Shares of Qiagen (QGEN) - Get Report were rising Thursday following a report that said Thermo Fisher Scientific (TMO) - Get Report was considering a purchase of the Dutch molecular-testing company.

Qiagen rose 3.72% to $36.77 in trading Thursday. Shares of the company traded in Germany jumped more than 13%. Shares of Thermo Fisher, the maker of diagnostic equipment, declined slightly.

Bloomberg reported that Thermo Fisher has approached Qiagen about a potential deal. The report cited people with knowledge of the matter.

If completed, the acquisition would be one of Thermo Fisher's biggest-ever deals. According to Bloomberg, the purchase would exceed Thermo Fisher's $5 billion takeover of drug-ingredient maker Patheon in 2017. The company's largest acquisition was its $15 billion purchase of Life Technologies in 2014.

A spokesman for Qiagen declined to comment on the Bloomberg story.

Thermo Fisher CEO Marc Casper told analysts last month that he feels "great" about the company's mergers and acquisitions pipeline, which "continues to be very active," Bloomberg noted.

Thermo Fisher late last month posted third-quarter earnings and revenue that topped analysts' estimates.

The Waltham, Mass.-based company reported earnings of $2.94 a share, topping the estimate of $2.88. The earnings also were 12% higher than the same quarter last year, when the company reported earnings of $2.62 a share.

Thermo Fisher's third-quarter revenue was $6.27 billion, which also topped forecasts and year-earlier revenue of $5.92 billion.