Pharmaceutical drugs, hazardous chemical compounds and other products must be evaluated for their hematological toxic potential for their safety use. In vitro CFU-GM clonogenic assay is one of the best test systems to evaluate the adverse toxic effects of xenobiotics on the blood forming system. The test involves exposing the mice bone marrow cells to various test substances at different concentrations and estimating the inhibition of the proliferation of the CFU-GM colonies. This technique is best use for determining the human maximum tolerated dose (MTD). It describes the use of in vitro CFU-GM assay for characterizing and predicting hazards to humans.
CFU -GM assay is used to predict myelosuppression of cells caused by chemical induction as well as to find the haematotoxic potential of chemical compounds and the harmful effects of xenobiotics on the proliferative ability of the progenitors. CFU–GM was assessed on different concentrations (4×10-8 mg/ml to 4×10-1 mg/ml) of potassium nitrate in the bone marrow taken from Charles Foster (CF) rats under inverted microscope at 25X magnification. No such effect of the potassium nitrate was seen which could be related to the molecular mechanism of toxic effect of potassium nitrate used in the study.