IOE Receipt Numbers and ELIS Case Status Explained: IOE, EAC, WAC, LIN and Your A-Number

Anatomy of a USCIS receipt number

Every application or petition USCIS accepts gets a 13-character receipt number: three letters followed by ten digits, printed in the top-left box of the Form I-797C Notice of Action and shown in your online account. The letters identify the system or office that logged the case. For paper receipts from the service centers, the ten digits encode the fiscal year, the working day the case was logged and a sequence number; IOE digits are a plain identifier and do not follow that pattern.

The same person can hold several receipt numbers at once. An F-1 student who files Form I-765 for OPT and later a Form I-539 or a Form I-129 petition through an employer will have a different receipt for each, each with its own status. Match the form number printed on the notice to the case you want to check.

Always enter the number without spaces or dashes, and double-check the characters that are easy to confuse: the letter O never appears after the prefix, so a round character in the digits is a zero. The receipt number troubleshooting guide covers the errors that follow a mistyped number.

Sources: Form I-797: Types and Functions; USCIS Service and Office Locator

• Receipt number not working? Causes and fixes
• What is a USCIS receipt number

What IOE and ELIS actually mean

ELIS, the USCIS Electronic Immigration System, is the agency’s online case-management platform. Any form filed through a myUSCIS account is created in ELIS and receives an IOE receipt. USCIS also scans a growing share of paper filings into ELIS at intake, which is why a paper I-765 mailed to a lockbox can come back with an IOE number rather than the service-center prefix an older guide told you to expect.

The prefix changes where the case is stored, not who decides it or how fast. IOE cases are routed to whichever service center or field office has capacity for that form, and the processing time to use is still the one USCIS publishes for the form and category. Treat forum claims that "IOE cases are faster" or "IOE cases get stuck" as anecdotes.

There is no public ELIS website for applicants. People searching for "ELIS case status" are looking for one of two things: the public Case Status Online tool, which accepts any receipt including IOE, or the myUSCIS account, which shows the ELIS case history, notices, requests for evidence and, after approval, the USPS tracking number for the card. Both are described in the next section.

Sources: DHS/USCIS/PIA-056: USCIS Electronic Immigration System (USCIS ELIS); How to Create a USCIS Online Account

• IOE prefix = case created or scanned into ELIS.
• ELIS is internal; applicants reach it through myUSCIS and Case Status Online.
• Processing time depends on the form and category, not on the prefix.

Where to check an IOE case status

USCIS Case Status Online is the public tool. Enter the full receipt number and it returns the latest status message, for example "Case Was Received" or "Case Was Approved". It needs no account, works for every prefix, and shows only the current message, not the history.

Your USCIS online account adds the history, the notices as PDFs, secure messages, the ability to respond to a request for evidence, an address change form and, for I-765 cases filed online, the myProgress estimate. If you filed on paper and received an IOE receipt, the separate Account Access Notice includes an online access code. Sign in, choose to add a paper-filed case, and enter the receipt number, the code and your date of birth. The code expires, but USCIS will email a new one on request. Most, though not all, IOE paper cases can be added this way.

A tracker such as TrackMyOPT stores the receipt, checks Case Status Online for you and emails you when the message changes. It reads the same public status as the USCIS tool, so it works for IOE and service-center receipts alike, and it keeps several cases in one list, for example an I-765 and a spouse’s I-539.

Sources: Case Status Online; How Do I Get a New Online Access Code?

• USCIS case status tracking guide: every status message explained
• How TrackMyOPT case tracking works

1. Copy the 13-character receipt from the I-797C notice or your account.
2. Enter it at USCIS Case Status Online for the current message.
3. Add the case to your myUSCIS account for history, notices and USPS tracking.
4. Optionally save it in a tracker to be alerted when the message changes.

Your A-number: what it is for and why it will not check a case

The A-number, formally the Alien Registration Number, is an 8 or 9 digit number that identifies a person in USCIS records, written as A followed by the digits, for example A123456789. Most F-1 students receive one when their first EAD is approved; it is printed on the card as "USCIS#" and appears on later I-797 notices. People who adjust status or receive other benefits keep the same number for life.

Because it identifies you rather than a filing, the A-number cannot be entered in Case Status Online, which only accepts receipt numbers. Searches for "USCIS case status A number" end at the same answer: find the receipt number for the specific case. The A-number is used instead on later forms, on the Form I-9 for employment verification, at immigration court and when you create or verify a myUSCIS account.

Keep the A-number, the receipt numbers and the SEVIS ID separate in your records. The SEVIS ID (N followed by ten digits) identifies your student record and is used with your DSO and the SEVP Portal, never with USCIS Case Status Online. Entering it in the status tool is one of the most common reasons a "receipt number" returns no result.

Sources: Glossary: Alien Registration Number; Form I-797: Types and Functions

• Where to find your I-94 and travel history
• SEVP Portal guide for OPT

"I-797 tracking": what can and cannot be tracked

Form I-797 is the family of notices USCIS mails: the I-797C receipt and biometrics notices, the I-797 approval notice, and the notices for requests for evidence and decisions. They travel by ordinary first-class mail and have no tracking number. The only way to know a notice exists is the status message or the PDF in your online account, which often appears before the paper arrives.

The card is different. An EAD or green card is sent by USPS Priority Mail with tracking, and once the status reads "Card Was Mailed To Me" the tracking number appears in your USCIS online account. Use it with USPS Informed Delivery to see the envelope on delivery day. If the card has not arrived 30 days after that status, file a nondelivery e-Request.

If an I-797 approval notice itself goes missing, you can request a replacement by filing Form I-824 or, for some notices, through a secure message in your account. For OPT applicants the EAD card, not the approval notice, is the document employers need, so a lost notice rarely blocks work.

Sources: Form I-797: Types and Functions; e-Request: case inquiries and nondelivery

• EAD card status: when the card ships and what to do if it is late
• EAD card lost, stolen, incorrect or never delivered

Example: Wei types his A-number into the status tool

Fictional example: Wei filed a STEM OPT I-765 online and gets a receipt with an IOE prefix. A week later a forum thread tells him IOE cases are "stuck in ELIS" and that he should check "ELIS status" with his A-number. He enters the A-number from his current EAD into Case Status Online and gets an error.

He goes back to the I-797C notice, copies the 13-character receipt, and the tool returns "Case Was Received". He opens the case in his myUSCIS account, sees the receipt PDF and a myProgress estimate, and saves the receipt in a tracker so he stops checking the thread.

The lesson is the one every receipt question comes back to: the prefix is a filing label, the A-number is a person, and the only key that opens a case is the receipt number for that case.