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

我接到USCIS關於I-485 電話查詢的來信，“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具體查什麽？曾看過Radiology談過，如果是GC的check,就包括Identity Check/Security Check/ Background check （包括海外調查）。那麽是否意味我的Identity Check/Security Check已完成？