International Committee for Standardization in Hematology

I. Material for Serum-lron Reference Preparation1.1.The material should consist of sterile pooled human sera obtained from normal subjects, taken and handled at all steps of processing with sterile techniques.1.2.At present, it appears that horse serum may be substituted for human serum.1.3.The haemoglobin concentration of the serum pool should not exceed 3 mg/Ioo ml (10 ,ug/Ioo ml of haemoglobin-iron).1.31.These limits of haemoglobin contamination are difficult to achieve without removing haemoglobin from the serum pool by methods such as ultrafiltration.However, they can be attained if care is exercised in the bleeding of donors and the separation of the serum from the blood clot, The following method is recommended:Bleeding should be accomplished with a thin-walled 16-gauge hypodermic needle with free flow of the blood into iron-free polyethylene plastic bottles.Keep the blood at room temperature for about 16 hr.Ring the clot carefully and spin the specimen at 2500 rpm for 45 min.Decant the serum carefully to avoid contamination with red blood cells.Recentrifuge the serum and decant the serum from red blood cells a second time.Haemoglobin concentration should be measured by a method as sensitive as the benzidine-peroxide technique.