What does Case number mean?

[missDKmrUSA 7]

I googled a bit to find an answer to understand what the case number means.. I found a post saying this:

What does my USCIS case number mean?

Your receipt contains a case number that USCIS assigns to your case. It is in the following format (ignore the dashes): aaa-xx-yyy-z-mmmm, where

* aaa: The service center that received your case. For example:

SRC - Texas Service Center (formerly Southern Regional Center),

LIN - Nebraska Service Center (named after Lincoln, NE),

WAC - California Service Center (formerly Western Adjudication Center) and

EAC - Vermont Service Center (formerly Eastern Adjudication Center).

* xx: The fiscal year of USCIS, from October 1 to September 30. Cases filed from 10/01/2006 to 09/30/2007 will have xx = 07

* yyy: The working day of the fiscal year when your case is received. 10/01 = 001

* z: Either 5 (in database) or 0 (paper files)

* mmmm: A serial number assigned to your case based on the number of cases received, starting from 0001

Yet, when i try to figure out a case number (for example, starting like this WAC139xxxxxxx) i dont quite understand it...

WAC = california service center

13 = fiscal year 2013

9xx = working day starting with 900 something?? Is that even possible..

Anyone who could explain it?

[Bayareaguy 156]

I'm guessing the format has changed since that was published. All the cases I see have 90x for the supposed working day, and the Z number is 6 for all I have seen from last year up to December, though the fiscal year number seems to be correct. We would need an updated key to be sure.

[bigdog 376]

One of the statictical wizards should be solve this.

[dragonfly928 3]

USCIS Receipt number and case number are two different numbers. Case number comes after your approval and case passed on to NVC.

The info you posted is number after you pay USCIS...but NVC assigns you a case number when they receive your case upon approval by USCIS. This is the number you use there after.