Is it a dbSNP reference SNP ID?
See also
Other scibio detectors:
is_asin(),
is_bibcode(),
is_ensembl_id(),
is_icd10_code(),
is_icd9_code(),
is_uniprot_id()
Examples
is_snp_id(c("rs3918290", "rs429358", "3918290", NA))
#> [1] TRUE TRUE FALSE NA