each tube must contain a specific NaCl concentration (%NaCl= tube number X 0.02) and a drop from an EDTA treated whole blood. o Except tube 25, the amount of distilled water to be added in each tube containing the drop of whole blood and specific concentrations of NaCl are listed in the table.
o This will test the stability of the red blood cells under different concentrations of NaCl.
o As the amount of distilled water in each tube increases, this makes the solution more hypotonic.

Answer 19

Griffin and Sanford Method

Question 20

: tubes with compact sediments and clear solution

Answer 20

No Hemolysis

Question 21

: first tube from the left (tube 25) with not so compact sediments and with faint solution

Answer 21

Initial Hemolysis (IH)

Question 22

: first tube from the left (tube 25) without sediments and with dark red solution

Answer 22

Complete Hemolysis (CH)

Question 23

Result Interpretation
Normal Values:
o Initial Hemolysis: tube (?)
o Complete Hemolysis: (?)

Answer 23

o Initial Hemolysis: tube 22 (.42 - .44% NaCl)
o Complete Hemolysis: tube 17 (.32 - .34% NaCl)

Question 24

This test demonstrates the increase fragility of erythrocytes in blood specimens in which the surface area to volume ratios of the erythrocytes has decreased. A series of tubes with increasingly hypotonic sodium chloride (NaCl) solutions will be added with blood.

Answer 24

Griffin and Sanford Method

Question 25

In each tube, water enters and leaves the (?) until equilibrium is achieved.

Answer 25

RBCs

Question 26

In (?) NaCl, the amount of water entering the cell is equivalent to the water leaving the cell because the intracellular and extracellular osmolarity is the same.

Answer 26

0.85%

Question 27

In a (?), more water will enter the cell to dilute the intracellular contents until equilibrium is reached between the cytoplasm and the hypotonic extracellular solution.

Answer 27

hypotonic solution

Question 28

Griffin and Sanford Method
As this phenomenon occurs, the (?) swell.

Answer 28

cells

Question 29

As the (?) are subjected to increasingly hypotonic solutions, even more water will enter the (?) until the internal volume is too great and lysis occurs.

Answer 29

RBCs

Question 30

Because (?) already have a decreased surface area to volume ratio, they lyse in less hypotonic solutions than normalshaped, biconcave RBCs and thus have increased osmotic fragility.

Answer 30

spherocytes

Question 31

The osmotic fragility test is time-consuming as it requires a blood specimen collected fresh with heparin as its anticoagulant without trauma and NaCl solutions should be made accurately

Question 32

At room temperature Specimens are stable for 2 hours. However, if refrigerated, specimen is viable for 6 hours

Question 33

The osmotic fragility test is also non-specific and an increased fragility does not differentiate spherocytosis caused by other conditions, such as burns, immune hemolytic anemias, and other acquired disorders