I don't know if this will work for you l copied it from a another site that was around.
Its not so important & is simple - but can come handy if needed.Okay so did You ever came in a situation that you needed to know that if "ABC" has you number stored in his cell or not.
1) There is an option in WhatsApp known as "Broadcast list"
2) Tap on new broadcast list.There will be a note below "IMPORTANT: Only contact with "YOUR NUMBER" in theiraddress book will recieve your broadcast messages.
"3) Add the contacts that you want to check . you can add all your contact and check all at once
.4) Once the broadcast list is made,
5) Just forward a Joke in that broadcast list .Results: who so ever doesn't have your number feeded will not receive the msg, and You will not get a double tick or blue ticks .
Hope it works