The use of whole blood capillary samples to measure 15 analytes for a home-collect biochemistry service during the SARS-CoV-2 pandemic: A proposed model from North West London Pathology

Abstract

Background The COVID-19 pandemic has drastically changed the delivery of secondary care services. Self-collection of capillary blood at home can facilitate the monitoring of patients with chronic disease to support virtual clinics while mitigating the risk of SARS-CoV-2 infection and transmission. Objective To investigate the comparability of whole blood capillary and plasma venous samples for 15 routinely used biochemical analytes and to develop and pilot a user-friendly home-collection kit to support virtual outpatient clinical services. Methods To investigate the comparability of whole blood capillary and plasma venous samples for 15 routinely requested biochemical analytes, simultaneous samples of venous and capillary blood were collected in EDTA and lithium-heparin plasma separation tubes that were of 4–6 mL and 400–600 µL draw volume, respectively. Venous samples were analysed within 4 h of collection while capillary samples were kept at ambient temperature for three days until centrifugation and analysis. Analyte results that were comparable between the matrices were then piloted in a feasibility study in three outpatient clinical services. Results HbA1c, lipid profile and liver function tests were considered comparable and piloted in the patient feasibility study. The home-collect kit demonstrated good patient usability. Conclusion Home collection of capillary blood could be a clinically-useful tool to deliver virtual care to patients with chronic disease.