COVID testing kits - A new source of accidental poisoning in the UK?

ABSTRACT

Objective: Self-testing kits for COVID-19 are available to the public and commonplace in households. Kits consist of nasal/throat swabs, absorbent testing strips (including a desiccant sachet) and bottles of extraction liquid. Once samples are collected swabs are placed in the liquid to create a sample for lateral flow (LFT) or polymerase chain reaction (PCR) testing. The liquid is a mixture of water, transport mediums, buffers, preservatives and animal proteins and although not intended for human contact, is considered to be low toxicity. Our objective was to analyse enquiries to the UK National Poisons Information Service (NPIS) regarding COVID-19 test kits to investigate potential toxicity. Methods: We conducted a retrospective analysis of enquiries from 1 March 2020 until 31 July 2021. Enquiries were identified from the UK Poisons Information Database (UKPID) and filtered to identify those relating specifically to COVID-19 test kits. Results: In the study period 126 enquiries were received about COVID-19 test kits. One enquiry was regarding ingestion of the desiccant (LFT kit) with all others regarding the extraction liquid. The majority of enquiries (86, 68.3%) related to LFT kits with 9 (7.1%) enquiries regarding PCR kits. In 31 enquiries (24.6%) the test type was not specified. NHS telephone services (NHS 111/ Direct/24) accounted for the majority of enquiries (94, 74.6%), with the remaining from hospitals (12, 9.5%), primary care (10, 7.9%), and other sources (10, 7.9%) including ambulance services and nursing homes. Adults accounted for 69 (54.8%) enquiries with 55 (43.7%) regarding children. Age was not specified in 2 (1.6%) enquiries. Most adult exposures were accidental (67, 97.1%) with only 2 (2.9%) intentional exposures. Accidental exposures were due to the liquid being mistaken for eye drops (24, 35.8%), swabs dipped in liquid before taking samples (21, 31.3%), ingestion of liquid (19, 28.4%), spill of liquid onto skin (2, 3%) and liquid mistaken for ear drops (1, 1.5%). Patients were either asymptomatic (48, 69.6%) or reported mild symptoms only (20, 29%). In 1 enquiry the symptoms were unknown. Paediatric exposures were also accidental with only one intentional ingestion. Enquiries included ingestion of liquid or desiccant (45, 83.3%), liquid mistaken for eye drops (6, 11.1%), and swab dipped in liquid before taking sample (3, 5.5%). Patients were asymptomatic (48, 87.3%) or reported mild symptoms only (7, 12.7%). Conclusion: Almost all exposures to COVID-19 test kits were accidental with the extraction liquid most commonly being mistaken for eye drops. Reassuringly, serious toxicity has not been reported.