Accession PrefixAccession NameDefinitionExample
SRASRA submission accessionThe submission accession represents a virtual container that holds the objects represented by the other five accessions and is used to track the submission in the archive.Since the SRA accession number is an artificial packaging construct, there is no example available since the SRA accession number has no specific response page
SRPSRA study accessionA Study is an object that contains the project metadata describing a sequencing study or project. Imported from BioProject.HTML
SRXSRA experiment accessionAn Experiment is an object that contains the metadata describing the library, platform selection, and processing parameters involved in a particular sequencing experiment.HTML
SRRSRA run accessionA Run is an object that contains actual sequencing data for a particular sequencing experiment. Experiments may contain many Runs depending on the number of sequencing instrument runs that were needed.HTML
SRSSRA sample accessionA Sample is an object that contains the metadata describing the physical sample upon which a sequencing experiment was performed. Imported from BioSample.HTML
SRZSRA analysis accessionAn analysis is an object that contains a sequence data analysis BAM file and the metadata describing the sequence analysis.

From: Understanding SRA Search Results

Cover of SRA Knowledge Base
SRA Knowledge Base [Internet].

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.