Shares of Abbott Laboratories /zigman2/quotes/203724446/composite ABT +0.21% were down 3.2% in premarket trading on Tuesday after the company beat earnings expectations during a quarter in which sales of its COVID-19 tests made up 20% of total revenue. Abbott had earnings of $1.8 billion, or $1.00 per share, in the first quarter of 2021, compared with $544 million, or 30 cents, in the same quarter a year ago. Adjusted earnings per share were $1.32, against a FactSet consensus of $1.27. The company had sales of $10.4 billion for the quarter, up from $7.7 billion in the first quarter of 2020, against a FactSet consensus of $10.7 billion. This was driven in large part by $2.2 billion in sales of its COVID-19 tests, including $1.8 billion that came in from the company's rapid-testing platforms. Abbott said it anticipates adjusted EPS of $5.00 for 2021; the FactSet consensus is $5.06. Abbott's stock has gained 27.1% over the last year, while the broader S&P 500 /zigman2/quotes/210599714/realtime SPX -0.85% is up 44.8%.