Cyanmethemoglobin

Question 1

The cyanmethemoglobin is said to be the method of choice for hemoglobin determination because:

Answer 1

1. Cyanmethemoglobin is stable in dilutions.
2. Cyanmethemoglobin standard are readily available.
3. All hemoglobin derivatives except sulfhemoglobin are measured with their conversion to cyanmethemoglobin.

Question 2

Principle of Cyanmethemoglobin Method:

Answer 2

• Hemoglobin iron is converted from ferrous to ferric state to form methemoglobin by the action of ferricyanide.
• Methemoglobin then combines with potassium cyanide to produce the stable cyanmethemoglobin which is measured spectrophotometrically.

Question 3

Complete the statement:

Hemoglobin iron is converted from _____ to _____ state to form methemoglobin by the action of ferricyanide.

Answer 3

Ferrous
Ferric

Question 4

Complete the Statement:

Hemoglobin iron is converted from ferrous to ferric state to form _____ by the action of _____.

Answer 4

Methemoglobin
Ferricyanide

Question 5

Complete the statement:

_____ then combines with potassium cyanide to produce the stable cyanmethemoglobin which is measured spectrophotometrically.

Answer 5

Methomoglobin

Question 6

Complete the statement:

Methemoglobin then combines with _____ to produce the stable cyanmethemoglobin which is measured spectrophotometrically.

Answer 6

Potassium cyanide

Question 7

Complete the statement:

Methemoglobin then combines with potassium cyanide to produce the stable _____ which is measured spectrophotometrically.

Answer 7

Cyanmethemoglobin

Question 8

Patient Preparation:

Answer 8

1. Explain the test purpose.
2. If your blood sample is being tested only for hemoglobin, you can eat and drink normally before the test.

Question 9

Materials needed:

Answer 9

Anticoagulated blood
Test tubes
Pipette
Spectrophotometer
Drabkin’s reagent
Cuvette

Question 10

Write down the step-by-step procedure in the Cyanmethemoglobin Determination:

Answer 10

1. Place 5 ml of Drabkin’s reagent into a test tube.
2. Using Sahli pipette, draw blood to 0.02 cc mark. Make sure to wipe the outer wall of the pipette, and then dispense the blood to the test tube.
3. Gently draw up and down to rinse the pipette and also to mix the resulting colloidal suspension.
4. Cover and mix well by inversion. Let it stand for 5 minutes.
5. Transfer the mixture to a cuvette.
6. Set the spectro to 100% transmittance at the wavelength of 540 nm. Using a cyanmethemoglobin reagent blank.
7. Continue reading the patient’s sample and record the percentage transmittance.

Question 11

How many ml of Drabkin’s reagent is transferred into the test tube?

Answer 11

5ml of Drabkin’s reagent

Question 12

How many cc of blood is needed to be transferred to the test tube with Drabkin’s reagent?

Answer 12

0.02cc of blood

Question 13

After we cover and mix the solution of Drabkin’s reagent and blood into the test tube, we let the solution stand for how many minutes?

Answer 13

5 minutes

Question 14

Complete the statement:

We set the spectrophotometer into _____ transmittance at the wavelength of _____.

Answer 14

100%
540 nm

Question 15

Formula to get the Abs:

Answer 15

Abs = 2-log (%T)

Question 16

Formula for the Conc of Unknown:

Answer 16

Conc of Unknown: (abs of unknown/abs of std) x value of std

Question 17

Reference value for Male:

Answer 17

13.5 - 18.0 g/L

Question 18

Reference value for Female:

Answer 18

12 - 15 g/L

Question 19

Clinical Implications:

Answer 19

1. Decreased Hgb levels are found in
   Anemia.
2. Increased Hgb levels are found in: Polycythemia vera, congestive heart failure, and chronic obstructive pulmonary disease.

Question 20

Complete the Statement:

Decreased Hgb levels are found in _____.

Answer 20

Anemia

Question 21

Complete the Statement:

Increased Hgb levels are found in _____, _____, and _____

Answer 21

PV
CHF
COPD

Question 22

Sources of Errors:

Answer 22

1. Errors inherent in the sample:
   a. Blood sample collected through improper venipuncture
   b. Blood sample collected through improper skin or capillary puncture technique.
2. Errors inherent in the method.
3. Errors inherent in the equipment:
   a. The accuracy of the equipment is not uniform
   b. Unmatched cuvettes
   c. Improper standardization of the photometer or colorimeter
4. Operator’s error – human errors

Question 23

Human errors can be reduced by:

Answer 23

• Understanding the clinical significance of the test and the necessity for a dependable method
• Adherence to oral and written instructions
• Familiarity with the equipment and with the sources of error

Question 24

Identify what Step Number:

Place 5 ml of Drabkin’s reagent into a test tube.

Answer 24

Step 1

Question 25

Identify what Step Number: Using Sahli pipette, draw blood to 0.02 cc mark. Make sure to wipe the outer wall of the pipette, and then dispense the blood to the test tube.

Answer 25

Step 2

Question 26

Identify what Step Number: Gently draw up and down to rinse the pipette and also to mix the resulting colloidal suspension.

Answer 26

Step 3

Question 27

Identify what Step Number: Cover and mix well by inversion. Let it stand for 5 minutes.

Answer 27

Step 4

Question 28

Identify what Step Number: Transfer the mixture to a cuvette.

Answer 28

Step 5

Question 29

Identify what Step Number: Set the spectro to 100% transmittance at the wavelength of 540 nm. Using a cyanmethemoglobin reagent blank.

Answer 29

Step 6

Question 30

Identify what Step Number: Continue reading the patient’s sample and record the percentage transmittance.

Answer 30

Step 7