# Inbox Item Follow-Up

When you promote an _Inbox Item_ to a follow-up _Case_, you can compare all the data from the _Inbox Item_ with the data on the previous _Case_ version. The <a href="/en/lr/826980/">_Inbox Item to Case Compare_ page</a> appears when you select _Compare Details_ on the <a href="/en/lr/01141/#page">_Potential Matches_ page</a>.

While reviewing the data, you decide how information from an _Inbox Item_ is merged with the previous _Case_ version to create the follow-up _Case_. You can compare data from standard and custom fields at the _Case_ level as well as from child records (such as _Case Adverse Events_). After _Case_ promotion or merge, Vault attaches a <a href="/en/lr/907890/#fu-promotion">change log</a> to the _Inbound Transmission_.

## Prerequisite

To use the Inbox Item Follow-up feature, your Admin must <a href="/en/lr/01347/">enable Inbox Item Follow-Up Case Compare</a>.

## Optional Configuration

To align with your organization's business process, your Admin may configure:

* <a href="/en/lr/740208/#follow-up-options">_Case_ promotion for _Inbox Items_ with mismatching _WWUIDs_</a>:  By default, to promote an _Inbox Item_ to a follow-up _Case_, the _WWUID_ on the _Inbox Item_ must match the _WWUID_ on the _Case_. However, your Admin can configure your Vault to allow mismatched _WWUIDs_. If the _WWUID_ value on the _Inbox Item_ is not found in a _Case Identifier_ on the matching initial _Case_, Vault maps the _Inbox Item WWUID_ to a _Case Identifier_ upon promotion to a follow-up _Case_.
* <a href="/en/lr/691317/#creating-follow-up-or-merging-to-current-study-cases">Isolate blinded clinical trial information</a>: If your Admin has configured your Vault to isolate blinded Product information on clinical trial study _Cases_, see additional considerations when completing these actions.

## PMDA Considerations

For information on how Vault maps Japan-specific objects and fields when creating a _Follow-up Case_ from an imported file, see <a href="/en/lr/735519/#merge-to-in-flight-and-promote-to-follow-up-cases">PMDA E2B(R3) _Case_ Import</a>.