a stain of contrasting color that is used when the principal stain does not show the structure clearly
例句
Double staining involves the use of two stains;the second is called the counterstain. 复合染色过程利用了两种染料，后一种被称为复染剂。
It is often used with a green counterstain such a fast green or a blue counterstain, e.g. hematoxylin.See staining. 使用时常可与其绿色对应染料（固绿）或蓝色对应染料（苏木精）套染。
Labelling microcircumstance, the size of vessel opening diameter an d counterstain may also affect the result. 标记微环境，血管开口大小和复染可能影响标记结果。
They do not fade or damage specimens.Examples include fast green and the counterstain safranin.See also negative staining. 它们不会褪色或腐蚀标本，例如用番红固绿复合染料对标本进行永久复染。
RESULTS: Primarily cultured cells were colored with CD44 in-situ hybridization, kytoplasm as huffy and nucleus as blue by counterstain. 结果：原代细胞以CD44原位杂交显色，胞浆呈棕黄色，胞核经苏木精复染呈蓝色。
