Modules & VBA :: Audit Trail Returning Primary Index Of A Record Changed

After a lot of reading and consolidating VBA codes for audit trail.How My Audit Trail Works..A module was made for a function named as "Changes" .Then inserted into before update event of a form where I will do the editing of the records.Then I made a table named as Audit.Inside this table I made all the fields I needed such as:

*AuditRecordId[autonumbered]
*FormName[The name of the form for editing]
*Index[The record ID of the record being edited]
*ControlName[The Field being edited]
*DateChanged[Date change was done]
*TimeChanged[Time change was done]
*PriorInfo[for the old value of data being changed]
*NewInfo[For the new value of data changed]
*CurrentUser[The user base on log in form that was set to Global into another module]
*Reason[The reason for changing for future references]

And Here is the Function Code:

Code:

Option Compare Database
Option Explicit
Function Changes()
Dim db As Database
Dim rs As Recordset
Dim strSQL As String
Dim strCtl As String
Dim strReason As String

[code]....

This audit trail function is valid only for one(1) form, due to the limitation of

Code:
Screen.ActiveForm.Controls("SUP ID").Value

where "SUP ID" is the primary key of the record being updated/Change, so if there are Five(5) tables that needs audit trail, there will be also Five(5) forms, as well as Five(5) Function Changes namely; Changes(), Changes1(),Changes2(),etc... because all the table do have their own sets of primary Key.

Is there a shortcut, in such a way that the "rs!Index" will automatically return a value, equivalent to the Primary Key/Record Id of the record being updated/change, given that there are different updating forms for each table to be updated?