EB2 I-485 delayed. 请教Radiology等高手，Background check

我接到USCIS关于I-485 电话查询的来信，“The processing of your case has been delayed. A check of our records establishes that your case is not yet ready for decision, as the required investigation into your background remains open”。background具体查什么？曾看过Radiology谈过，如果是GC的check,就包括Identity Check/Security Check/ Background check （包括海外调查）。那么是否意味我的Identity Check/Security Check已完成？