Quidel said that its board rejected offers by Danaher, the parent firm of Beckman Coulter, to acquire the BNP assay business after finding Danaher's proposal "inadequate."
The firm beat the consensus Wall Street estimates on the top and bottom lines as the diagnostics segment saw revenues grow 20 percent year over year.
The company has shut down the Veris molecular diagnostics product line, which Beckman Coulter spent years developing, as a result of its acquisition of Cepheid.
The assay is the firm homogeneous PCT assay for use on Beckman Coulter AU model chemistry analyzers and can be used to manage bacterial infections and sepsis.
The firm's European subsidiary is offering the new senior notes to repay, in part, all outstanding aggregate principal amounts on senior notes due later this month.
The investment bank took note of Danaher's soft organic growth rate in the first quarter, and said it will need to build up its life science portfolio.
Announced during the company's recent analyst day, the instrument could mark a major step in mass spectrometry's ongoing move into clinical applications.
The company beat Wall Street analysts' expectations for sales and earnings per share during the quarter.