... specimens should be frozen [9, 10] . At 3° C of storage, a slight liberation of CO can occur [10] ; at –30° C, slight production of Met-Hb is obtained, but no changes in values of COHb and the total ... [11]): 20 g of potassium ferricyanide is dis-solved in 500 mL of 1/15 M phosphate bu er solution (pH 7.1), followed by the addition of 50 mg potassium cyanide and 100 mL of 1% Triton X -100 (obtainable ... blank test. e total Hb concentration of the test blood is easily calcu-lated by comparing the absorbance of the test blood with that of the standard solution of cyanmethemogloblin included in...