b. Discussion.
(1) Cyanmethemoglobin is the most stable of the various hemoglobin
The availability of prepared standards is a distinct advantage of this technique. All
hemoglobin derivatives are converted to cyanmethemoglobin with the exception of
sulfhemoglobin.
(2) This method is highly accurate and is the most direct analysis available
for total hemin or hemoglobin iron. Its disadvantage is the use of cyanide compounds,
which, if handled carefully, should present little hazard.
(3) For accuracy in hemoglobin determinations, it is absolutely necessary
that the spectrophotometer and Sahli pipets be accurately calibrated.
(4)
Venous samples give more constant values than capillary samples.
(5)
If the procedure is performed properly, the degree of accuracy is +2 to 3
percent.
c. Normal Values.
(1)
Infants at birth: 1723 g hemoglobin per deciliter.
(2)
Childhood: 1214 g hemoglobin per deciliter.
(3)
Adult males: 1417 g hemoglobin per deciliter.
(4)
Adult females: 1315 g hemoglobin per deciliter.
6-11. DETECTION OF HEMOGLOBIN S AND NON S SICKLING HEMOGLOBINS
a. Principle. Erythrocytes are introduced into a phosphate buffer solution
containing a reducing agent and hytic agent. The red cells are lysed and the
hemoglobin is reduced. Reduced sickling types of hemoglobin are insoluble in
phosphate buffer and turbidity results. On addition of urea, hemoglobin S dissolves.
b. Reagents.
(1) Stock phosphate buffer solution. Dissolve 160.48 grams anhydrous
potassium dihydrogen phosphate (KH2PO4), AR, and 28.88 grams anhydrous
potassium monohydrogen phosphate (K2HPO4) and AR in a 1-liter volumetric flask
containing 500 ml of distilled water. Dilute to 1-liter with distilled water.
(2) Dithionite reagent. Add 20.0 grams dithionite (Ha2S404 2H20) and 0.25
grams saponin to a 100-ml volumetric flask. Add 80 ml of stock phosphate buffer
MD0853
6-9