When a lab is interested in your request, you can communicate with the lab directly via your testxchange dashboard.
Just open the detail view of the respective request.
Your correspondent does not have to be online to read your messages. He / She will be informed by email about your message. He / She can read your message at any time on his / her dashboard and answer your message.
You can open the detail view of your request at any time via the 'Open chat' button and see the entire chat history.