The nuclear-cytoplasmic ratio (also variously known as the nucleus:cytoplasm ratio, nucleus-cytoplasm ratio,<unk> , or N/C) is a measurement used in cell biology. It is a ratio of the size (i.e., volume) of the nucleus of a cell to the size of the cytoplasm of that cell. The<unk>  indicates the maturity of a cell, because as a cell matures the size of its nucleus generally decreases. For example, "blast" forms of erythrocytes, leukocytes, and megakaryocytes start with an<unk>  of 4:1, which decreases as they mature to 2:1 or even 1:1 (with exceptions for mature thrombocytes and erythrocytes, which are anuclear cells, and mature lymphocytes, which only decrease to a 3:1 ratio and often retain the original 4:1 ratio). An increased<unk>  is commonly associated with precancerous dysplasia as well as with malignant cells.
NC ratio
E/A ratio
Oxygen enhancement ratio
Ka/Ks ratio
Extraction ratio
Oxygenation index
Arterial input function
CO2 content