Each sample is in lyophilised form and equivalent to about 5.75 mL of bovine blood. EDTA was used as anticoagulant and two preservatives (gentamycin and 4-hydroxybenzoic acid methylester) were added. Lead nitrate was used to spike the bovine blood. No cadmium was added. The lyophilised blood is kept under nitrogen gas in rubber stoppered vials. The mass of lyophilised material contained in a vial is about 1.1 g. The residual water content of the sample is below 0.01 g/g (mass fraction). European Reference Material ERM®-CE196 was originally certified as BCR-196. It was produced and certified under the responsibility of the IRMM according to the principles laid down in the technical guidelines of the European Reference Materials ® co-operation agreement between BAM-IRMM-LGC. Information on these guidelines is available on the Internet (http://www.erm-crm.org).