What is the diluent used in the cyanmethemoglobin method for the determination of hemoglobin?

The cyanmethemoglobin method for the determination of hemoglobin employs Drabkin's solution as its diluent. This solution is critical because it contains potassium ferricyanide and potassium cyanide, which react with hemoglobin to form cyanmethemoglobin, a stable derivative that can be measured spectrophotometrically. This method is widely used due to its accuracy and ability to quantify total hemoglobin levels in a blood sample.

In contrast, normal saline primarily serves as a general fluid replacement and does not facilitate the chemical reactions needed for hemoglobin determination. Sodium citrate acts as an anticoagulant and is often used in blood collection but does not participate in the colorimetric analysis required for this hemoglobin measurement. Phosphate buffer provides a stable pH environment for various biochemical reactions but is not specifically designed for the cyanmethemoglobin reaction. Thus, Drabkin's solution is specifically formulated to enable the accurate determination of hemoglobin levels through its chemical interactions.