What protocol you are looking at to find missing response?
If it is to find missing HTTP response packets for HTTP requests
One way or analyzing is by going to MENU Statistics > HTTP > Load Distribution and click create stat
The output gives HTTP Requests to server and HTTP Responses from server where one will get a chance to compare and identify for what request the response is missing.
The other way is to display tcp.analysis.flags(duplicate acknowledgements,retransmissions,fast retransmissions etc...)which are generated when an error condition occurs.These packets are really helpful in identifying the error zone.You can play with export information in status bar(the bottom pane) to quickly check these error conditions.
Hope this helps
If you mean: There is no HTTP response to a HTTP request, then there is (unfortunately) no easy way to do that in Wireshark, as there is no HTTP protocol flow analysis, similar to TCP SEQ/ACK analysis.
Can you please add why you need that information (what kind of problem are you analyzing)? Maybe there is a another way to solve your problem.
One idea: You could write a Lua Listener for HTTP. Within that Listener it would be possible to record all HTTP requests and check if there is a (valid) response for each request. But that coding needs to be done (not very hard, but not very easy either), unless you find some ready to use Lua script for this.
please check the latest development version.
According to the answer of @JeffMorris to this question, there is a functionality (implemented in bug8287) that will calculate the delta time between a HTTP request and the response. That feature might help to identify "missing responses" by filtering/sorting on those delta times.