Flow General Inc., the struggling McLean-based biomedical and technical instruments company, announced yesterday that it is seeking a buyer for its Worthington division--acquired just 13 months ago for $57.7 million--and may sell off the technology for producing Interferon, a highly publicized product believed to have potential in cancer treatment.

The company, which has lost money in four consecutive quarters and recently replaced its top officers in a management shakeup, said it had retained Citibank to handle the proposed Worthingon sale.

In addition, Flow Chairman Grant C. Ehrlich, who assumed control of the company when President Joseph E. Hall resigned last month, said he was considering "the possibility of either selling or licensing existing technology in certain biomedical areas." Company officials confirmed that this is a reference to Interferon, which they said Flow knows how to make but not know how to market.

"We got it going; the question is what do we do with it," a Flow official said. "Maybe it should be produced and marketed by a pharmaceutical house."

Yesterday's announcement made clear that Flow, which had 1982 sales of $138.1 million, is retrenching and cutting back in an effort, led by Ehrlich, to put the company back on a profitable course.

Ehrlich said in a statement that "the goal of our current efforts is to move our transition period along as quickly as possible but to do so in a strategic manner so that Flow General will emerge as a better defined and a more highly focused company."

Two weeks ago, Flow sold its Flow Sensor division at less than book value. At the time, Flow acknowledged that this transaction would be added to its loss for the March quarter, which the company has said will be substantial.

The Worthington division was described in the company's recent annual report to stockholders as the key to expansion of Flow's international sales.

But Ehrlich said yesterday that divestiture of Worthington was "the most strategic option" for reducing Flow's debt. Flow's long-term debt rose from $8.3 million in 1981 to $45.4 million last year, mostly as a result of expansion. The company's announcement did not say what price Flow was seeking for the Worthington unit.

Company spokesman Doug Poretz said the sale of Flow Sensor and the planned divestiture of Worthington did not presage a selloff of other divisions. Instead, Poretz said, the company was planning to sell or license the rights to produce and distribute products that "don't go directly to our marketing strengths." Flow officials said this refers to Interferon.

Flow stock, traded on the New York exchange, closed unchanged yesterday at 12 5/8. The announcement of the plan to sell Worthington was made after the close of trading.