THE HEMOGLOBIN DETERMINATION: (THE CYANMETHEMOGLOBIN METHOD)

Oxyhemoglobin

Measures hemoglobin

indirect measures of oxyhemoglobin

 acid hematin, cyanmethemoglobin, alkali hematin, and carboxyhemoglobin.

Drabkin's reagent

• is used to measure hemoglobin through the cyanmethemoglobin method.

• It consists of sodium bicarbonate, potassium cyanide, and potassium ferricyanide.

ferricyanide

converts the iron in the hemoglobin

molecule from the ferrous to ferric state, forming methemoglobin or

hemiglobin or ferrihemiglobin. The product then combines with potassium

cyanide to produce cyanmethemoglobin or hemoglobin cyanide.

cyanmethemoglobin method

the best method for manual hemoglobin

determination because all forms of hemoglobin are converted to

cyanmethemoglobin except sulfhemoglobin. The procedure uses a very stable

standard.

sulfhemoglobin

no measured in cyanmethemoglobin

120-160 g/L

Reference values of Women in Cyanmethemoglobin120-160 g/

140-180 g/L

Reference values of men in Cyanmethemoglobin

85-140 g/L

Reference values of Women in late preganncy in Cyanmethemoglobin

140-250 g/L

Reference values of Children in Cyanmethemoglobin

Increased (hyperchromia)

in polycythemia, dehydration, in poorly compensated

heart disease with cyanosis, and in changing from lowto high altitude.

Decreased (oligochromia)

anemias

Hemoglobinemia

• severe infection;

• b. severe burns and frost bite;

• c. poisoning with potassium chlorate and mushrooms;

• d. paroxysmal hemoglobinuria;

• e. hemolytic transfusion reactions

PACKED CELL VOLUME

• The packed cell volume or the hematocrit of a sample of blood is the ratio of the volume of erythrocytes to that of the whole blood.

• It is expressed as a percentage or preferably, as a decimal fraction.

• often referred to as volume percent erythrocytes or volume of packed red cells.

• This test is considered to be the most sensitive test when excess of anticoagulant is used during blood collection.

venous hematocrit.

measures the proportion of red blood cells to plasma in the peripheral blood, but not in the entire circulation.

body hematocrit.

The ratio of the total erythrocyte mass to the total blood volume

 importance of hematocrit determination

gives a rough estimate of the

size of erythrocytes and the concentration of erythrocytes but not the whole red cell

mass. It can be used to calculate red cell indices.

buffy coat 

creening test for anemia. Since the inherent error obtained in hematocrit is less

compared to erythrocyte count in CBC.

 packed cell volume (PCV)

measurement of the ratio of the volume occupied by the RBCs to the volume of whole blood in a sample of capillary or venous blood. Following centrifugation, this ratio is measured and expressed as a percentage or decimal fraction.

packed cell volume (PCV)

used to detect anemia, polycythemia, hemodilution, or

hemoconcentration. In conjunction with an erythrocyte count, the PCV is used to calculate

the mean corpuscular volume (MCV). The PCV is also used in conjunction with the

hemoglobin concentration to calculate the mean corpuscular hemoglobin concentration

(MCHC).

MACROMETHOD

• Wintrobe Method

Double Oxalate

Anticoag in wintrobe method

MICROMETHOD

Adam’s Method

Adam’s method

This method uses heparinized capillary hematocrit tube of about 7 cm. long and an internal diameter of 1.0 mm.

Heparinized (red) capilette

used if specimen is capillary blood

Blue capilettes

used in the case of venous blood

40-54

PCV Ref in Men

37-47

pcv ref in women

44-64

PCV Ref in Newborn

mcv and mch formula 

hct x 10/RBC

mchc formula

hgb x 100 hct

rdw formula

sd of mcv/mch x 100

normal range of mcv

81-100 fL

normal range of mch

23-34 pg

normal range of mchc

31-36%

normal range of rdw

11.5-14.5%

Increased in MCV

1. pernicious anemia

2. folic acid def

3. antimetabolite anemia 

4. chronic liver disease

5. Alcoholism

decrease in MCV

1. ida 

2. thalassemia 

3. chronic disease

Increased in MCH

1. macrocytic anemia

2. newborn 

decrease in MCH

1. microcytic anemia 

2. hypochromic anemia 

Increased in MCHC

1. spherocytosis 

2. newborn

decrease in MCHC

1. ida

2. thalassemia

3. microcytic anemia with chronic blood loss