What happened

Shares of Guardant Health (GH 1.11%) were up 14.8% for the week as of Thursday afternoon and rose as much as 19.8% for the week, according to data provided by S&P Global Market Intelligence. The healthcare stock, which focuses on oncology diagnostic tests, closed at $23.65 a share last week. Its shares rose to as high as $28.33 on Thursday. The stock is down less than 1% for the year.

So what

It was a big week for Guardant. On Monday, the biotech company named a new chief operating officer, Ines Dahne-Steuber, and also promoted senior vice president of technology Darya Chudova to chief technology officer. On Tuesday, the company reported updated results from its blood-based technology to detect early stage colorectal cancer (CRC). The ECLIPSE (Evaluation of ctDNA LUNAR Assay In an Average Patient Screening Episode) study looked at more than 20,000 patients in determining the success of the company's Shield blood test for detecting CRC in adults at average risk of getting the diseases. The test was 83% sensitive in detecting patients with CRC and 81% sensitive in detecting CRC in stages 1 to 3. 

The best news, though, and the one that most moved the needle for investors was the company's first-quarter earnings report that showed an increase in revenue year over year. The company attributed increased clinical volume for first-quarter revenue of $128.7 million, up 34% over the first quarter of 2022. The company reported 39,100 tests to clinical customers, up 45% year over year, helped by the Food and Drug Administration's approval in January of the company's Guardant360 CDx test to find ESR1 mutations in metastatic breast cancer.

Now what

The only bad news in the first-quarter report was that the company lost $133.5 million in net income, compared to $123.2 million in the same period last year. However, that's because the company has been able to ramp up sales efforts and the increase was not that much. Guardant also recently got Medicare approval for Guardant Response, a blood-only biopsy to check for solid tumors, so that should help increase revenue going forward.