SPWorkItem.ItemGuid property

Provides a globally unique identifier (GUID) of a list item when a work item must be correlated with a specific list item. This is an optional property that is used when working with list items.

Namespace:  Microsoft.SharePoint
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)

public Guid ItemGuid { get; }

Property value

Type: System.Guid
Returns a GUID for a list item associated with an SPWorkItem object.

Compare ItemId.