Simple method for granulocyte-macrophage cell culture and staining in soft agar: comparison with a standard research technique.

A modified, small volume, two phase, disc culture system for CFU-GM (seven and 14 days of incubation) was compared with a standard single layer system. The 1 ml single layer cultures were counted unstained in situ before both sets of cultures were transferred to glass slides for staining. Bone marrows were cultured from forty eight subjects, including normal controls and patients with acute non-lymphoblastic leukaemia, acute lymphoblastic leukaemia, and myelodysplastic syndrome. Observer error was least with the disc cultures, whereas variation between replicate cultures was similar for both methods. A high degree of correlation was found between the two methods for both day 7 (r = 0.90) and day 14 (r = 0.91) cultures. The number of colonies and clusters was higher with the disc system, indicating better cloning efficiency. Analysis of subsets of clinical groups showed similar patterns of abnormality with both systems. The simplicity of the method makes the use of this technology possible in most laboratories, and the superior morphological resolution may increase the clinical usefulness of such studies.