What happened

Shares of Guardant Health (NASDAQ:GH) jumped 12.7% on Friday for no apparent reason. Shares of the test maker have been on a roller coaster this week: down on Tuesday after the company reported fourth-quarter results, and back up on Wednesday.

With the broader market down this week, Friday's move could be that investors are fleeing to companies that are less likely to be hurt by the COVID-19 coronavirus outbreak.

So what

Guardant Health sells its Guardant360 test for patients with advanced cancer to profile their tumors through a simple blood test and identify genetic alterations in the tumor that doctors can exploit with medications specific for that type of tumor. Cancer patients are still going to be tested even if the COVID-19 outbreak becomes more widespread.

The healthcare company also has a test called GuardantOMNI, which analyzes significantly more potential mutations and is used by pharmaceutical companies in their clinical trials. Again, those studies aren't likely to be shut down if COVID-19 spreads throughout the U.S. as the patients are still going to need treatment.

Doctor working at a computer

Image source: Getty Images.

Now what

It should be noted that through the roller coaster of a week, Guardant Health ended the week down about 2%, which seems reasonable given the fairly solid fourth-quarter results.

Guidance for this year is for revenue in the range of $275.0 million to $285.0 million, up 31% year over year at the midpoint and higher than the analyst consensus estimate of $273.1 million.

The loss this year may be more than investors were expecting, but as fellow Fool Keith Speights noted, the company is investing in the future through its LUNAR program for the early detection of cancer and recurrence monitoring, which should payoff in years to come.