These are used in FDA QSIT manual, but doesn't say what they stand for.
These are the Inspection classification codes. Apart from the ones you have mentioned, the other inspectional codes are as follows -
Inspection Classification Codes:
CAN: Canceled
NAI: No Action Indicated. No objectionable conditions or practices were found during the inspection (or the objectionable conditions found do not justify further regulatory action).
NCC: Non Classified
NIM: No Inspection Made.
OAI: Official Action Indicated. Regulatory and administrative actions will be recommended.
PEN: Pending review and classification.
RTC: Refer to Center: Establishment Inspection Report had been forwarded to Center for final review and classification.
VAI: Voluntary Action Indicated. Objectionable conditions or practices were found, but the agency is not prepared to take or recommend any administrative or regulatory action.
WO: Washout: Firm was visited or inspected, however, not performing regulated studies at time of inspection.
Refer for more details at
http://www.fda.gov/ora/compliance_ref/bimo/glp/wh_list_foreign.htm