Shares of Abbott Laboratories /zigman2/quotes/203724446/composite ABT -1.48% were down 0.8% in premarket trading on Wednesday as surging revenue for its COVID-19 tests carried the company past earnings and sales estimates. Abbott had earnings of $2.1 billion, or $1.20 per share, in the fourth quarter of 2020, up from $1.0 billion, or 59 cents per share, in the same quarter a year ago. It had adjusted earnings per share of $1.45, against a FactSet consensus of $1.35. Abbott's sales for the quarter were $10.7 billion, up from $8.3 billion in the fourth quarter of 2019. The FactSet consensus for sales was $9.9 billion. This is largely due to a 333% jump in sales of rapid diagnostics, to $2.4 billion, fueled by demand for the company's rapid- and PCR-based COVID-19 tests. Abbott said it expects earnings per share of at least $3.74 and adjusted EPS of at least $5.00 in 2021. Abbott's stock has gained 28.0% over the past 12 months, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.48% is up 16.8%.