nhsnumber Validate NHS number http://www.isb.nhs.uk/documents/isb-0149 as per http://www.isb.nhs.uk/documents/isb-0149/amd-136-2010/index_html See http://www.datadictionary.nhs.uk/data_dictionary/attributes/n/nhs/nhs_number_de.asp?shownav=1