A system for providing ultraviolet treatment to light absorbing liquids, such as biological liquids in a medical instrument, is disclosed. The system can include an ultraviolet impenetrable housing configured to enclose a portion of the medical instrument containing the biological fluid. At least one ultraviolet radiation source is integrated within the housing that emits ultraviolet radiation towards the medical instrument and the biological fluid. A control unit is configured to direct the ultraviolet radiation source to treat the biological fluid with ultraviolet radiation.