accuracy antigen check checking colloidal coronavirus covid-virus detection diagnosis diagnostic-aid dropper drops home-use immunochromatographic-technology kit limitations limited lysis-buffer measuring-instrument medical nasal-secretion negative-result plastic quality-control-C-line rapid rectangular result sample sampling-tube self-testing test test-cassette testing extraction-reagent-tube nasal sterile-swab swab almost-derelict architecture balconies building closed compound compound-walls decay Dirt discoloration estate façade front front-doors grass grime home house in-use isolated isolation light locked neglect overgrown padlock padlocked-doors poverty property Rooms secured semi-rural-area shut trees uninviting wall walls weeds windows abundance availability available coconut coconut-flakes coconut-juice coconut-kernel coconut-meat coconut-milk coconut-water coconuts cooking copra drink dry-drupe edible fibrous fibrous-husk food for-sale fresh fruit fuel grated-coconut green hard-shell harvested heap inner-flesh load mature natural-foods oil one-seeded-drupe palm-tree produce raw saturated-fat shell shredded-coconut trolley tropical-diet water-coconuts yellowing young 3D character illustration key keys real boy child frog job kid photo black coffee coffeepot groningen household illustrator people shape silhouette vector white britain british England english manor mansion park place stone wakehurst cleaning cleaning lady clothes domestic housekeeper housemaid housewife laundry peg pegs stretch wash converted fence former Mawddach Picket platform railway residence station unusual wales welsh