Of the 27 companies in the index, 14 firms' stocks were down, while 13 companies' share prices increased.
Revenues were $226.4 million, down from $263.7 million for the same quarter last year, but above the Wall Street estimate of $225.6 million.
Of the 27 companies in the index, 12 firms' share prices retreated last month, 14 companies' stocks increased, and one firm's share value was flat.
Other big gainers last month included Accelerate Diagnostics and Natera, and share prices of 23 of the 27 companies in the index increased month over month.
In issuing a proposed limited local coverage determination for Opko Health's 4Kscore, Novitas changed course from a previously issued non-coverage determination.
The broader market drove down the stock prices of many diagnostics companies. Natera, Guardant Health, and CareDx paced the gainers.
The company reported revenues of $222.5 million, down from $254.9 million in Q1 2018, and below the consensus Wall Street estimate of $241.3 million.
Many diagnostic firms saw gains in their stock prices last month as Invitae and NantHealth also saw healthy increases.
The company's revenues in the quarter rose to $221.9 million from $161.0 million in Q4 2017, but it missed the consensus Wall Street estimate of $245.3 million.
Opko will use the proceeds to fund R&D to further develop its diagnostics and pharmacy portfolio, and for working capital including debt repayment.