Feasibility of Using Cumulative Red Blood Cell Parameters as a Quality Control Tool During a Pandemic: Insights from the COVID-19 Pandemic

The COVID-19 pandemic affected every section in healthcare including laboratories. Commercial quality control materials were very costly or not available during pandemic even to the Ministry of Health Sri Lanka. Daily cumulative means of laboratory results were recommended as an alternative and effective quality control measure. Yet laboratories did not use this method due to the fear of influence of Covid related changes in test results. This study aimed to determine the plausibility of using cumulative means of red blood cell parameters as reliable internal quality control tools during a pandemic. This retrospective observational study was conducted in a large private sector hospital laboratory in Galle during the pandemic. Monthly cumulative means were calculated for key red cell parameters; RBC, Hb, MCV, MCH, and PCV in the years 2018, 2020, and 2021 using complete blood count reports in patient databases. Cumulative means in 2018 were considered the standard baseline. Monthly cumulative means for 2020 and 2021 were plotted and compared with those of 2018. Total of 14,291, 21,259, and 27,210 CBC reports were collected in years 2018, 2020, and 2021, respectively. Means for RBC, Hb, MCV, MCH, and PCV in 2018 were within reference intervals. Monthly cumulative means for all red cell parameters during 2020 and 2021 fell within calculated range for 2018. Both RBC and Hb means for 2020 and 2021 were consistently above the mean of 2018, while MCV and PCV values were consistently below 2018 mean. During a pandemic like Covid-19, cumulative means of red cell parameters can serve as an effective quality monitoring tool in hematology laboratories.