The effect of blood storage on differential chromosome staining of human lymphocytes

Human blood was stored for up to 3 days before 66-h culture with 3 concentrations of bromodeoxyuridine (BrdU) (10, 20 and 40 microM). In cultures containing 10 or 20 microM BrdU, the number of cells staining as first division metaphases (MI) increased with storage time. In addition, as the storage time was increased the staining quality deteriorated although this was less pronounced in cultures containing 40 microM BrdU. The implications of these results for routine fluorescence plus Giemsa staining as part of a cytogenetic radiation dosimetry service are discussed, with the recommendation that for accurate identification of M1 cells, the concentration of BrdU should be increased in cultures set up from blood that has been stored for more than 2 days.