cual-id: globally unique, correctable, and human-friendly sample identifiers for comparative -omics studies

The number of samples in high-throughput comparative “omics” studies is increasing rapidly due to the declining experimental costs. To keep sample data and metadata manageable, and ensure the integrity of scientific results as the scale of these projects continue to increase, it is essential that we transition to better designed sample identifiers. Ideally, sample identifiers will be: globally unique across projects, project teams and institutions; be short to facilitate manual transcription; be correctable with respect to common types of transcription errors; be opaque, meaning they do not contain information about the samples; and be compatible with existing standards. We present cual-id, a lightweight command line tool that creates, or mints, sample identifiers that meet these criteria without reliance on centralized infrastructure. cual-id allows users to assign Universally Unique Identifiers, or UUIDs, that are globally unique to their samples. UUIDs are too long to be conveniently written on sampling materials such as swabs or microcentrifuge tubes however, so cual-id additionally generates human-friendly 4-12 character identifiers (CualIDs) that map to their UUIDs and are unique within a project. CualIDs are used by humans when they are manually writing or entering identifiers, while the longer UUIDs are used by computers to unambiguously reference a sample. The adoption of identifiers that are globally unique, correctable, and easily hand-written or manually entered into a computer will be a major step forward for sample tracking in comparative -omics studies within and across projects and project teams.