Using the instant exchange may not be a perfect way to hide your privacy but if we look at the OP point of view, he is only concerned with that ordinary people can't trace him.
Still depends. Many exchanges have their central wallets publicly identified. If someone knows that OP is using one of these exchanges to swap his bitcoin to litecoin, for example, then they can simply look for any litecoin transactions of the same value at the same time.
Blockchain analysis companies won't investigate unless they are hired by someone to trace anyone and in this case, OP have no concerns about it.
There are almost certainly blockchain analysis companies which passively scan all transactions and make any easy links or easy identifications they can. Far easier for them when they need to investigate some specific transactions to already have all the groundwork done already.