The example embodiments are directed to a system and method for detecting phantom data items in a blockchain transaction. In an example, the method includes one or more of generating a transaction data set during a read phase of a blockchain transaction, the transaction data set including an identification of each query of the transaction executed during the read phase and results of each query, generating a validation data set by re-executing each query during a validation phase of the blockchain transaction, the validation data set including query results of each respective re-executed query, determining whether the blockchain transaction observes one or more phantom data items based on the query results of the transaction data set and the validation data set, and, in response to determining the transaction observes the one or more phantom data items, preventing the transaction data set from being written to the blockchain.