Genzyme (Nasdaq: GENZ) announced today that it has agreed to sell its diagnostic business to Sekisui Chemical, a Japanese conglomerate, for $265 million in cash. The sale of the diagnostic unit, which provides raw materials for labs and tests for HDL and LDL cholesterol levels, is part of Genzyme's restructuring plan announced back in May. The unit's 2009 revenue was $167 million.