What happened?

Shares of medical diagnostics specialist Quidel Corporation (QDEL) are dropping sharply on Friday following the company's announcement of its financial results for the fourth quarter of its fiscal year 2020, which ended on Dec. 31. Investors weren't impressed with Quidel's quarterly update. As of 2:12 p.m. EST, the company's shares were down by 11%. 

So what

Last year, Quidel devised and marketed several COVID-19 tests, and its business got a boost as a result. During Q4, the company's revenue soared by 432% year over year to $809.2 million. Quidel's top line barely came in ahead of the average analyst estimate, which was $809.1 million. The company's revenue from COVID-19 products was $678.7 million. 

Meanwhile, on the bottom line, Quidel reported an adjusted net income of $482.8 million -- or $11.07 on a per-share basis -- compared to adjusted net income and earnings per share (EPS) of $43.5 million and $1 during Q4 of the previous fiscal year.

Man standing on downward-bound graph.

Image source: Getty Images.

Quidel's adjusted EPS beat the consensus analyst estimate of $10.14. For the full fiscal year 2020, the company's revenue increased by 211% year over year to $1.7 billion, and its adjusted EPS was $19.92 compared to $2.97 reported during the fiscal year 2019.

Now what

Quidel's revenue and adjusted earnings were both slightly better than what Wall Street expected, so why is the company's stock diving? Here's my best guess: With an increasing amount of the population getting vaccinated against COVID-19, the need for test kits for the disease might decline.

And while the healthcare company will continue to profit from its coronavirus-related efforts, its revenue growth rate will likely drop. Given that Quidel's stock soared by 134% in the past 12 months -- largely thanks to revenue from its COVID-19 products -- the prospect of decelerating top-line growth isn't appealing to investors, which may explain today's sell-off.