UPDATE 1-Osmetech to leave AIM, new parent co to list on Nasdaq

* Osmetech to be a unit of GenMark, a new US-based co

* GenMark plans to raise up to $40 mln in US IPO

* Osmetech CFO steps down, names replacement

* FY pretax loss 12.9 mln stg vs 15.3 mln stg a yr ago

* FY revenue up 81 pct to 638,186 stg (Adds details)

March 19 (Reuters) - Diagnostic specialist Osmetech OMH.L posted a narrower full-year loss and said that it would delist from AIM and reorganise as a unit of a newly incorporated U.S.-based company that would be listed on Nasdaq.

Osmetech said it would become a unit of GenMark Diagnostics Inc, which plans to raise up to $40 million through an initial public offering.

Osmetech's shareholders would hold shares of GenMark, and the move would provide more liquidity as the majority of its shareholders were based in the United States, the company said.

Osmetech said Chief Financial Officer David Sandilands would step down on Friday and be replaced by Steven Kemper, senior vice president of finance at its unit, Osmetech Technology Inc.

For the year ended Dec. 31, Osmetech's pretax loss narrowed to 12.9 million pounds ($19.7 million) from 15.3 million pounds a year ago.

Revenue rose 81 percent to 638,186 pounds.

Osmetech said after December-end it secured a $4 million debt facility that is available until July 12, 2011, and said it had sufficient funds for the next 12 months.

Shares of Osmetech closed at 1.9 pence on Thursday on the London Stock Exchange.

($1=.6558 Pound) (Reporting by Shivani Singh in Bangalore; Editing by Anne Pallivathuckal)