Unlike human- and animal-based serum and urine, SeraSub and UriSub are stable at room temperature, are free of microbiologic contaminants and have unmatched lot-to-lot consistency. Remarkably, SeraSub and UriSub also have the ability to preserve many types of analytes including sensitive enzymes, proteins, haptens and drugs-of-abuse analytes. SeraSub and UriSub can thereby eliminate the need for storage by lyophilization (freeze-drying), reducing costs and any chance of error during reconstitution.